InCider198304

April 1983 ’ Logo Gets Down to Business —usas295 uxe200 I er. Green's Apple* Magazine lle Software... | . What Works? SHtaayiand MeEad Games How to Pra 1 i 04 | | ie) | 74470 mn | * Apple® is a registered trademark of Apple Computer Inc. ADVANCED DEVELOPMENT PACKAGE SPECIALLY TARGETED. Works in harmony with your z-card/epm equipped Apple II. No more floppy shuffle. Fast one pass compiler that doesn’t generate unnecessary intermediate files which require further assembly. PROFESSIONALLY DESIGNED. Crafted by a project team with over 15 years of Pascal programming experience. A powerful Pascal that includes all the features necessary for professional program development including random files and dynamic strings. INCREDIBLE SPEED. Resultant stand alone programs execute 10-20 times faster than the equivalent Basic or up to 4-1/2 times faster than U.C.S.D. programs. TRADEMARK CPM Digital Research Apple Apple Computers ucsD University Calif. San Diego Alcor Paseal Alcor Systems POWERFUL TEXT EDITOR. Has Macro capability, reconfigurable and understands smart terminals, EXCEPTIONAL DOCUMENTATION. Includes 250 page documentation pkg. that guides you step by step. OPTIONAL ADVANCED DEVELOPMENT PKG. Includes Optimizer and Native Code Generator for even faster executing programs, ADP: $125 + shipping. ALCOR PASCAL; A new standard of excellence from the professionals at Aleor Systems. CALL OR WRITE for a free 20 page technical brochure with all the facts, 214-226-4476. Pascal System: $199 + shippin; Alcor Systems 800 W. Garland Ave. LCOR Garland, Texas 75040 Dealer Inquiries Invited Circle 1 on Reader Service card, THE GRAPHIC SOLUTION Solve your toughest communication problems with the Graphic Solution™, a sophisticated, new graphics package from Accent Software. ‘e captivating sales presentations and product demon- hat will both intrigue and nts and customers. i you'll see your elop educational materials and training aids that MIX T! AND GRAPHICS on the screen, breathing new life into abstract, hard-to-grasp cepts. Mix programs too. Images can be displayed on back- grounds loaded from an: other programs. Construct custom TYPEFACES AND TYPESIZES to balance the usta Clements. PERSPECTIV. ES. Add text and animate the data to show the relative rates of change for your most important information. Like cash flow projections. Or revenue estimates. Plot flowcharts, time and motion studies, industrial process flows with COLOR-CODED ELEMENTS high- lighting critical paths. Animate the sequences to show how flows actually progress. Work with live action? Prepare film and videotape storyboards using the unique FRAME-BY-FRAME graphic sequencer that lets you create and animate a video story before shooting. Whatever your sept co communication demands—in the hard look at The Graphic S £ You'll like what e ip! olution requires a ith ROM Applesoft ACCENT SOFTWARE, INC. 3750 Wright Place, Palo Alto, Calif. 94306 Telephone 415-£ Circle 251 on Reader Service card. Apple is a registered trademark of Apple Computer, Inc. sj e AZ Vol. 1 No. 4 in — y { e if Downloaded from www.Apple2Online.com April 1983 ‘The Apple Combination Lock, p. 108 DEPARTMENTS Hot Cider 6 by Wayne Green Fermentations 10 Guest editorial InCide Out 14 Highlights of the issue Letters 16 Applewatch 18 Lisa, and the rest The Applesoft Adviser 24 If/Then and subroutines The Assembly Advantage 44 Getting started with Speed/Asm by Randy Hyde Bent on Business 44 Dollars-per-person-per-hour Interaction—A Child’s World 150 by Tobi Hoffman Reviews 152 Wavy Navy; Labyrinth; Pest Patrol; Aztec Calendar 160 Index to Advertisers 162 Fudge It! 165 Block shapes IIPs Company 176 Portable Basic New Software 184 New Products 190 Cider Vinegar 194 Oops! Cover photo by yam Siegel ARTICLES Solving Problems The Apple With Logo 50Q Combination Lock 106 List processing Protecting disk files by Greg Stone by Harry White Dandy DOSEnchancer 56 Plan YourRetirement ]]0 Diversi-DOS reviewed Helpful advice by Steven A. Schwartz by G.R. Brieger Practically Pascal: Losers[HaveKnown 114 Part1 62 Clearly creative appraisals An application you can use by Chuck Doherty by John Stephenson Star Dust 116 Space Empires 8 — Gamemaker utility 80/Apple conversion by David Schroeder by Lee E. Sumner, Jr. Logger) Tle Software Arcade game fun Compatibility—A Report "72 by Alan Foxx ie ae WritingforReaders 194 A plea for good docs Charting the Future by Fred Huntington i + GRAP! With pfs: GRAPH _84 Con Job 126 eview + , by Stephen C. Ross Controlling screen displays by Paul Raymer DBase II: Expect ToBe Amazed! 9) TE WORKS! 147 n- -. : quick tip by Gregory R. Glau . y Bob Blaske Rots ba hyzvin Feta 148 ir Name ItBeagle Bros? 96 gy Michael L. Waugh Business profile by Bert Kersey ‘Toeveryone who enjoyed Joe Magee’s"EPROM Edification” in last month's issue: Watch for a P follow-up in May that will sh how to List Handler 100 carte eiuhiy read EPROMSs into ‘Apple Review memory. by Bill DeVille inCider (ISSN pending) I published 12 times a year by Aztec review, p. 152 1002001 Inc... 80 Pine St, Peterbornagh, NH 03458, Phone: 603-924-9471. Second class postayte pending al Peterbor- ough, NH, und additional mailing offices, Subscription ralesin U.S. are $25 for one year und $53 for three Canada and Mexico, $27.97—one year only. U. drawn on a U.S. bank, Canadian distributor: Micro Distri Duting, 409 Queen St. West, Toranto, Ontario, Canada MSV 2A5, BC Canadian distributor: Craymar Data Ser- ces, Ltd., #4 258 E. Ist Ave., Vancouver, BC VST 1A6 Ds P.O. Bor 782815. Sandon, South Africa 2146. AILU.S. and ‘Canadian subscription correspondence should be addressed to inCider, Subscription Department, P.O. Box 911, Farm= Ingdale, NY 11737. Please inelude your address label with any correspondence. Postmaster address changes to inCider, Subscription Services, P.O. Box 911, Farmingdale, NY 11737, Entire contents copyright 1983 by 1001001 Ine. 4 Gider April 1983 You and RAVEN, an experimental armored vehicle. are Earth's only defense against the entire Imperial Arcturan Armada. Instantly transported through space by the recently discovered Warp Link, you battle Arcturan tanks and flyers from one of Seven levels to another, until only you remain and reign as the Supreme Terran Hero. THE ULTIMATE 3 ACTION ARCADE GAME! Fast 100% Machine Language. Requires Apple I, 1l+ or lle* “Apple Il is a trademark of Apple Computer, inc Follow the adventures of RAVEN with STELLAR 7, the ALL NEW, 3-D, action arcade game from Software Engineering Corporation STELLAR 7 promises to be everything you'd expect from a High-Res, action packed thriller For Ordering send $34.95 pilus $2.00 shipping and handling to: SEC P.O. BOX 10854 Eugene, Oregon 97440 Or CALL TOLL FREE 1-800-547-8009 in Oregon call 1-503-342-1298 VISA-MASTERCHARGE Welcome Dealer Inquiries Invited. SECond to none! 983 SOFTWARE ENGINEERING CORPORATION. Circle 27 on Reader Service card. Hot Cider Wayne Green Many of us were starting to look for Volkswagen-type ads for the Ap- ple II that go something like, “How Long Can We Keep Handing You This Old Line?” After all, the II ripened in 1977, six years ago, which is about two generations in computer lifetimes. Considering the rapid de- velopments in technology, that is an amazing life for a high tech product. Yet, when I think about it, I have to admit that computers are radically different from other products. Their total dependence upon a combina- tion of software and user skill gives them a far longer life than is possible for a hardware product alone. In- deed, just look at the changes we’ve seen in other high tech products dur- ing this same period. Watches, under pressure from Casio, have changed considerably, as have calculators, radios, stereos, and so on. The Apple II has been changing too, but it has been a low visibility change—one brought about by growth in software and by information on how to use the system. We face a serious drawback when hardware makes a big change. Many or all of the hard-won gains in pro- grams and user information—which thousands of patient (and impatient like me) people have supported— are lost. Radio Shack has been ruthless in this regard. One gets the strong im- pression that Radio Shack begrudges any product that they don’t make money on. I’ve talked with Tandy insiders who have put it just that bluntly. One of the great benefits that man has over most other living things is Remarks From the Publisher. . . The e Is Here, And Lisa Too! time binding—the ability to pass along learned lessons to each new generation. We have this in consis- tent generations of computers, and it is of inestimable value. With Radio Shack, we have to go back almost to square one with each new system, losing untold man hours of programs and information on how to use the system. With the Apple we've had this long buildup of infor- mation and I think that is more at the heart of the success of the Apple than any other single factor. It may have been fortunate in the Jong run that the Apple III bombed. It “It is unfortunate that many computer stores do not yet appreciate the values of the Apple.’’ was modestly compatible with the II, yet for those of us who have been us- ing the [II and the II, the improve- ments achieved seem minor compared to the value we find in the Il, as en- hanced by hundreds of magazine arti- cles on its use and thousands of pro- grams enabling it to do a wide range of chores. Perhaps I wasn’t as enthusiastic as many of the Apple people about the long awaited unveiling of their new models. And I'm not dying to see the promised Macintosh model, unless it is 100 percent compatible with Apple TI software and won't throw away all that we've taken months (and even years) to learn about using the IT. It is unfortunate that many com- puter stores do not yet appreciate the values of the Apple and have been emotionally discounting it because of its age. This has led to price discount- ing, which has been devastatirig. Many Apple dealers have been ac- tively discouraging Apple sales and pushing lines where they make sub- stantially more money per sale. In this case the welter of Apple advertis- ing has been working against the company. Perhaps it is time for Apple to take a serious look at the whole sales pic- ture, They should recognize that sell- ing the Apple concept to dealers is as important as selling it to the end customer. When prospective Apple buyers are smothered with dealer en- thusiasm for some higher ticket com- puter, it is time to make a major push to get things back into kilter. It’s pos- sible that the $10,000 Lisa will help with this. But dealers are a key to computer sales and should be honored as such, This means that they should be given all possible help in selling the prod- uct. They should have the informa- tion they need: video tapes to make up for undertrained salespeople, easi- ly understandable brochures, help. at local shows, reprints of good equip- ment reviews, and a place to call for technical, ale, and delivery infor- mation. In Selling Micros, my dealer oriented magazine, I recently pub- lished a list of 13 important areas where a manufacturer should sup- port dealers. Making the Apple easier to use, via 6 Gider April 1983 STAMP OUT HIGH PRICE On Apple® Software & Accessories... .. without sacrificing on prompt delivery or quality service. Micro Mountain sells everything at prices substantially less than the manufacturer's list. Since we maintain such a large inventory (1000's of items in stock) most orders can be filled and shipped within 24 hours after you order. And, because Micro Mountain is one of the largest retail distributors of Apple® Software in the world, we will be here should you need service at anytime after you receive your order. So, if you're interested in— Low Prices, Prompt Delivery AND Quality Service, SHOP AT... il mountain NCteey FRANKLIN COMPUTERS fétrmce: Locksmith ......... List Handler ....... $6450 Monitor -........ 914759 Bomb Alley ........ $4750 Wild Card ........910950 Micro Modem il ..$27750 Tax Manager sodee $14750 Market Analyzer _$27550 Visicale 3.3... 918750 Alegebra lV ........ $2650 ‘Solo’ Disk Drive .. 927959 46K Ram Card .... 95950 Rhymes & Riddles . $2359 Word Handler... 913950 KENSINGTON MICROWARE SystemSaver 550 MultiPlan ........ $21950 -ASK FOR FREE CATALOG- ert 32.50 SHIPPING AND HANDLING FOR ALL SOFTWARE ORDERS, ADD ADDITIONAL $3.00 FOR BLUE LABEL (Ain. SHIPPING ON HARDWARE ITEMS—EXTRA. Washington PHONE IN Teta ert, See We gel MASTERCARD WSO +4) YOUR ORDER ; € —TOLL FREE— | STREET SINUS" (800) 854-5649 | Washington State residents g CITY. STATE & ZIP. Oo Any order : i) of 3 or more se phone numbers in CARO EXP, DATE programs entitles you to ank.at Right your choice of Original ORDER PHONE HOURS: SIGNATURE ent ® Adventure Game'ol Applesot Mon.Fri.9to6 (PST) 14517 N.E. 169th ST., WOODINVILLE, WA 98072 Tutorial on disk FREE! | Sat. & Sun. 10102(PST) © ORDER PHONE — Outside Wash. — (600) 854-5649 Wash. Residents & Cust. Service (208) 483-2000 Bl ne ee 2 ono os PRICES SUBJECT TO CHANGE WITHOUT NOTICE Circle 55 on Reader Service card. April 1983 @ider 7 ‘Hot Cider- PUBLISHER/EDITOR ‘Wayne Green EXECUTIVE VICE PRESIDENT Sherry Smythe-Green GENERAL MANAGER Debra Wetherbee ASSISTANT TO PRESIDENT Matt Smith ASSISTANT PUBLISHER Jeff DeTray CORPORATE CONTROLLER Roger Murphy ASSISTANT TO CONTROLLER Dominique Smith CIRCULATION MANAGER 603-924-9471 Patricia Ferrante BULK & NEWSSTAND SALES MANAGER Ginnie Boudrieau ADVERTISING, 603-924-7138 David Schisster, Manager; Denis Duffy, Craig Everett: Sales; Patty Lesser: Advertising Coordinator. New England Advertising Representatives: John A. Garland, Frank Surace, Garland Associates Inc., Box 314 SHS, Duxbury, MA 02332 617-934-6464 PRODUCTION Nancy Salmon, Manager; Michael Murphy, Assistant; Frances Benton, Michael Ford, Phil Geraci, Donna Hartwell, Kimberly Nadeau, Lynn Parsons, Deborah Stone, Theresa Verville, Robert Villeneuve, Karen Wozmak; ‘Ad Coordinators: Paula Ramsey, David Wozmak, Mary Seaver; Advertising Production: Bruce Hedin, Fiona Davies, Scott Philbrick, Jane Preston PHOTOGRAPHY ‘Thomas Villeneuve, Supervisor; Katherine Coker, Sandra Dukette, Laurie Jenison, Irene Vail TYPESETTING Sara Bedell, Supervisor; Marie Barker, Melody Bedell, Michele DesRochers, Jennifer Fay, Prem Gongaju, Lynn Haines, Linda Locke, Nancy Wilson-Newman, Debbie Nutting, Lindy Palmisano, Susan Weller DESIGN Jonathan Graves, Creative Director; Christine Destrempes, Design Director; Joyce Pillarella, Supervisor; Denzel Dyer, Howard Happ, Susan Donohoe, Laurie MacMillan, Dion Owens, Diane Ritson, Susan Stevens, Donna Wohlfarth the Lisa approach, is certainly a good idea. Few people have gotten the full benefit of programs such as VisiCale because they are so complicated to learn and use. Computers should be made easier to use. Yet it’s difficult for people—and that includes engi- neers—not to go with trends. The early Apple developments set a trend, with the switch from cassette to flop- py disk. Yet, in perspective, Apple didn’t do users any favors when they cut the cassette umbilical cord. The cost of a cassette recorder is small and of value to the computerist. Most of us have one around for other uses anyway. Sure, cassettes are ineffective for storing data that is needed quickly. But then, they aren’t very good as boat anchors either. Cassettes are almost ideal as a low cost medium for storing data and for programs which are not used much. And they are ex- cellent as a medium for transferring programs. The cassette itself is much less costly than a disk. Its use cuts about $5 to $10 from the cost of a program—and that mounts up after a while! Also, once you load the pro- gram onto a disk for use, you can then put the cassette away in its safe plastic storage box until you foul up the disk copy. Disks can be zinged by almost any- thing, while cassettes are virtually in- destructible. The plastic box I store them in keeps out the dust and has enough room to quickly index the cassette. In Japan virtually all pro- grams are sold on cassettes. So what would it cost to have kept the small circuits needed to interface a cassette recorder in the Apple? I ap- preciate the fact that Apple pio- neered the microcomputer floppy disk—but this may have been going a bit too far. Of course, by not permit- ting further use of the cassette, they did force people to think about disks with a vengeance. But it also wasted a lot of customer money. Another area given too little shrift by many manufacturers, including Apple—and certainly Radio Shack— is cooperation with computer maga- zines. There are many of them, at first appearance; but when you re- member that few buyers of new desk- top computers fail to ask a friend who already has a computer about their purchase, it’s clear that virtually every new purchase of a computer depends, to some degree, on how ex- perienced computerists view the system. We'll see what happens with the Lisa; but unless the world has changed in the last year or two, it is going to be like pulling teeth to get a review of Lisa for our magazines, Yet, we have over one million readers who will probably have more to-say about the success of the Lisa than any Apple ad in Time magazine or on television. Let me ask you a question. You have a computer. Is there a week when someone doesn’t ask you for a ‘‘Computer magazines are being almost totally ignored by our industry.’’ recommendation about computers? With me it is an hourly question, not a daily one. Do I recommend a com- puter I don’t know about? Don't be silly. No more than you do, The For- tune computer may be great, but I've never had my hands on one—or talked with anyone who has—nor have I read much about it in comput- er magazines. So I ignore it when asked about it. Many of you talk to local groups about computers, drawing on what you've learned from your own com- puters and on what you've read in computer magazines. Yet computer magazines are being almost totally ig- nored by our industry. A recent count of firms manufacturing desktop com- puters was well over 250, yet most material in computer magazines revolves around a dozen systems. Many marketing managers are not doing their jobs well. They don’t seem to understand what is going on. 8 Gider April 1983 More Apple II owners choose Hayes Micromodem II than any other modem in the world. Compare these features before you buy. You should. It’s your money. Thousands of other Apple 11 owners have already com- pared, considered, and are now communicating — all over the U.S.A.— with Micromodem II. The best modem for the Apple IL. The most modem 4 for your money. ES Acomplete data communi- cation system. Micromodem I] is not "base priced” plus necessary “options.” It's a complete, high-performance data com- munication system. The printed circuit board fits — quickly and easily — into your Apple II, eliminating the need for a serial interface card. And the Microcoupler™ (included) connects the Apple II directly to a standard modular telephone jack. Auto-dial and -answer features are built in. Operation can be full or half duplex, eg ~~Microcoupler witha transmission rate of 300 bps. And it’s Bell 103 compatible and FCC approved. Now there's Hayes Terminal Pro- gram, too! Developed by Hayes speci- fically for Micromodem II, this new Terminal Program allows you to access all the great features of your modem ina matter of seconds. With it, youcan use your CP/M" DOS 3.3 or Pascal for- matted disks to create, send, re- ceive, list and delete files. Hayes Terminal Program is acomplete, stand-alone disk. And because it's menu driven, you can choose from a wide variety of options to set your communication param- eters — as well as change hard- ware configuration — directly from the keyboard. It even allows you to generate ASCII characters that are normally not available from Apple Your Apple'll Hayes keyboards, further extending your capabilities. Incoming data can be printed (on serial or parallel printers) as it’s displayed on your screen. Micromodem II is available with or without the Terminal Program. Buy your modem by itself, or optionally pack- aged with the Terminal Program disk and user manual at extra cost. The soft- ware is also sold separately, for those who already own a Micromodem II. If you're ready to communicate with other computers, to access infor- mation utilities, time-sharing systems, or use bulletin boards, then you're ready for Micromodem II. Come on. Compare. Consider. Then buy. Micromodem I] is already the best-selling modem for the Apple Il. And Hayes’ new Terminal Program makes it better than ever. Available at computer stores nationwide. Hayes Microcomputer Products, Inc. 5835 Peachtree Corners East Norcross, Georgia 30092 (404) 449-8791 just isnt the same without Hayes Micromodem II' MMicromodem II and Microcoupler are trademarks of Hayes CP/M is a registered trademark of Digital Research, In Circle 51 on Reader Service card. NEW! Terminal Program from Hayes! Products, Inc. Apple is a registered trademark of Apple Computer, Inc. a iter Products, Inc. Sold only in the U.S.A. Fermentations by George M. Engel hat do you do when you get those silly questions, like, “What does it do. . . besides games?” I stifle my anger and launch the doubter into two uninterrupted hours of alf music, adventures, math tutorials, DNA molecules, flight simulators, graphics demos, word processors, VisiCalc, VisiPlot, and so on, ad infinitum. The parting com- ments are always, “I didn’t realize,” or, “I thought it was only for games.” ONLY for games? That’s why I bought my Apple. I have many other programs, of course, but I’m a Gamer first and foremost. Why be ashamed to admit it? But, let’s go back a bit... Remember when you first learned math and spelling? It was never fun and exciting. Come to think of it, it was darn hard work. Think what you could have done if you'd really en- joyed it—if they had made a game out of those subjects. Today, you put your children in front of your Apple with a good game and look what they In Defense of Gaming learn: spatial relationships, eye-hand coordination, and so on. What else did we forget? The most important thing—responsibility. On the computer, children are responsi- ble for their own actions. Their mistakes are their own, They can't blame anyone else. They’re not working as a team, they’re working as individuals. Our colleges train students to enter the labor force. “Don’t be different,” is the message. “Don’t find the -creative way to do things, you’ll em- barrass others.” Our colleges prepare students to find jobs. European universities train students to make jobs! Let's train our kids as in- dividuals, not as a team; to assume responsibility, not disseminate it; to nurture creativity, not stifle it. Games like “Cartels and Cut- throats,” a business simulation, bring out this wonder called creativity and force you to think as an individual. You have to. It’s your business. Adventures, strategy simulations and war games all make you think. They stimulate the reasoning process, and make it fun to learn, to create, to as- sume command and to assume re- sponsibility, That’s life, my friends—learning to cope with the world on its own terms. All we can do for our children is provide the tools and the stimulation to succeed. As Apple owners we have the tools. They are expensive, but, as the slogan goes, if you think educa- tion is expensive, consider the cost of ignorance. Your kids will have fun learning on the Apple. Encourage and applaud them when necessary. Then they'll take over, We are train- ing them to take over, aren’t we? The world belongs to our children and the next decades are theirs. We're only the caretakers. That’s as simple as I can make it. You're remembered in this life by how well you play the game. I hope my thoughts help the next time you're asked, “But what does it do?” As always, I can’t wait to be asked—and neither can my sons! ll Circle 245 on Reader Service card. TOLL FREE 1-800-841-0860 OKIDATA EPSON | ABN oiniconons PRINTERS PRINTERS WHEEL . DISCOUNT DISCOUNT DISCOUNT ‘pees ERICED FROM aw PRICED FROM PRICED 3348 | Se 5438 — Sai] $559 FROM ML-80 MX-80 / #50005 We carry the full Epson, a MANAGEMENT SYSTEMS —FRS-80 WRITE FOR Okidata, & Smith Corona Passer oivltlon Dart te 3 FRANKLIN FREE product line. | (to, 912.977.7120 Cairo, Georgia 31728 Crcommodore PRICE LIST 10 Cider April 1983 ‘LOOK WHAT YOU, haos in the bakery s you contend with “Best graphics ‘ever éantankerous in a hign vol onveyor belt in an See if you can sneak past the * ffort to e~ pies. security guards in’ this best-seller. : , heel NEW RELEASES * * Run a gavntlet of deadly The criminal element oe ae ok. alien sharpshooters. . ‘ ' ‘ 1 ° * .