Re: CD-SC problem

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

In article <8B311EA.0221001005.uuout@digitec.co.za>,
STEPHEN SHAW <stephen.shaw@digitec.co.za> wrote:
> 
> So far as I know the CD will only work with a IIgs. Sequential wrote 
> some software to allow a IIgs to read Mac and IBM format CDs (I think 
> the protocol is called High Sierra after the originators). A //e 
> hasn't got the horsepower (being 8 bit) to use the CD-ROM.

I haven't used a CDSC on a IIe for a long time (and then only
briefly), but it does work.

If you have the original Apple SCSI card, the main requirement is that
you have the revision C ROM.  Earlier ROMs do not support a CD-ROM at
all.  Revision C supports the Apple CDSC (the original Apple CD-ROM
drive).  It might also work with the CDSC+ and CD-150, but some
features may not be available.  Audio support will be missing for the
CD-300 and later models, but they should still work for accessing data
CDs.

An Apple High-Speed SCSI card is similar - audio will work fine with a
CDSC, CDSC+ or CD-150, but not with later models.

Regarding booting: you can only boot from a CDSC on a IIe (or IIgs) if
the CD has a ProDOS partition containing the usual ProDOS boot blocks
and PRODOS file.  This narrows your options a lot: it almost certainly
has to be an Apple II-specific CD-ROM.

On a IIe, I don't know of any software to allow access to other
file systems on a CD-ROM.  A2FX and HFSLink _might_ work with an
HFS-format CD, but I've only ever used them with floppies.  Most
portable CDs use ISO-9660 (or High Sierra), and I don't know of any
8-bit software to read them.


In an earlier article on this thread (which I haven't seen), John Le
Febvre <john@klatch.demon.co.uk> wrote:

> JL> I removed the HDD from the chain, plugged the SCSI system cable 
> JL> into the CDSC and placed a terminator on the other socket of the 
> JL> CDSC, as stated in the manual.

Sounds right, as long as the hard drive was not connected.  If both
drives are connected, you need two terminators: one between the
computer and first drive, one after the second drive.  (This is
because the original Apple SCSI card has no built-in termination
resistors.)

I see from later in your message that your hard drive has internal
termination, so this should cover it in conjunction with a terminator
after the CD-ROM.

> JL> I powered the CDSC, inserted the boot CD, waited a few seconds 
> JL> for it to register and powered the //e, which attempted to boot 
> JL> from the Disk II drive in slot 6.

An Enhanced IIe should be able to boot from the SCSI card (an
unenhanced IIe would ignore it).  This sounds like the SCSI card
didn't recognise the CD-ROM drive or disk.

> JL> Typing PR#7 from BASIC.SYSTEM results in DEVICE NOT CONNECTED. 
> 
> JL> Is this a TrmPwr problem, or does the CD-SC look busted?

Could be either.  It is unlikely that the CD-ROM will be supplying
termination power, so things might not work properly unless your hard
drive is connected, and it is supplying power.  You could try removing
one of the terminators - under-terminating the bus (or having no
termination) might get around problems with lack of termination power,
but will introduce signal reflections that might make things worse.

Another possibility: are you absolutely certain your SCSI card has the
revision C ROM (341-0437-A)?  If it is 341-0112-A or 341-0112-B, then
you have revision A or B, and the ROM needs to be upgraded to support
a CD-ROM drive.

Also check the SCSI IDs involved.  Was the CDSC supplied in its
original Apple external case, or was it a mechanism added to another
case?  In the latter situation, the SCSI ID selector might not be
connected properly to the drive, so the ID setting may be incorrect.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand