I got one of the $20 CD-ROM drives from the online auction Phil Nelson
posted info for.

I hooked it up to my pc532; At first I didn't get anywhere.  cd0a gave
an I/O error on open, reading rcd0a gave the contents of rsd0a.  Turns
out the MAKEDEV script needed a tweak;

pc532# diff MAKEDEV.0 MAKEDEV
225c225
<       cd*) name=cd;   unit=${i#cd};   chr=4;  blk=12;;
---
>       cd*) name=cd;   unit=${i#cd};   blk=4;  chr=12;;


The drive appears to be a model OEM'ed for IBM (it says so right on the
label, and in the IDENTIFY data);

cd0 at scsibus0 targ 6 lun 0: <IBM, CDRM00201     !F, 0724> SCSI2 5/cdrom removable

This concerns me a little; I hope they didn't change too much
firmware.  The features I care about are the ability to read raw audio
data, and the feature where if you cut the traces between two half-pad
pairs the drive comes up in 512-byte block mode, and can be used to
boot old Suns..

I built the FreeBSD libscsi.a and used it to build "cdd" a program
that can copy CD audio tracks, using proprietary commands (support
Toahiba drives).  It reads the TOC, but transferring audio data fails.
It could be an ncr driver problem or my questionable SCSI bus wiring;

    # ./cdd -t 15 .

    ............. toc stuff ............

    Copying only track 15

    Copying AUDIO track 15 to ./track-15.cda

    Mode changed to 2352 bytes/sector

    ncr0: too much data padding
    ncr0: aborting, but phase=DATA_IN (reset)
    ncr0: reset SCSI bus for TID=6 LUN=0

    SCSI Command failed on lba 123470

    Unable to read CD-DA at lba 123470
    SCSI Command failed: Change Block Size to 2048
    Unable to exit CDAudio Mode

I'd be interested in knowing how the drive behaves with cdd (or a
similar program named "tosha") on FreeBSD (or even NetBSD/i386).

-phil