* We believe games should be fun and that the price of games siouldn't dampen that fun. -The growth of the market over the past couple of Years leads us to believe that $19.95 may work now as a reasonable game price, so we' re trying it for the next six months, and if we're right, longer. This pol ploes not just apply fo new qanieer but to ALL our games, including ourpast and eutignt best-sellers!@ur bet is that ~ we'll sell more and that the increased sales will offset the decreased income per product If so, moye | people get to play our games, and we still make enough to keep developing newer and b ilerssoftware. As*our customers know, at Penguin Software we take a great deal of care and pride in our, products. This change i in our pricing in no way affects our standards of quality. We pioneered the removal of copy- protection from spplications software last year iman effort to give you a better product. This year we are ‘Wain to lead the way in putting the customer first. ~~ * Can you round them up? cise 23 on Reader oS card, penguin software ........... (312) 232-1984 830 4th Avenue, ‘Geneva, IL 60134 Dealer, Hotline: (800) 323-0116, retailers only, please. [Available at yosir localicompater vstoreMDealer'st ‘and distributor inquiries welcome. Visa/MasterCard accepted. INTRODUCING MONEY BUSINI IBMES: WORTH ITS WAIT Leash you a p gram a little later, ifwecan a whole lot better. And: Money Business/1 M.S. is a whole lot better. While some competitive programs were willing to make compromises in order to make quick sales— we resisted the temptation. We've invested thou- sands of hours in research and development to make LMS. thoroughly professional, reliable, and so easy to use that it doesn’t take a computer fanatic to run it. That type of usability takes time to perfect, but it’s worth it. The Gold. Money Business/LM.S. won't Cost you a King’s ran- som. At only $495.00 retail, it costs several hundred dollars less than competitive programs which, quite honestly, are neither as easy to use or as powerful as LMS. You save money right from the start, since no costly training period or programming expertise is required. So LMS. can be up and working in just a few hours,saving youeven more money as you enjoy higher productivity through better information manage- ment. The Works. Exactly what does Money Business/1M.S. do for you? Briefly, you can create, manipulate and maintain files of data quickly and easily. You can easily create a flow chart of your entire operation ina few 8943 Fullbright Avenue, Chatsworth, CA 91311 (213) 709-1202. ly front of you whenever you n fc Impressed? There's more. LM.S. requiresabsolutely -‘nosorting. It automatically putsall data into place— so you have instant access, saving countless hours _ of inputting data! LMS. can also revise existing files without affecting data that's already entered. Italso interfaces with Palantir, Wordstar, Magic Wand and many other popular word processing programs. _ The Close. Money Business/ IMS. manages your information effec- tively, efficiently and effortlessly. Anditinteracts with the entiresystem of DATAMOST Money Business modules, including General Ledger, Accounts Receivable, Ac- counts Payable, Pay- roll and Financier. Six interactive pro- grams in all—tested and proven to perform for you. Don’t Wait. Put Money Business/LM.S. to work for your business today. You'll be on your way toown- ing the finest total business program package available. Money Business/LM.S. $495.00 at your computer/ software dealer, or from: The Specifications. Money Business modules run on any computer, including Apple* which uses CP/M* or MP/M*.48K, at least one disk drive and an optional printer are required to operate the system. DATAMOSTE Circle 36 on Reader Service card. Cider inCider editorial offices Pine Street Peterborough, NIH 03458 603-924-9471 MANAGING EDITOR Linda Stephenson SENIOR EDITOR Paul C. Quinn ‘TECHNICAL AND REVIEW EDITOR Hartley Lesser CHIEF COPY EDITOR Peg LePage NEW PRODUCTS EDITOR Tom Woods NEWS EDITOR John P. Mello, Jr. ASSISTANT EDITOR Joan Witham PRODUCTION EDITOR Susan Gross LAYOUT EDITORS Joan Ahern, Bob Dukette, Sue Hays, Laura Landy, Anne Vadeboneoeur PROOFREADERS Peter Bjornsen, Harold Bjorsen, Vinoy Laughner, Louis Marini Problems with Subscriptions: Send a descrip- tion of the problem and your current and/or most recent address to: inCider, Subscription Department, PO Box 911, Farmingdale, NY 11737. Change of Address: Send an old label or a copy of your old address and -new address to: in- Cider, PO Box 911, Farmingdale, NY 11737. Please give eight weeks’ advance notice. Microfilm: This publication is available in mi- cernform from University Microfilms Interna- tional. United States address: 300 North Zeeb Road, Dept. P.R., Ann Arbor, MI 48106. For- eign address; 18 Bedford Row, Dept. P.R., London, WCIR4EJ, England, Dealers: Contact Ginnie Boudrieau, Bulk Sales Manager, inCider, Pine Street, Peterbor- ough, NH 03458. 800-343-0728. “Manuscripts are welcome at inGider. We will consider pub- lication of any Apple material. Guidelines for budding authors are available. Please send a self-addressed envelope and ask for “How to Write for inGider.” inCider is pub- lished monthly by Wayne Green Ine. Entire contents copy- right 1983 Wayne Green Inc. No part of this publication may be reprinted, or reproduced by any means, without prior written permission from the publisher. All programs inCide Out What’s New This Month? \ K ] elcome to the April issue of inCider. In our cover article, Harry White describes several file pro- tection techniques that are easy to im- plement. A friend of the author, a school teacher, needed a system to deter the mischievous tamperings of students. It seems that a student had left an unusual message for his instruc- tor in an attendance file program. Both hardware and software schemes are discussed, so you can tailor protec- tion to individual needs. Although the protection techniques won't guarantee security, they’re sure to deter all but the most determined vandal. If you’re wondering if most of your software will run on the new Apple le, read our technical editor’s IIe soft- ware compatibility study. Over 250 pl ;, from “A Steller Trek” to “Zork I,” have been tested. The study includes some new programs, a few 3:2 DOS favorites, and a number of old but unforgettable classics. Our guest editor this month, George Engel, isn’t afraid to admit that he purchased his Apple mainly for recre- ational purposes. The author is a Gamer at heart, and he points out that games can develop more than just eye- hand coordination. The value of com- puter games, especially for the young, is a controversial issue. We'd like to hear how you feel about the issue. If you feel strongly one way or the other after reading Mr. Engle’s article, please write down your thoughts and send them to inCider. In the Applesoft Adviser, Dan Bish- op continues his tutorials for the Basic programmer. Even an experienced programmer is likely to find something of interest. And for those who are in- terested in the nuts and bolts of pro- gramming, a new column, written by none other than Randy Hyde, author of the LISA compiler, begins this month in inCider. Greg, Glau’s Bent on Business col- umn describes a novel approach to em- ployer-employee communication. Glau’s formula allows an employer to graphically show employees how their performance is helping or hurting the company. It also gives employees a general evaluation of the company’s overall performance without revealing actual profit amounts. Bert Kersey of Beagle Bros, formerly a bored, free-lance graphics designer, tells of his early fascination with com- puter programming; and in Practically Pascal, John Stephenson tells how to create a useful address book in a lan- guage that is not as complicated as is often thought. This month Paul Raymer introduces a brand new operating system for the Apple, affectionately called CON:DOS. Individual units within the DOS aid in understanding the pro- gram and are also quite innovative. Fred Huntington explores the current mis-state of user documentation, and Don Fudge digs deeper into those col- orful mysteries known as Apple graphics. Whether you're a novice or an ad- vanced computerist, we hope you en- joy the April issue of inCider. And next month we'll be featuring a program that will help you enjoy the Indianap- olis 500 at home. Ml are published for personal use only. All rights 14 Gider April 1983 Color for the Price of Black and White e Built by Seikosha, the oldest manufacturing company of the famous Seiko group—providing precision products since 1892. Transtar - Box C-96975 Bellevue, Washington 98009 Circle 265 on Reader Service card. Circle 174 on Reader Service card. MicroSpooler Saves Time MicroSpoolers mean an end to waiting. The MicroSpooler stores data and feeds it to your printer as fast as it can handle it. You don't lose valuable computer time waiting for the printer to do its job. Easy to install. Easy to use. Easy on the budget. These stand-alone MicroSpoolers can be installed in- line between virtually any printer and any computer , including Apple II, II. Features: @ 16K memory (user expandable to 32K or 64K) ¢ Status readout ¢ Internal power supply ® Vertical mount configuration © Indepen- dently selectable baud rates and handshaking ¢ Satisfaction guaranteed © Priced from $199.00 Praca, MicroSpeoier UFFER/ INTERFACE Send or call toll free for literature on our complete Spooler lines. CONSOLINK CORPORATION Dept. 2-45 1840 Industrial Circle Longmont, CO 80501 (303) 651-2014 800-525-6705 16 Gider April 1983 Letters Super Stereo Update I was interested in Phil Roybal’s article on phonograph pickup-arm tracking error (January 1983) because the results he quoted matched closely a similar analysis I did several years ago while designing my own arm. There is, however, an important ambiguity in the article that could re- sult in a number of worried audio- philes and perhaps even some dam- aged equipment. The important point to add is that no manufacturer, to my knowledge, still makes a straight arm for which the equation for underhang can be used. This equation és correct, but only for an arm in which (1) the axis of the stylus intersects the axis of the arm pivot and in which (2) the position of the arm pivot is fixed. All of the servo-controlled parallel- tracking arms satisfy condition 1, but in these arms the pivot moves in order to maintain essentially zero tracking error. Because the pivot moves, the term underhang, as defined in the ar- ticle, has no meaning. Perhaps there were arms in 1941 (when the refer- ence quoted by Roybal was written) that satisfied both conditions ] and 2. However, all modern fixed-pivot arms (even those in cheap toy phonographs) are offset. In other words, all modern fixed- pivot pickup arms should be set up with overhang as calculated from Mr. Roybal’s second equation. Straight arms should not be short- ened or repositioned to achieve un- derhang. R.T. Chilcoat, Ph.D. State University of New York Syracuse, NY DOS Depression Update A number of readers sent in this simple solution for DOS Depression (Jan:136). D$ = CHR§¢(13) + CHRS(4) Larry E. Nix Martin Sandry Craig E. Daniels F. Kuechmann Graphics Tips Wanted I just purchased your premiere is- sue of inCider and I have thor- oughly enjoyed experiencing the be- ginning of a fresh young magazine. The articles are thorough and easily understood so that implementation of the programs is easy. I enjoyed your Apple/80 article and I look for- ward to entering the data onto my diskettes and playing the program on my system. Being a graphic designer and a new Apple owner (Apple II) my interest lies in the computer graphics area, I hope your readers {including myself) will contribute new tips and techniques in the graph- ics field (not just game symbols) and real graphics applications without elaborate hardware and expensive software. Tom Milligan San Jose, CA Printer Help Needed T have owned an Apple II Plus sys- tem for only a few months and have found it to be able to do amazing, complicated things, but I haven’t been able to make it do something I consider quite simple. I have the following equipment: Apple II Plus with one Disk II drive, Monitor III, and a NEC PC-8023A dot ma- trix printer with a Microteck par- allel card. The problem is in introducing printer commands in a copy-protect- ed program. I purchased a PFS soft- ware program (Software Publishing Corp.) to do filing, making name and address lists, ete. The program prints nicely but only in single columns. I want to be able to fill the whole page with two or three columns with the listings. For example, if I were print- ing an address list I would want about six names and addresses at the left margin, six in the center of the page and six on the right side (alpha- betized). 