Possible Bug in SCSI disk detection on BIOS-less adapters in at least 2.0.3[45]

Anthony Barbachan (barbacha@trill.cis.fordham.edu)
Thu, 30 Jul 1998 00:30:12 -0400

I have been having trouble trying to get either an Adaptec 1510a or Future
Domain TMC-1610MER to reconized three SCSI disks. Using Adaptec's AFDISK
utility I found that, at least the Adaptec, was able to see all three drives
so the problem had to be located in the Linux driver somewhere. Under Linux
my Adaptec 1542cf was able to see all three drives and I suspect most people
with more than three SCSI drives probably use a SCSI card with a BIOS, so I
suspect the detection on BIOS-less adapters, which both the 1510a and the
1610 happen to be and the 1542cf isn't, is not working correctly. When
looking through the source of the Future Domain driver I saw some old SCSI
detection code that had been removed from default compilation by an
#if...#endif block. After reenabling this code, the Future Domain was able
to see and use all three SCSI drives. According to its programmer's
comments the old detection code had been removed because earlier problems
with the SCSI detection code had been fixed in scsi.c. This code had been
slated for removal in the near future, fortunately the programmer had
decided to keep it around just in case. In any case this is a reproducable
event with two different SCSI adapters that goes away on one of them if it
is told to use an alternate SCSI detection code. So it appears to be a bug
in the SCSI detection code.

- A. Barbachan

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