Re: Apple CD 300e Plus

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

Steven Nelson <steven-nelson@uiowa.edu> wrote:

> On Apr 24, 9:06 am, "Polymorph" <polymo...@a2central.com.remove-11e5-
> this> wrote:
> >   To: Polymorph
> >
> >
> >
> >
> >
> > Polymorph wrote:
> > > On Apr 22, 7:44 am, dog_...@macgui.com (D Finnigan) wrote:
> > >> amotyka wrote:
> >
> > >>> I've read on the faqs that Sequential Systems sold a SCSI-2 driver for
> > >>> the apple card, which I'm hopeful would make everything run smoother.
> > >>> However I have spent the day trawling the internet for such a driver
> > >>> with no luck.
> > >> Try this:http://macgui.com/downloads/?file_id=12199
> >
> > > Excellent! I asked about this same driver a couple of years ago and
> > > got nowhere fast. I even mentioned it to Jawaid Bazyar (the author of
> > > the driver) last year when he was selling all of his Apple IIgs stuff,
> > > and I never heard anything more. I'll try this out tonight.  :-)
> >
> > OK, I tried the posted driver but I'm pretty sure its meant for the
> > RAMFast, not the Apple HS SCSI.  :-(
> >
> > You can pretty much guess that from RAMFasts naming convention of
> > RF.SCSI2. At any rate, it isn't the driver I was after unfortunately
> > (and it doesn't work with the Apple HS SCSI). But thanks anyhow.
> >
> > If anyone knows where to get the Sequential Systems SCSI-2 driver for
> > the HS SCSI, please let me know.
> 
> If you have access to old csa2 posts (I use google groups) look for
> the the thread "Can IIGS use this CD-ROM drive?? - Drivers"
> from early 1999.  I had no luck trying to buy the drivers from
> Sequential Systems back then.  (I was ISCA Librarian).  At the time I
> was pretty sure that David Empson had the scsi2 driver, but I am sure
> he would have spoken up if he had it, so that was another false lead.

I found a relevant posting of mine from 2002. At the time my
recollection was that a SCSI-2 driver had been announced but never
released. It was going to be a media control driver (for controlling
audio CD playback), nothing to do with data access. I haven't been
actively involved with the Apple II community since well before then so
I don't know if that impression was correct or anything changed since.


Apple's early SCSI CD-ROM drives used a proprietary audio command set,
but switched to the newly defined standard command set somewhere around
the CD-300e (or it might have been the CD-150). The drivers for the IIgs
from Apple never caught up.

Data access was well defined as far back as the original CD-SC, so later
drives which supported SCSI-2 should still work for data access with the
original IIgs and/or SCSI card firmware drivers.

In GS/OS there is no practical difference between Apple's original and
high-speed SCSI cards as far as device support is concerned. The card's
firmware is not involved. All drivers are supplied by GS/OS and access
the hardware directly.

The only remaining differences are speed (lack of DMA with the original
card) and termination (high-speed card has termination built in for the
"near" end of the SCSI bus, but original card doesn't, neither card
supplies termination power unless modified).

The differences between the original and high-speed cards are more
signficant for 8-bit software, e.g. the original card (with rev C
firmware) supports a maximum of 7 volumes (drives or partitions) while
the high-speed card supports more than 100 via the SmartPort API, and
the original card's firmware doesn't understand the concept of a
removable hard drive, so things like Zip drives aren't handled properly
if ejected and a new disk is inserted with a different partition table.

-- 
David Empson
dempson@actrix.gen.nz