1 have written Software Publishing and they tell me it can’t be done. Can anyone help me? H. Paul Bruns Royal Oak, MI Compatible color . . monitors ».. for demanding graphics or text display. For high resolution (660H X 240V) color graphics, you can't beat the Amdek Color-ll Monitor. And if you're looking for economy, the Color-IIl Monitor with 260H X 300V resolution is a superb buy. Both monitors feature RGB video input for computer control- led color ... and Amdek’s easy-to-install Digital Video Multi- plexor (DVM) board permits interface with the most popular 80 column boards. Just call, or write for full details. 2201 Lively Blvd. ® Elk Grove Village, IL 60007 (312) 364-1180 TLX: 25-4786 Color-Il Monitor has RGB input and 560(H) X 240(V) line resolution Color-IIl Monitor has RGB input and 260(H) X 300(V) line Resolution Digital Video Multiplexor (DVM) assures color graphics interface with most popular 80 column boards, such as: Videx ‘“Videoterm’, Advanced Logic “‘Smart-term”, M&R “SUP 'R’ TERMINAL”, Bit-3 Computer Corporation “FULL VIEW-80", and the ‘‘Doublevision” boards Circle 95 on Reader Service card Applewatch edited by John P. Mello, Jr. HARD WA RJ: ERE SE Lisa Wi appropriate fanfare, Apple Computer Inc, un- veiled its Local Integrated Software Architecture system, known for months as Lisa. The product of $50 million and 200 man-years of development, Lisa is a software-hardware powerhouse aimed at the office environment. For a tad under $10,000, the Lisa package includes: @A Motorola MC68000-based_mi- crocomputer with 32-bit internal ar- chitecture and 16-bit external data- path; @ Three interface ports, two serial and one parallel; @ A 12 inch, black-on-white, high-res- olution (364 lines x 720 dots) monitor; @ One megabyte of RAM; @Two Apple 871, 5.25-inch disk drives providing 1.7 megabytes of formatted storage; @ ProFile, Apple's 5-megabyte hard disk; and @Software for word processing, spreadsheet analysis, graphics, graphic design, database manage- ment, and project management. And if all that didn’t make Lisa “sexy” enough, it’s designed to reverse the slave-computer relation- ship many users have had with their Wundermaschine. “Lisa embodies a radical change in how users work with computers,” the vice president and general manager of Apple’s personal office division, Apple introduces state of the art in user friendliness. John Couch, said in a statement. “Conventional computers created obstacles for those who wanted to make their jobs more efficient. We used progress in microtechnology, plus advances in software technol- ogy, to remove many of those ob- stacles and to make a computer that really is simple to use.” According to the statement from Apple, Lisa’s screen shows simple pictures of documents, folders, and other familiar objects in a typical of- fice. A palm-sized device, called a mouse, is used to point to and manip- ulate the items, The user controls Lisa intuitively by pointing at and selecting the sym- bol for file folder, memo pad, waste- 18 Cider April 1983 MICROCOCCUSeMICROLITER micrococcus, mi kro kok’ us, n. a microscopic organism of a round form. Microcomputing, mi’ kro kom put ing, n. (Gr. mikros, small, and L. computo, to calculate.) The multi-system monthly journal for computer enthusiasts, containing all the information needed to turn your microcomputer into a powerful machine. Includes dozens of new pro- grams, articles on innovative computer applications, buyer’s guides, new programming techniques, accurate reviews of hardware and software, complete coverage of new products, tips on your system’s hidden capabilities, hardware modifications, tutorials, utilities, book reviews, industry news. Plus features on computers in business, science, education and games. Written in understandable language by experts in the field of com- puting. Special emphasis is placed on the Apple’, Atari, Commodore, Heath and IBM systems, but not to the ex- clusion of other systems. (Ed. note—A one year subscription to MICROCOM- PUTING is only $24.97. Call 1-800-258-5473 Or send in the coupon below (or the attached card.) microcopy, mi’ kro kop i, n. A photographic copy of printed material or photographs. . . MICROCOMPUTING * The First Word in Computer Publishing. *Apple® is a registered trademark of Apple Computer, Inc. rc | YES! I want to get the First Word in Computer Publishing. Send me 12 issues of MICROCOMPUTING for only | | $24.97. O Check enclosed O MC O VISA O AE O Billme | | Card# Exp. Date | | Interbank# Name | | Address 2 | | City State. Zip. 3 | | Box 997 ‘Canada & Mexico $27.97, 1 Year Only, U.S, Funds | MICROCOMPUTING s Foreign Surface $44.97, 1 Year Only, U.S, Funds Drawn on U.S. Bank Farmingdale, NY 11737 Allow 6-8 weeks for delivery. i Sarna. ee as ee a 23) April 1983 @ider 19 Applewatch: basket, or other familiar objects. Once the object is selected, it’s used like its real-life counterpart. A file folder can be opened and the con- tents revealed; documents can be re- filed, copied, taken out and changed, put into a new file, or thrown away. The basic functions in all six of Lisa’s integrated software packages operate in the same way. ‘Transferring information from one application to another is easy with Lisa, Apple said. When writing a cost analysis report, a user can quickly shift from word processing to spread- sheet analysis. He can even “cut out” the spreadsheet and “paste” it into his report. The software packages with Lisa include: @LisaCalc, a spreadsheet program for handling budgets, forecasts, and other row-and-column models; @ LisaWrite, a word processing pro- gram, including a feature allowing users to choose bold, italic, and un- derlined text via the mouse; @LisaGraph, a graph display pro- gram allowing spreadsheet data to be displayed as bar, line, or mixed graphs; @ LisaDraw, a graphics program al- lowing users to enhance reports by drawing visuals for them; @ LisaProject, a time-management program permitting a user to keep track of complex deadlines; and @LisaList, a database management program. “ By allowing Lisa to support the CP/M and Xenix operating systems, and run Basic, Pascal, and Cobol, Apple hopes to encourage indepen- dent software vendors to write pro- grams for Lisa. Late this year, Apple will also be providing independents with a Lisa Applications Develop- ment Toolkit to help them develop antepyated programs for the new machine. Lisa and a communications pack- age for it, LisaTerminal, are expect- ed to be available this spring. Foreign language versions of Lisa will be in- troduced worldwide this summer. And networking packages for Lisa will be available late this year. WICO Corporation Command Control Joystick Modified grip handle and two firing buttons. HLS) ieee an Winter Consumer Electronics Show For Apple users enough new products to crash the senses. By Robert G. Fisher Special to inCider y any yardstick, the 1983 Win- ‘ter Consumer Electronics Show in Las Vegas was a rip-roaring suc- cess. And, for anyone involved with the distribution, marketing, retailing or use of Apple microcomputer prod- ucts, it was overwhelming. Officially, 78,126 persons visited the 1050 exhibition booths during the four-day show, breaking all at- tendance records both for the semi- annual show and for Las Vegas, which considers itself the convention capital of the world. Actually, the number of visitors was far in excess of the official tally; indeed, it may very well have been half again that many. Convention officials explained that local busi- nesses and guests were not included in the official count. And, because WCES passes were limited, daily show access badges were freely passed around by some offical dele- gates to their friends and “groupies” who wanted to find out what the future of the exploding world of electronics has to offer. The vast number of products for Apple systems was exhausting to many attendees. On display were a myriad of innovations and improve- ments in areas of hardware, soft- ware, peripherals, furniture and ac- cessories. By far, the largest group of soft- ware exhibitors at WCES were the producers of home video games, many Apple compatible. Datasoft Inc. had one of the largest such displays, again showing its ex- pertise in adapting its software not only to the Apple, but to a dozen other microcomputer systems as well, Similarly, Datamost Inc., forme in early 1982, had a giant display, introducing five new computer game cartridges. Datamost expects to log $10 million in software sales this year. Scholastic Inc. also debuted a new line of children’s software, scheduled to be available to the public in the spring under the Wizware label, the latest addition to a full line of that firm’s children’s communication products. Six ‘am titles, compat- ible with Apple II Plus, are being made available this spring, including Microzine, the first computer maga- 20 Eider April 1983 ‘Applewatch zine for children, and other fun video learning games. In the peripheral area, Star Mi- cronics Ine. of Dallas introduced a new thermal printer, priced to retail for $199, that promises to pierce that market. Brother International displayed its new electronic compact typewrit- er line, the Correctronic 50, capable of doubling as a microcomputer printer terminal by use of a built-in interface port. Disewasher of New York intro- duced a disk drive cleaner, designed to remove all debris and keep disk drives working at optimum capacity. It is non-abrasive and_ utili: a unique fiber grid cleaning system and “perfect path” technology to thor- oughly dislodge and collect foreign matter from sensitive drives. The cleaner is available in 5Y%-inch and 8-inch formats. A new WICO Corporation Com- mand Control joystick, first seen at the show and interfacing with the Apple II and other personal comput- ers, is being made available. Equipped with a modified grip han- dle and two firing buttons, plus a selection switch for centering/non- centering option, it will retail through Apple outlets at $69.95. Both Maxell and BASF and other tape manufacturers competed for at- tention at the show for their respec- tive segments of the tape and floppy disk market. BASF