Daniels Lisas Alternative Operating System Computer Design

SPECIAL REPORT ON MICROSYSTEMS SOFTWARE LISA'S ALTERNATIVE OPERATING SYSTEM The rigid command language syntax and mode based structures of conventional operating systems may be a thing of the past. by Bruce Daniels Lisa, an advanced personal computer system, radically changes the way people interact with a computer. In traditional microcomputer operating systems, interaction occurs strictly via a special command language. With Lisa, however, the use of a very intuitive and consistent electronic desktop model allows interaction through pointing and graphics. Although traditional operating systems provide a raw capability for general purpose computing, they are excessively complex, arcane, and difficult to use. Thus, they do not meet the needs of nonexpert computer users. Nor do these systems provide all the required functionality since they do not support rapid switching between simultaneous activities. In addition, the convenient examination and transfer of data between these interdependent activities are not supported. Furthermore, existing systems cannot be easily modified . The Apple's Local Integrated Software Architecture (Lisa) takes a revolutionary approach to Bruce Daniels is a consulting engineer at Apple Computer, 20525 Mariani Ave, MS 2P, Cupertino, CA 95014, where he is responsible for software architecture, integration, performance, and reliability for the Lisa Div. He has BS and MS degrees in computer science from the Massachusetts Institute of Technology. . . ..... .. ......... ........... ........ ·.·.·.·.·.·.·.·.· . ................................... . . ..... .. D c::[> El] operating system software, resulting in an integrated system that is an order of magnitude easier to use. This new approach, not constrained by the traditional structures of existing operating systems, is concerned almost exclusively with providing features that make the computer easier or more convenient for the nonexpert user. With today's technology, the difficulty of providing such a feature is minimal. Five concepts are implicit in Lisa's operating system. First, Lisa is a personal computer. As COMPUTER DESIGN/August 1983 15 9 EDIT FILE/PRINT TYPE STYLE ARRANGEMENT LINES SHADES UNDO ARCHITECTURE ~ CALCULATOR ,D/ ~ CUT COPY PASTE CLEAR I /~ .) 0 " ~ WASTEBASKET ! " ". EJ @ MY DISK CLIPBOARD Jo]! [;!] 1 D D D D STRUCTURE OS DESKTOP MANAGER WASTE· BASKET What is the Lisa? Lisa represents over 200 person years and $50 million of development effort. Its intellectual inspiration came from the Smalltalk language and operating system developed at the Xerox Palo Alto Research Center. This system's pioneering use of graphics and a mouse to present the fundamental concepts of overlapping pieces of paper on an electronic desktop marked a departure in computer operating software. Taking the Smalltalk concepts, Apple spent three years refining them, adding innovations, and reducing costs. Hardware is based on the MC68000 micr…