Thread
Macintosh Hard Disk 20
on iisi, go to start up disk, chose hd20 and reboot, then see if it boots?
The HD20 INIT is both the driver and the HFS File system driver. If you want "built in" support on a 128k and 512k, just swap in the Macintosh Plus ROMs. As an added bonus, you get 800k drive support.
yeah but then the purists get their panties in a bunch. 
the floppy emu should take care for the init… then eject… then emulate a HD20, with a 1gig image!
now that sounds fantastic!
the floppy emu should take care for the init… then eject… then emulate a HD20, with a 1gig image!
now that sounds fantastic!
I never found much "official" info on the topic, but the HD20 does not work at all on the 128k, INIT or no. There just isn't enough memory available.
edit: On further reflection I suppose it is at least theoretically possible that a Plus ROM swap would solve that problem.
edit: On further reflection I suppose it is at least theoretically possible that a Plus ROM swap would solve that problem.
It may have been my particular board, but on one 128k board I tried Plus ROMs and it would not work. Checkerboard screen. ROMs were tested just fine. Don't quote me though, I have not tried other ROMs yet. It is something I want to do when I have time.
I'v tried plus roms in a 128k,
with different boards in differen instances.. and it always worked… its just STRANGE having a 128Ke!!!
lol
the INIT is 28k.
http://www.mac512.com/macwebpages/hd20.htm
ya i dont get it… this website says this:
with different boards in differen instances.. and it always worked… its just STRANGE having a 128Ke!!!
lol
the INIT is 28k.
http://www.mac512.com/macwebpages/hd20.htm
ya i dont get it… this website says this:
but then it says this:
So yeah i don't get it. I guess all there is to do test it first hand.
Done! The IIsi attempts to boot off the HD20. Doesn't get very far, because the HD20 has System 6.0 which doesn't support the IIsi. But it reads, says Welcome to Macintosh, then a polite suggestion to get a newer System and be sure to install support for the IIsi.
Under OS 7.6 I copied some software from the HD20 to the internal disk, and the application runs fine -- so I can be reasonably sure that data copied in that direction is OK. However, I've seen some references to "partial" HD20 support on newer Macs only meant to copy data from, not to, the HD20. I don't really feel like borking a filesystem tonight...
Aside from me feeling a bit risky since HD20s don't grow on trees, the IIsi seems perfectly happy exchanging bits with the HD20.
alright lets add the IIsi to the list!
next we should try a SE/30 with a dougg3 rom.
IIcx
SE FDHD
next we should try a SE/30 with a dougg3 rom.
IIcx
SE FDHD
SE FDHD work without init. Although accelerator is in it.
! have great news… the se/30 boots from the HD20, with Dougg3's ROM simm installed!
lol i have great news IIcx boots the HD20 with dougg3's rom simm installed.
my hunch is the IIx and IIfx would also boot hd20 with dougg3's rom simm!
obviously it would have to be hooked to the internal floppy connector… no big deal… i have a 2 foot floppy cable hanging out of my MacII for the Floppy Emu already.
as soon as i get my package from olepigeon, I'm going to try and solder a rom simm slot onto the Mac II.. and try dougg3's rom.. i am almost positive it will work.
now all we need is to get a BMOW Floppy Emu … to Emu a HD20 !!
obviously it would have to be hooked to the internal floppy connector… no big deal… i have a 2 foot floppy cable hanging out of my MacII for the Floppy Emu already.
as soon as i get my package from olepigeon, I'm going to try and solder a rom simm slot onto the Mac II.. and try dougg3's rom.. i am almost positive it will work.
now all we need is to get a BMOW Floppy Emu … to Emu a HD20 !!
Using the HD20 hard drive… I would say its speed is similar to Booting your computer up and running it with an IOMEGA SCSI Zip 100.
I don't find it to be abnormally slow at all… that IWM is working its magic!!!!!
maybe even black magic!
I don't find it to be abnormally slow at all… that IWM is working its magic!!!!!
maybe even black magic!
It transfers data at effectively 7/8ths * 500kb/s, IE, around 55K/sec. In *theory* the SCSI version of the original ZIP 100 should be capable of bursting around a megabyte a second but the SCSI hardware/driver implementation in early Macs like the Plus is so horrible that the 55K/s from the HD20 is, well, almost in the same ballpark. (A Plus falling downhill with a tailwind can eek around 200-250K/s with a sufficiently fast drive.) If you're running System 6-era programs they're going to be small enough that the speed is going to be "adequate".Using the HD20 hard drive… I would say its speed is similar to Booting your computer up and running it with an IOMEGA SCSI Zip 100.I don't find it to be abnormally slow at all… that IWM is working its magic!!!!!
maybe even black magic!
For any Mac that *does* have a SCSI port it makes a lot more sense to fit a SCSI->Flash adapter for "production" use; it'll be faster and more likely to be bootable. That said, I'm totally rooting for BMoW or others to reverse engineer HD-20 emulation anyway for use with 512k(e)'s and friends, and there certainly might be some edge cases where it could be useful for data transfer purposes when attaching the device to a newer Mac.
If I had to hazard a guess as to when support for the HD-20 it was pulled completely it's the cutoff between models using the SWIM chip and the SWIM II. See this "what chips are in what Macs" list here. The HD-20 support is in the floppy driver and the SWIM II's drivers are completely different from the SWIM's. (Which means the HD-20 init definitely won't work to add it.) So if you really, really wanted to probe the edges of support you could try cooking up an adaptor from the internal floppy connector to external and hooking the HD-20 up to an LCIII or Quadra (later than the 700 and 900). Pretty sure you'll hit the wall there.