exhibited its Qualimetric FlexyDisks, first introduced in Octo- ber 1982, and claimed to be the first manufacturer of 100-percent, error- free floppy disks with a lifetime warranty. Maxell Corporation delegates proudly demonstrated their revolu- tionary 3-inch Compact Floppy Disk (CFD), along with their com- patible (and same recording capaci- ty) 5Y%4-inch double density, mini- floppy disk. Scholastic Inc. of New York Six new programs compatible with the Apple Plus. At a computer seminar during the show, leading industry spokesmen noted that, while computer and computer-related sales were up over the preceding year generally, those sales still were not as much as origi- nally projected, due in great part, they said, to the faltering economic situation. Nevertheless, most executives fore- see an economic turnaround that will benefit the personal computer indus- try and its spinoffs, Even as the WCES was drawing to a close, those industry representatives were plan- ning for what they expect to be an even bigger and better show next June in Chicago. [as you step onto the porch, the pa | end the radio go dead. It's so dork you can borely r H sign vhich says UHAT DD YOU UANT To DO? 1 Ring bell 2 fnepk oround side of house ond ook in @ vindow. Tree i oR 2: Jam | a William Tell Overture A new Taiwanese micro sporting a 6502 and Z-80 intends to take on Apple. By Robert Fisher Special to inCider A new microcomputer is being introduced into select retail areas this spring that—if for no other reason than its price tag—promises to make a solid impact into the personal computer market, Aptly named the William Tell, manufactured by Star Micronics Inc. of Dallas, TX, it will retail for an ex- tremely competitive $999.95. It was briefly shown at the 1983 Winter Consumer Electronics Show in Janu- ary and will make a repeat appear- ance at the June CES in Chicago. David Wooldridge, consultant to Star Micronies, describes the William Tell as “basically, a 64K system, CPM-compatible, with a Z-80 micro- processor. And, so it will be compati- ble with Apple systems, it also carries a 6502 processor. “We're carrying both sides of the street,” Wooldridge said. He pointed out the new microcomputer also has a universal power supply (110V- 220V, 50- or 60-cycle) and can be operated anywhere in the world. Additionally, Wooldridge ex- plained, it has a full color output for monitors and is equipped with full graphics, And, for those who want a personal computer ‘providing home entertainment, the William Tell has April 1983 @ider 21 Applewatch a port to plug in a joystick for video game playing. Asked whether the product name, William Tell, had any significance, Wooldridge smiled and said, “We imply that another product is a target, but we never come right out and say so.” The William Tell is manufactured with two 54-inch disk drives and has a 10-key pad. Upper- and lowercase character sets are built into the sys- tem, and, because it is CP/M compat- ible, it will make an 80-column print- out. “With the William Tell, Star Mi- cronics is putting it all on one card,” Wooldridge said. “It is especially suitable for printout operation with Star Micronics’ Gemini 10 and Gem- ini 16 printers, as well as Star's new thermal printer that retails for $199,” he added. “It’s an excellent system that can be taken home for a very inexpensive amount of money,” Wooldridge said. “For about $1500, a user can get the William Tell, a good monitor and a printer,” For those who do not want a disk drive, the William Tell also has cassette recorder connection ter- minals. Marketing of the William Tell is based in Dallas. “We're trying to select some of the distributors with whom I’ve been doing data process- ing business for some 20 years—dis- tributors who have proven track records,” said Wooldridge, a former National Cash Register executive. “We're getting the distributors that really reach the market, and we're giving some points that will let them and the retailers make some money, without relying totally on followup sales of peripherals and software, “It's like a crap table,” said Wooldridge during a CES interview in Las Vegas, the gaming capital of the world. “You can’t bet on a come. And that’s what you're betting on when you rely on selling software to make a profit. If you can’t make the subsequent sales, there's no way you can justify the floor space, warehous- David Wooldridge. consultant to Star Micronies of Dallas “We imply that another product is a target, but we never come right out and say so.” photos by: Robert Fisher “For about $1500, a user can get the William Tell, a good monitor and a printer.” ing, salaries and overhead for a few dollars a unit. “We're doing our best to pick -distributors that will maintain our price structure. Of course, that can- not be guaranteed, and we're not so naive as to think that. “We're picking distributors that get as close to retail as they possibly can, but people who are not dis- counters. There's not anything wrong with discounting, except a tendency to have a problem one way or another; discounting drives the retailers down.” At the June CES in Chicago, Star Micronics intends to have still another new product: a fully port- able, disk-driven microcomputer with a 9-inch green-phosphor screen that will also carry a 6502 Apple- compatible board. Prototypes of the portable unit were produced in January, and the firm approved the design of the case at that time. Initial distribution will begin in May, and dealers will see it in full bloom at Chicago’s CES, Wooldridge said. 22 Eider April 1983 BUY SOME TIME FOR ‘169 Time is money. You have a computer system because you know that it saves you money by simplifying procedures and reducing time normally involved in your work. Time is an important resource which should not be wasted. You are wasting valuable time if you ever wait for your printer. No waiting. Now with Microfazer by Quadram there is no more waiting. Microfazers are inexpensive universal printer buffers which any computer user cannot afford to be without. Any computer—any printer (or plotter!), whether parallel or serial. Microfazer receives information from the computer, at ultra high speeds causing the computer to think the printer is printing just as fast as the computer can send. Microfazer holds the information until your printer can handle it, and then sends it on. Special version for attaching directly to the popular Epson printer. ie More copies. Microfazer is equipped with a copy feature allowing additional copies of the buffered information—from one to as many as you want—with the mere press of a button. When you need your information repeated, for whatever reason, it’s always right there—inside Microfazer. Microfazer™ stack. Microfazer canbe stacked with popular modems or other peripherals. Some models can plug directly onto the back of your printer. Install it in less than 60 seconds, and choose the amount of buffer memory you need—8K, 16K, 32K, or 64K. One model even comes with up to 512K! You may use several Microfazers in series to create just what's right for you. Take data in from a serial computer and out to a parallel printer. Or in from a parallel computer and out to a serial printer. Microfazer is just as flexible as you need it to be. Low price. Only $169 for 8K of buffering, $189 (16K), $225 (32K) and $299 for a full 64K. Serial-to-Parallel, Parallel-to-Serial and Serial-to-Serial models have slightly higher prices. QUADRAM CORPORATION 4357 Park Drive/Norcross, Ga. 30093, (404) 923-6666 The Applesoft Adviser by Dan Bishop I: the previous article in this tu- torial series covering the use of Basic, I dealt with the principal loop- ing structure provided by Basic, the For/Next loop. Data input using the Read command in combination with Data statements was also introduced, along with the Peek/Poke commands and how these two commands could be used to allow the programmer the flexibility of restoring the data pointer to any desired position in the data list without having to always re- store to the beginning of the data list. In this article, I will deal with the If/Then statement and the use of sub- routines. I hope that even the veteran Basic programmer will spend some time with the material in this article, for I anticipate that some of the con- cepts that I will present may not be widely known or used. I will intro- duce the concept of structured pro- gramming and show how the If/ Then/Else, and While/Do, the Re- peat/Until, and the Case/Of struc- tures found in such languages as Pas- cal can be duplicated in Applesoft Basic. Conditional Branching In Basic—If/Then Without the capability to make decisions based on elementary rela- tionships and logic, the computer would be a very ineffective tool. As it is, the computer can make simple comparisons and use the results of such comparisons to branch to differ- ent sets of instructions. Although the result of any comparison must be either “true” or “false” in a strictly logical sense, the flexibility this gives the computer is awesome. Numbers or mathematical expres- ‘Address correspondence to Dan Bishop, Custom Comp, PO Box 429, Buena Vista, CO 81211. sions can be compared for equality, and the result will be either “true,” meaning “yes, these two numbers (variables, expressions) are equal” or “false,” meaning “no, these two are not equal.” Variables are most com- monly used in these comparisons, and it is, of course, the values that these variables represent that are be- ing used by the computer for the comparison. The principal Basic instruction that directs the computer to make such a comparison is the If/Then statement. The general format for this instruction uses one of the follow- ing forms illustrated in Table 1. In the statements shown in the table, the symbols separating the two expressions are referred to as “rela- tional operators.” In the order shown, they are read as follows: “equals,” “does not equal,” “is less than,” “is less than or equal to,” “is greater than,” and “is greater than or equal to.” Expression 1 and expres- sion 2 may be simple variables or con- stants, as in the following: IF A=45 THEN. IF XY> A3 THEN... The ellipses following the word THEN represent any valid Basic Conditional Relationships and Subroutines IF expression 1 = expression 2 THEN. .. IF expression 1 <> expression 2 THEN. .. IF expression 1<_ expression 2 THEN. .. IF expression 1< = expression 2 THEN. .. IF expression 1> expression 2 THEN... IF expression 1>= expression 2 THEN. . . Table 1. If/Then forms. command or combination of com- mands separated by colons. They represent the specific set of instruc- tions that the computer is to follow should the relationship between the two expressions turn out to be true. If the relationship is not true, the com- puter will completely ignore all of the commands contained in that pro- gram line and will continue with the next program line. For example: 60 IF A=45 THEN PRINT “A EQUALS 45.";GOTO 80 70 PRINT “A DOES NOT EQUAL 45” 80 program continues from here. Notice that two commands are in- cluded following THEN in line 60. These commands are only carried out if expression 1, the value associated with the variable A, equals expres- sion 2, the constant 45. If A is not equal to 45, the computer will simply ignore these two commands and go on to line 70. The Goto command in line 60 is very important. Without it, for the case that A does equal 45, we would see the following displayed on the screen: 210 GOTO 470 120 IF AR > = BC THEN GOTO 220 130 beginning of instruction block for “false” 200 end of instruction block for “false” 220 beginning of instruction block for “true” 460 end of instruction block for “true” 470 program continues from here Sample listing 1. 