Re: Now the fun begins...

[dempson@actrix.gen.nz (David Empson)]

Roger Johnstone <rojaws@es.co.nz> wrote:

> ----------
> In article <wuPa4.286$Wd4.35146567@alpha.sky.net>, jmholmes@swbell.net
> (John) wrote:
> 
> >I've seen several SCSI Hard Drives in the 200-400 meg range on ebay that all
> >say that they have apple ROMS.  I do remember from my Macintosh days that
> >those were the ones to get since you couldn't use the Apple HD Format Utility
> >(or something to that effect) if you didn't have the Apple ROM.  
> >
> >Does this same limitation apply to the //GS systems or can you just go
> >get any old SCSI hard drive and expect it to work correctly (assuming the
> >drive is functional).  I do have a couple of extra external SCSI drive
> >boxes laying around from my old Mac Plus, though the drives in them are
> >dead.
> 
> Good news, as far as I've seen you can use any SCSI hard drive you like on a
> IIgs.

This isn't entirely true.  It depends on which SCSI card you have.

The Apple cards will work with nearly any single-ended SCSI hard drive.

The RamFast won't work with some recent hard drive models, since it
doesn't implement the SCSI arbitration phase, which is required by
recent drives.  Known models that have problems include the Quantum
Fireball series (I don't know which particular variant, but the drive
was about 500 MB in size) and some IBM models.

No Apple II SCSI card will work with "differential" SCSI drives, but LVD
("low voltage differential") may be OK.

> In fact you can use a IIgs and the Advanced Disk Utilities to format a
> non-Apple drive with HFS and a generic Mac driver and use it on a Mac! When
> a Mac formats a drive it puts a driver on it in a special invisible
> partition. The formatting utilities Apple supplies with the Mac check the
> drive model name stored in ROM, if it matches one Apple has ever SOLD (ok,
> and tested) they let you format it. I don't think they really have a custom
> ROM.

They do indeed have a custom ROM, or at least they used to.  The ROM was
patched so that the drive manufacturer name was changed to read "APPLE"
(instead of "QUANTUM", "IBM" or whatever).

These patched ROMs were used for many years.  For example, the Quantum
40MB drive in my SE/30 has this patched ROM.  I haven't investigated the
1.2GB drive from my 7600.

If I remember correct, the "Apple HDSC Setup" utility (on the Mac) only
supports Apple-patched drives.  The "Drive Setup" utility (also on the
Mac) is more flexible.  It works with Apple-patched drives as well as
known compatible drives from a variety of manufacturers.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand