In message <10cs30vqh64u6df@news.supernews.com>, Ghostrider
<-00-@fitron.142> writes
>
>John C wrote:
>
>> I have inherited a PC system running Windows NT and a SCSI CDROM. When
>> the CDROM is not connected the system always (I believe) boots OK but
>> when it is connected it sometimes hangs as the Windows desktop is
>> displayed.
>> I've looked in the SCSI adapters setup and it says: Adaptec
>> AHA-29xU2/295xU2/395xU2… and IDE CD-ROM (ATAPI 1.2)/…
>> Does anyone know why this may happen?
>> Thanks,
>> John C.
>
>The problem is less likely the SCSI controller but more
>of one being contributed by a desktop application or a
>startup application that is looking for something in the
>SCSI cdrom drive or that of the drive letter that is used
>by the SCSI cdrom drive when it is connected.
>
Is the SCSI CD-ROM the only SCSI device on the controller.

If it is I would guess that the issue is termination of the SCSI bus.
SCSI Buses need to be properly terminated at both ends otherwise all
sorts of strange things happen.

I think that with the CD-ROM disconnected NT is told by the controller -
no devices, and consequently never investigates as it starts up. If the
CD-ROM is present, NT interrogates to see if there is a disk in it while
booting - and the SCSI bus (sometimes) hangs.

Check that the controller end is terminated ( an option on the card
somewhere- or in the SCSI BIOS (usually Ctrl/A during boot)), and that
the either the CD-ROM provides termination, or there is another
terminator on the bus.

If the CD-ROM is not the only device on the SCSI Bus, then possibly the
problem is an incompatibility between the CD-ROM and the rest of the
Bus. Check the configuration of all the devices are consistent (inc.
SCSI ID's ). I have also had problems with having a differential drive
and single ended drives on the same BUS.
--
Peter R Cook