24 Gider April 1983 ESOL wor HUNG” " Pits CAG WILLMAKE APE THE JACK OF ALL'TRADES FOR $129°°. Four applications in one. The Incredible Jack combines the convenience of a personal filer with the power of a calc package. It handles most word processing tasks with ease. Toss in the ability to sort and print mailing labels, and you have a totally integrated, suprisingly easy to use package that does most of what you bought your Apple for. Organize information your way. The Incredible Jack lets you arrange your information in “records” you design yourself using the computer displ: Each record may be as little as a mailin; label or as large as 60 sheets of legal sized paper. Word processing made easy. With a few simple commands you can master in minu letters, memos and reports. To help you edit, Jack lets you insert, celetes and copy portions of text all with automatic word wrap and flush right margins. The does away with the mind boggling control codes and formatting options of other word processing packages. Automatic decision making. Jack even allows you to build decison making logic into your file. With English language rules and a powerful IF THEN ELSE function, you can instantly calculate complex discount tables, commission plans, contract terms, or tax rates. See for yourself. Try Jack. (You'll need an Apple II Circle 282 on Reader Service card. you can create h 16K memory extension and 2 disks.) If you're not convinced it’s the best investment you've made since you bought your Apple, send Jack back in good condition within 2 weeks for a full refund. To order call: (800) 645-4513. For 516) 269-1120. To order (charge card # and e: N.Y. residents add 74% tax, and send to: Business Solutions, Inc. 60 E. Main St., Kings Park, N.Y. 11754. THE INCREDIBLE JACK.” GS WILLMAKE YOUR APPLE II THE JACK OF ALL TRADES The Applesoft Adviser A EQUALS45. A_ DOES NOT EQUAL 45. The GOTO command forces a jump over the instruction block that deals specifically with the situation occur- ring when the relationship is found to be false. This kind of approach begins to take on a leapfrog appearance when the instruction sets for the true and false situations become more compli- cated. For example, the situation in Sample listing 1 uses lines 130 to 210 to handle the instruction set to be car- tied out if the relationship between the two expressions is false, and lines 220 to 460 if the relationship is true. This leapfrogging, although en- couraged in Basic, brings nervous tremors to programmers who adhere rigidly to “structured programming” concepts, and we shall see later how to avoid this problem. But first let’s finish with the If/Then statement as it is interpreted by Applesoft Basic. String expressions may be com- pared, but you must remember that the strings are compared literally, character by character, throughout their entire length. The comparison is based on the ASCII code for each shorter string that is identical to the first portion of a longer string is taken to come before, or be “less than,” the longer string. The following com- parisons would evaluate as “true”: IF “APPLE” < “PEACH” THEN. .. IF “APPLE” > “APPLE” THEN. .. IF “DOG” < “DOGWOOD” THEN.. In the second example, expression 2 begins with the space (ASCII code 32), while expression 1 begins with an A (ASCII code 65). Although these examples use string constants, string variables could also be used in the comparisons. The literal evaluation of the rela- tionship between the two expressions can cause problems if the expressions represent real numbers that result from calculations, If the two expres- sions evaluate to two real numbers that are identical except in the last decimal place retained by the com- puter, they will be considered un- equal. This usually is not what the programmer desires, In such cases, it character being compared, and a, is best to evaluate the expressions as integers that contain the desired number of decimal places. For exam- ple, suppose that AB is to be com- pared with AM, both being real numbers that have been defined earlier in the program. If we desire the comparison to be carried out to the third decimal place, the follow- ing expression could be used: IF (INT(AB* 1000 + .5)) = (INT(AM * 1000 + .5)) THEN... In this case, the two real numbers are multiplied by 1000 to accom- modate the third decimal place. Each has 0.5 added to it, which rounds the number based on the fourth decimal place, and the resulting numbers are then converted to integers before the comparison, Of course, this approach will only work when the resulting integers are less than 32767, the maximum allowed value for integers. Finally, two other forms of the If/Then statement are equally valid in Applesoft Basic. When the only in- struction following the word THEN is a Goto command, the word THEN may be left out entirely, or the Goto may be left out. The following three statements are equally valid and per- form the same function. If RF > TD THEN GOTO 120 IF RF > TD GOTO 120 IF RF > TD THEN 120 Logical Operators The operators introduced in the previous section are called “relational operators” because the comparisons which use them are based on how the two expressions are related to each other. Applesoft also allows for use of three “logical operators,” AND, OR and NOT. Most commonly, these op- erators are used to compare the re- sults of two or more relational ex- pressions. As used here, a relational expression is simply the relational comparison of two arithmetic or string expressions exactly like the ex- amples presented above. But when we want the computer to carry out certain instructions only if two such relational expressions are evaluated as “true,” our program can be simplified using the logical operat- or, AND. Several logical relation- ships are illustrated below. IF (A=B) AND (A>D) THEN... IF (M$ = “CITY”) OR (S$ =“STATE”) THEN... IF (G% = 4) NOT ®% = 7) THEN... In the first of these examples, the instructions following the THEN (as represented by the ellipses) will be carried out only if both relational ex- pressions (A=B and A greater than D) are true. In the second example, the instruction set represented by the ellipses will be carried out if either or both of the relational expressions are true; in the third example, those in- structions will be followed if G% equals 4 and F% is not equal to 7. Obviously, the same results could be accomplished using two or more If statements that use only relational ex- pressions. However, as such relation- ships become more and more compli- cated, appropriate use of the logic operators will help keep the program more understandable and easier to work with. There is no practical limit as to the degree of complexity of these logical relationships, either, and they may be nested with the use of paren- theses. For example: IF (A=5 AND B=7) OR (A=6 AND B=5 NOT (D=3 OR D=4)) THEN... In this case, the instructions follow- ing THEN will be carried out either when A and B are5 and 7, respective- ly, or when A and B are 6 and 5, respectively, so long as D does not equal 3 or 4. Subroutines A subroutine is a set, or block, of Basic instructions that may. be thought of as being a “mini- program” that is separate from the “main program” but that is used by the main program whenever its instruction block is needed. The ap- pearance of the subroutine is no dif- ferent from that of the main pro- gram. Each instruction line has its own line number, just as in the main program. The only distinguishing characteristic is that the last com- mand in each subroutine must be the single word, RETURN. Subroutines may appear anywhere within a program. However, if they 26 Cider April 1983 FRANKLIN'S BAKER’S DOZEN! ganas Extras can more than double the price of your per- sonal computer. 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The Applesoft Adviser. are placed within the body of the main program, and are not also being used as part of the main program, a GOTO ##### must be placed im- mediately before the first line of the subroutine. This causes the main pro- gram to jump over the subroutine. The line number used in the Goto command corresponds to the line that follows the subroutine’s Return command. The subroutine itself is called by the main program whenever the block of instructions that it contains is needed. As soon as the computer en- counters GOSUB #####, it stops the line-by-line sequential execution of program instructions, sets a pointer to the command immediately follow- ing the Gosub statement, and pro- ceeds to the line number specified by the Gosub command. This line number is, of course, the first line in the desired subroutine. Line-by-line sequential execution of the subroutine’s instruction set is then carried out until the computer encounters the Return command. The computer then jumps back to the main program to where the pointer was set and begins executing the main program lines again. Subroutines may be nested several layers deep. That is, the main pro- gram may call a subroutine which itself uses a subroutine, etc. In each case, the computer sets a marker to the statement following the Gosub command and jumps to the specified subroutine. Each Return encoun- tered sends the computer back to the appropriate earlier subroutine, until the last Return sends it finally back to the main program. There is a limit to the degree to which subroutines may be nested. The computer has only a certain amount of memory reserved for the Return pointers, In the case of Apple- soft, this limit is 25. Should the limit be exceeded, the computer will re- spond with an Out of Memory Error. In this case there may be plenty of memory left for program instructions and variable storage; the Out of Memory refers to the “stack” space for the Gosub/Return pointers. Problems arise if you are executing a subroutine and decide to abnormal- ly jump out of the subroutine with a Goto command. This will leave a Gosub/Return pointer on the stack throughout the rest of your program, and the computer will always think it is one level deeper into nested subroutines than you actually want it to be. Applesoft provides a way out of this with the POP command. This single word command should be used just before the Goto is executed. An example of how this might be used is shown in Example 1. POP removes the last pointer address from the Gosub/Return stack just as though a Return command had been executed. Circle 43 on Reader Service card. APPLE-COMPATIBLE MINIFLOPPY SYSTEMS for your APPLE Il Disk Drive* selecable 13 oF 16 secror boot DISK DRIVE CABLE. Free With Purchase of Drive. There isa 15 DAY FREE TRIAL ON DRIVES Warranty 120 days Add $400 per dive for shipping in Cont. 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We do nor charge your ced card until the day we shia CALL TOLL FREE (800) 824-7888, Operator 24 Colfomnia chal (800) 852-7777, Operatex 24, Aiasko & Kowal diol (B00) 824-7919, *Operater 24 TOLL FREE LINES FOR ORDERS ONLY, Technical informanon & senace call (214) 397-4346 ep a, ae, AERUL vine P.O. Box 24829 Dallas, TX 75224 30 Gider April 1983 pens up toallow you quick Locked with the the APPLE-CENTER Apple and 2 disk drives. The key Apple and your monitor. Both outlets are protected from dam- aging voltage surges with RKS Industries’ SURGE SENTRY. We've even built in a filtered coolin Model 10 comes without electronics and is compatible with side mounted fans (applexcenter ) Cail or write for additional inform: switches power to your Ba Doss ES 1224 Mariposa, San Francisco, CA 94107 (415) 861-2223 Apple is a registered trade mark of Apple Computer Inc. The Applesoft Adviser— 1150 subroutine begins here 1280 IF R% > $% THEN POP: GOTO 350 1340 RETURN Example 1. POP command illustrated. For program clarity, however, such abnormal jumps out of subroutines should be used very sparingly. Structuring Programs Using Subroutines There are two main reasons for us- ing subroutines. The first is to avoid having to repeat the same block of code several times within a single program. A specific subroutine can be called up several times by the main program each time it is needed. The Return command. will always send the program back to the ap- propriate spot in the main program from which sequential execution again begins. Subroutines used for this purpose are best placed near the beginning of a program (low line numbers). This improves program ef- ficiency, since Basic begins looking for the Gosub line number at the first line of the program, and continues searching through the line numbers until it finds the one called for. I generally begin my main pro- gram routines at line 1000, reserving the first lines of the program for Remarks and a GOTO 1000 com- mand. This leaves plenty of room for these frequently used subroutines. A second use for subroutines is often overlooked by the Basic pro- grammer, probably because it is too easy to simply sit down and begin writing code. Programming ought to begin with a carefully thought out design that depicts each of the pro- gram’s main functions. Then each of these functions should be further defined in terms of sub-functions. Each sub-function should be dealt with in the same way, until the entire program is displayed as a clearly defined sequential execution of fairly simple functions. Only then should the first line of code be written. Each simple func- tion defined at the end of the pro- gram analysis stage may be written as a unique subroutine. The main pro- gram then becomes a series of Gosub commands. If copious use of Remark statements is made, the program be- comes almost self-documenting. The flow of logic is easily read from the se- quence of subroutines. I find it useful to use the line number immediately preceding the first line in a subrou- tine for an appropriate Remark state- ment that identifies the subroutine that follows. For example, if my subroutine starts at line 800, then line 799 will have the identifying Remark Circle 161 on Reader Service card. se @ Hewlett-Packard Call for Complete Computer Case Catalog. Credit Card Customers Call Toll Free Call (800) 847-4176 For Protection! _| Aluminum @ Apple Shipping Case Bese Removable Cover Carrying Case ram | @ Atari $215.50" $142.50* Ge Beale | @ AVL Apple II cases @ Sanyo | holding 2 ! @ Bell & disk drives Pains e TRS-80 Howell enol Shipping Case ee | @ Centronics $216.50 o~ | é - @ Commodore ABS Storage Zenith & Carrying Case @ Epson R sbleG @ Texas emovable Cover $69.50" Instruments e IBM “UPS Shipping Included. @ NEC ea TaN Fiberbilt Ikelheimer-Ernst, Inc. 601 West 26th Street New York, New York 10001-1199 (212) 675-5820 (NY.C. area) April 1983 @ider 31 UNTIL A=BDO... 100 IF A = B THEN 190 110 program block to be repeated The Applesoft Adviser 180 GOTO 100 190 program continues from here Example 2, Until/Do shortcut. statement. In this way, if I find that I must remove Remarks in order to make more room for my program, I can find them easily and remove them without fear of deleting a line number referenced by a Goto or Gosub command. There are several advantages to designing a program in this fashion besides the ease with which it can be read. Once you have become used to writing programs using structured techniques such as this, you will find that the time spent writing a given program will be considerably short- ened. You will identify subroutines you have used before that can be simply copied into your new program with little or no change. You will find that new subroutines can be tested out by themselves to verify that they are written correctly, without having: to run through the entire program to test a single function. You will find that later, when you come back to the program to make modifications in its operation, those changes will be much easier to make with less chance of interfering with another part of your program. Conditional Short-Cuts Basic programs in which the following sequence of instructions (or its equivalent) is used are all too common. IF A> 15 THEN GOTO 820 IF A<= 15 THEN GOTO 750 Based on the previous discussion, it is obvious that the second relational comparison is not needed. It merely slows the execution of the program. The instruction GOTO 750 could be used in its place, with the same results. Flags are often employed in pro- grams to be used in conditional ex- pressions. For example, a certain part of a program might be used for both data entry and for editing. Sup- pose the common instruction block is part of the main program for data entry, and a flag, say F2%, is zero during data entry. Now suppose the same instruction block is used as a subroutine for editing, with F2% set to 1. The following line could be used to return from the instruction block for the editing routine: IF F2% THEN RETURN F2%, by itself, is taken as a logical relationship and is evaluated as “true” or “false” based on its value. So long as its value is not zero, it will be evaluated as “true.” Two programming structures not supported by Applesoft are the Un- til/Do and the Repeat/Until com- Circle 97 on Reader Service card. gee Magic, MACHINE LANGUAGE SPEED WHERE IT COUNTS... IN YOUR PROGRAM! Some routines on this disk are: Binary file info Delete array Disassemble memory st time, Amper-Magic makes it easy for people who don’t know to use its power! Now you can attach slick, finished machine language routines to your Applesoft programs in seconds! And interface them by name, not by address! You simply give each routine a name of your choice, perform the append pro- cedure once at about 15 seconds per routine, and the machine language becomes a permanent part of your BASIC program. (Of course, you can remove it if you want to.) Up to 255 relocatable machine language routines can be attached to a BASIC program and then called by name. We supply some 20 routines on this disk. More can be entered from magazines. And more library disks are in the works. These routines and more can be attached and accessed e: For example, to allow the typing of commas and colons in a response (not normally allowed In Applesoft), you just attach the Input Anything routine and put this line in your program: xxx PRINT “PLEASE ENTER THE DATE.”; : & INPUT,DATES Dump variables Find substring Get 2-byte values Gosub to variable Goto to variable Hex memory dump Input anything Move memory Multiple poke decimal Multiple poke hex Print wio word break Restore special data Speed up Applesoft Speed restore Store 2-byte values Swap variables Anthro - Digital Software P.O. Box 1385 Pittsfield, MA 01202 The People - Computers Connection &-MAGIC makes it Easy to be Fast & Flexible! PRICE: $75 & Magic and Amper-Magic are trademarks of Anthro-Digital, Inc. Applesott is a trademark of Apple Computer, Inc. 413-448-8278 32 @ider April 1983 REPEAT...UNTIL A=B 100 beginning of program block to be repeated 180 IF A<>B THEN 100 190 program continues from here Example 3. Repeat/Until command. The Applesoft Adviser— mands. These two commands are common in structured languages such as Pascal. They identify a block of instructions that are to be carried out repeatedly until a specific condi- tion is met. The main difference be- tween the two is that the condition is tested before the instruction block is carried out with the Until/Do struc- ture, while the condition is tested after the instruction block with the Repeat/Until command. The temp- tation in Basic is to set up a For/Next loop and write a conditional test within the loop that will cause the computer to jump out of the loop when the condition is met. This in- volves another Goto jump, and pre- sents other hazards which I brought out in my March article. In Basic, the Until/Do command can be accomplished by stating the condition before the loop using an If/Then as in Example 2. The Repeat/Until is carried out by reversing the conditional relationship and using the If/Then after the block of instructions to be repeated if the condition is not met, as in Example 3. Although both of these constructions in Basic use the Goto command, the jumps are to points immediately con- tained by the looping structure and present no problems in obscuring the goal of the program. In fact, if the program block that is to be repeated is itself a complete subroutine, the Until/Do and Re- peat/Until constructions become “one-liners”: 100 ‘IF A<>B THEN GOSUB 1200: GOTO 100 and: 100 GOSUB 1200: IF A<>B THEN 100 This approach really tightens up the program logic! Take note of the reversal in the conditional expression for the program line that mimics the Until/Do command. Emulating the If/Then/Else In Applesoft Relational and logical expressions are evaluated to +1 if true, and to0 if false. Knowing this makes it possi- ble to set up the equivalent of an If/Then/Else statement in Applesoft, and at the same time to structure the program so that the leapfrog effect mentioned earlier is entirely avoided. Many advocates of structured pro- gramming decry the use of the Goto command, maintaining that the Circle 182 on Reader Service card. SAVE MONEY! Increase your computer's productivity The INTERSTELLAR DRIVE is a high performance data storage subsystem with independent power supply, battery backup, and error detection. It has 256KB to 1 Megabyte of solid state memory integrated a perform with your operating system. -INTER ELLAR DRIVE: Me Save valuable time! ormance than floppy disks ’ and Winchester drives PION’S INTERSTELLAR DRIVE is designed for use with a family of interfaces and software packages. Currently avail- able are interfaces for IBM, $100, TRS80, Apple, SS50, and most Z80 uP, and software for most popular operating systems. e Additional interfaces are continually being developed for the most popular computers. Basic Price for 256KB unit inctudes interface and software] $ 1095,, Plus tax (where applicable) and shipping ‘Visa and Master Card accepted. PION , inc. 101R Walnut St., Watertown, MA02172 ‘TRS80 trademark of Tandy Corp. Apple trademark of Apple Computers Interstellar Drive trademark of PION, Inc. 5 to 50 times faster Tel.(617)923-8009 yy, April 1983 @ider 33 CASE expression OF 1: command list 1; 2: command list 2; The Applesoft Adviser- 8: command list § END; Example 4. Case/Of command. main program logic should flow in an uninterrupted sequence from start to finish with no sudden jumps initiated by a GOTO #####. The If/Then/Else construction, used with subroutines, can eliminate a lot of these Gotos. The key here is to use the ON...GOSUB ####, ##4 com- mand. When this command is en- countered, the computer evaluates the expression (which may be a single variable, an arithmetic expression, or a relational or logical expression). If the expression evaluates to 1, then the first set of line numbers after the Gosub is used. If it evaluates to 2, the second set is used. In fact, any number of line numbers could be listed in sequence following the Gosub command to correspond to any small positive integer to which the expression could evaluate. If the ‘expression evaluates to the number 8, the computer would look for the eighth line number in the list and ex- ecute a Gosub to that subroutine. If the expression evaluates to some number too large to match with a line number in the list, the computer ignores the statement and continues on to the next command. (Incidental- ly, the same command can be used with Goto instead of Gosub, but this defeats our efforts at structured pro- gramming, right?) Now suppose that we set up two subroutines for a particular condi- tional test within our program. The first, beginning at line 1500, will con- tain the instruction set to be followed if our conditional relationship proves to be true, while the second, begin- ning at line 1600, deals with the false relationship. If the relationship being tested is equality between the two variables, AB and AC, then the following statement could be used: 80 ON (AB = AC) + 1 GOSUB 1600, 1500 In line 80, the relationship between AB and AC is tested. If the two are equal, the result is + 1, to which 1 is added, making the entire relation- ship equal to 2. Thus GOSUB 1500 