From: David Clunie (
Date: Fri Sep 25 1992 - 10:34:42 CDT

Some time ago I posted a question about using the Pioneer DRM600
CDROM Multichanger (6 disks) on a Sun sparcstation.

Thanks very much to the many people who posted advice, suggestions,
and sources of drives and software.

The most surprising discovery was the statement by many vendors that
a special driver was necessary - this was offered at the cost of about
$USD 400-500 over and above the drive itself !

Several individuals told me that they had just plugged the drive into
the SCSI port, recompiled the kernel to add another 5 logical units
to the SCSI target 6 (see below), and made sure that there were
devices for /dev/sr0 thru /dev/sr5 (already there in OS 4.1.2). The
only proviso being that the drive have a dipswitch on the back set to
512 byte sectors rather than 2048 and to have firmware revision 0804.

Sound too good to be true ? Well I tried it ... I pulled a Pioneer
drive off a PC at work, connected it to a Sparc, did as I had been
told and it works just fine. I tried ...

  - mounting and reading HSFS (ISO9660) disks - no problem
  - mounting and reading Sun UFS (4.2) disks - no problem
  - mixing both - the 2nd access hangs until the first type unmounted

Getting more ambitious I tried ...

  - booting mini-root off a CD - no problem (just as slow as usual)

  - installing SunOS 4.1.2 on an empty sparc from scratch - just fine

When multiple disks are mounted the regular sun sr driver just accesses
whatever logical unit it is asked to, and the Pioneer dutifully swaps

Now I ask you what extra functionality does the $500 driver from
Young Minds or Tracer Technologies or whoever offer above this
freebie from sun ? So far I have not been able to find out. Perhaps
earlier versions of the standard SunOS driver wasn't up to this,
perhaps the "extra" driver is more reliable or powerful or caches
better or something, but I am pretty happy without it. Furthermore,
not a single vendor I have talked to was aware, or would admit, that
an additional driver was not necessary !

Maybe someone who sells this driver can correct me, but if I had
already paid almost 50% extra for an unnecessary driver I would be
supremely pissed off ! I am very grateful to those who told me that
I could make do without ! (Hence this post to spread the word).

So what do you do to make it work ?

Add the following to your kernel:

disk sr0 at scsibus0 target 6 lun0 #CD-ROM drive
disk sr1 at scsibus0 target 6 lun1 #CD-ROM drive
disk sr2 at scsibus0 target 6 lun2 #CD-ROM drive
disk sr3 at scsibus0 target 6 lun3 #CD-ROM drive
disk sr4 at scsibus0 target 6 lun4 #CD-ROM drive
disk sr5 at scsibus0 target 6 lun5 #CD-ROM drive

Make the following devices in /dev:

mknod sr1 b XX 8
mknod sr2 b XX 16
mknod sr3 b XX 24
mknod sr4 b XX 32
mknod sr5 b XX 40

mknod rsr1 c YY 8
mknod rsr2 c YY 16
mknod rsr3 c YY 24
mknod rsr4 c YY 32
mknod rsr5 c YY 40

The devices may already be there ... mine were.

Where do you get a drive (plus or minus a driver !):

  Kintronics Computer Products
  914-347-2530 or 800-431-1658

  Young Minds inc
  (714) 335-1350

  Relax Technology

  Tracer Technologies
  800-872-2370, 301-977-1398, fax 301-869-7033

There are undoubtedly others.

The best price I have been offered was $USD 865.00 for the Pioneer
DRM600 (cheaper than with a PC interface card which you don't
need) and no driver. A driver from some Canadian company (Instar ?)
was offered for about $400 more I think. These prices were from

So what am I going to do ? Take my test unit back where it belongs,
buy one myself, without a driver, and if I discover the driver does
something useful, then I'll buy that separately. Of course if I
discover that the new DRM604X quad speed XA multisession drive just
plugs in too, then I might buy that instead ... stay tuned.

What would I do if I discovered I was one of the many people who
may have been misled into buying an expensive driver I didn't
need ? That isn't printable, even in an "alt" group ! I would
certainly be asking for my money back from the vendor !


David Clunie (

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