will be executed. On the other hand, if AB and AC are not equal, then the result of the relationship is 0. When 1 is added to this result, the GOSUB 1600 command is executed. This is equivalent to: 80 IF AB = AC THEN GOSUB 1500 ELSE GOSUB 1600 Of course, Applesoft does not support the Else statement, so the only way to handle this situation is with the ON...GOSUB command. Notice that the main program logic flows smoothly from line 80 to line 90 with no leapfrogging or ugly jumps. Another construction found in Pascal and structured languages is the Case/Of command. This com- mand is followed by a list of instruc- tions, only one of which is to be selected based on evaluation of the expression in the Case command. This command looks something like Example 4. If you are ahead of me, you may recognize the similarity between this and the ON. ..GOSUB construction that we have already dealt with. In the Case/Of construction, if the ex- pression evaluates to 1, then the first command list is carried out; if it evaluates to 2, the second command list is used; and so on. In Basic, if each command list is made into a separate subroutine, then ON. . .GOSUB car- ties out the same function. The relationship does not stop here, however. The Case/Of com- mand can also use letters or complete words to specify which of the com- mand lists to carry out. Basic also has this capability, if we are ingenious enough to construct the proper rela- tional expressions to use for our ON. ..GOSUB expression. Consider the Case/Of expression in Example 5, which calculates the volume of various solids: The Pascal program will evaluate the string CASE SHAPE OF CUBE: VOL=S*S"S; BOX: VOL=L*W*H; SPHERE: VOL =(4/3)*PI*R*R‘R END; Example 5. Case/Of expression. variable named SHAPE, and carry out the desired calculation if SHAPE is equal to “cube,” “box,” or “sphere.” In Basic, if SH$ represents the shape of the object, then we can formulate relational expressions to use in an ON. ..GOSUB statement. For example, the expression (SH$ =“CUBE”) will evaluate to +1 if true and to 0 if false. If we multiply this expression by some number, then the result will be that number when the expression is true, and zero when itis false. The Basic construction that carries out the Case/Of example shown above then becomes: ON (SHS=“CUBE”}*1 + (SH$=“BOX”)+2 + (SH$ =“SPHERE”)*3 GOSUB 1100, 1150, 1200 So if SH$ is “SPHERE,” the entire ex- pression becomes 0+0+3=3 and the third subroutine, at line 1200, will be the one selected. Conclusion Although no specific applications programs were given in this article, I hope that you will find numerous ap- plications for some of the concepts that I have described. Take a look at some of the programs you have writ- ten already. Count the number of Goto jumps within the program. Then see if you can redesign the pro- gram with an emphasis on individual functions. Write subroutines for these functions and then put the pro- gram back together using these modules and eliminating as many of the Gotos as you can. Not only can this be an interesting exercise, but it can help you begin to think in terms of structured programming. You may never be the same again! In my next article, I will modularize random access disk file routines and suggest how it may be possible to use the disk for random access data storage with very little confusion or headache. If you have been avoiding random access files because sequential files were more familiar, then the time has come to graduate to the faster, more versatile world of random access. You will be surprised at how easy it can be! ll 34 Cider April 1983 “YOU DON’T HAVE TO GET HIT OVER THE HEAD TO REALIZE HOW QUICKLY APPLE TECHNOLOGY IS CHANGING.” “It used to be that those one-size-fits- all computer magazines were fine for learning more about computing. In fact, they were about all one could find. And it was a treasured issue in- deed that contained more than one ar- ticle about your particular system. The ‘gravity of this situation was beginning to dawn when suddenly it struck me...and I made the greatest discovery of my career, inCider. inCider is a monthly magazine devoted exclusively to the Apple* com- puter. It’s published by the same seasoned editorial staff that produces 80 Micro. Each issue of inCider con- tains more Apple-specific information than any other magazine, including: *programs earticles applications *new product announcements ereviews tutorials eutilities inCider promises to revolutionize the world of Apple computers for only- $24.97. You'll receive 12 monthly issues of inCider loaded with money-saving ads and advice, each issue saving you several times your initial investment. Enclose payment or use your credit card and receive a 13th issue FREE! It doesn’t take a genius to know a great deal when he sees one.” Send in the attached order form, the coupon below, or call toll free 1-800-258-5473 inCider Subscription Department PO Box 911, Farmingdale, NY 11737 ‘Apple is a trademark of Apple Computer ine. oe: I want a subscription to inCider for one year at $24.97. j l T understand that with payment enclosed or | credit card order I will receive a 13th issue FREE. | Cctock endowed OMC OVISA OAE CBill me | Cart | Exp. date. ] signature. Interbank \ Name © j Adéres 3 [cy State_ —Zip. — I Fearag his rel-sack ge onl US Foreign surface $44.97, 1 year only, US funds drawn on US April 1983 @ider 35 The Assembly Advantage by Randall Hyde Ox the beginner masters his Apple computer and develops a strong command of the Basic lan- guage, thoughts immediately turn to optimization. There’s probably not a single program written that couldn't benefit from extra speed or addition- al features. So the beginner learns Basic tricks, like removing Rems, moving subroutines to the beginning of the program, and declaring often- used variables early in the program. Ultimately, however, jerry-rigging fails to achieve the needed improve- ment and the programmer is forced to contemplate use of a faster lan- guage. While faster high-level lan- guages, like Pascal and Forth, are available for the Apple II, these lan- guages can’t come close to 6502 as- sembly language. For the program- mer writing time-critical code (like a hi-res arcade game) using 6502 ma- chine code is an absolute necessity. However, 6502 assembly lan- guage, the gateway to 6502 machine code, is difficult to learn. To ease the burden I have created a set of subrou- tines, collectively called Speed/Asm, to help minimize the effort. This se- ries of articles will describe how you can easily create your own machine language programs using the Speed/ Asm package. Speed/Asm, like its companion, the LISA interactive assembler, is es- pecially designed for the beginner at 6502 assembly language program- ming. I developed these packages as tools for use in the assembly language classes I teach in southern California. Tve discovered that students who learn 6502 assembly language using the Speed/Asm package achieve com- petence much faster than those who learn using traditional methods of in- struction. Speed/Asm is a collection of sub- Trying Out the Tools— Some Basics routines you call from your program to perform certain tasks. In particu- lar, the Speed/Asm subroutines emu- late many of the statements found in Basic and Pascal. For example, the Basic program 10 FORI=1 TO 100 20 PRINT I; 30 NEXT I is translated into Speed/Asm as JSR FOR ADR 1,1,100 JSR PRTINT ADRI JSR NEXT Persons using a macro assembler, like LISA version 3.0, could even code this as .FORI,1,100 -PRTINT I .NEXT As you can see, Speed/Asm looks quite a bit like Basic. But keep in mind that Speed/Asm is assembly language so you get a considerable performance boost compared to Basic. Getting Started Probably the best place to start is with the disk that comes in the Speed/Asm package. A quick cata- log of the disk reveals that about 11 programs are included. The file Speed/Asm is the boot program that does the cataloging. RELSA and RELFP are two pro- grams used to generate a Speed/Asm program. Speed/Asm is relocatable to any page boundary; RELSA and RELFP are the programs that create an absolute version of the Speed/ Asm program for actual use. RELFP generates a full Speed/Asm package, including the floating point opera- tions. RELSA generates a copy of Speed/Asm without the floating point subroutines, hence it is much shorter. SAFP.78, the next program on the disk, is a copy of Speed/Asm that has been located to address $7800. This file is provided for the convenience of those who want to write programs as quickly as possible without having to learn how to use the RELSA or RELFP program first. I will use SAFP.78 in all the examples I pre- sent, although only one line in your program will need to be changed if you wish to use Speed/Asm located at some other address. The SA.EQUATES file contains equates for all the Speed/Asm sub- routines. The file on this disk is pro- vided in a LISA2.5 compatible for- mat (which can also be read in by LISA version 3.0). For those who are using an assembler other than the LISA interactive assembler, the SA.EQUATES file is reproduced in the program listing. Incidentally, if you’re a beginner and in the process of choosing an as- sembler, I would highly recommend a look at LISA. It is an interactive as- sembler that makes learning assem- bly language much easier. Unlike other assemblers, LISA catches errors on input, much like Basic. I’m going to make the assumption, in this column, that you’re using the LISA assembler. Attempting to de- scribe every LISA feature to users of other assemblers would be too great a distraction. Attempting to write the code in a general fashion would make the programs overly large and confusing. The remaining six programs pro- vided on the Speed/Asm disk are test Address correspondence to Randall Hyde, La- zer Microsystems, 1791 Capital, Corona, CA 91720. 36 Gider April 1983 The Assembly Advantage $0000 — ["appLe sySTEM VARIABLES $0400 —*|"aprue ExT ‘SCREEN MEMORY programs that were used to help vali- date the Speed/Asm package. You may want to look at these files to get an idea of how Speed/Asm programs are written. Preparing for Your First Program Before we can jump in and run our first program there are several deci- sions that must be made. To begin with, we must decide where the pro- gram will run. Unlike Basic, which uses the same data in memory for the source code and run-time code, as- sembly language programs must be converted from a source (human- readable) format to an object code (computer-readable) format. This conversion is accomplished by an as- sembler like LISA. Once the source file is converted to object code you can run the program by executing the object code, Most assemblers on the market (in- cluding LISA) operate in a co-resi- dent mode. This means that the source text file and object code both reside in memory during the assem- bly of the program. Since both files are maintained in RAM at the same time, care must be taken to ensure that the source and run-time object code do not disturb one another. In Basic, memory was allocated auto- matically for you. While using 6502 assembly language, the memory management chore is left up to the programmer. So extra care must be taken when creating programs, By referring to Figure 1 you can get an idea of what the Apple’s mem- ory space looks like while using LISA. In particular, locations $800 through $17FF are reserved for holding your object code, and locations $1800 and up are reserved for the source file. Four kilobytes of RAM should prove to be sufficient for most programs. Advanced programmers who require more RAM should consult the LISA documentation to find out how to ad- just the default textfile/object code size settings. Whenever you assemble a pro- gram, LISA automatically begins assembling and storing the code at lo- cation $800, Unless you want to as- semble the code at some other loca- Sovc0 —+ |r