by >I am about to add a second internal SCSI disk drive to my controller.
>The first one has SCSI ID 1 and the second one arrived set to SCSI ID 6.
>(I presume there is no problem with that.) My question is:
>How do I tell DOS that I have a new disk drive, and how will a drive
>letter be selected for it? I can't find any evidence of how DOS
>was told that my first SCSI drive exists and should be drive C:.
>The reason it doesn't seem possible for DOS to figure this out
>automatically is that, with SCSI disks, you tell the BIOS that you
>don't have any hard drive C: or D:. So it is unclear how DOS finds
>out about such drives.
>Can anyone give me a clue here?
physical hard drives without a device driver in CONFIG.SYS. V5.00 and
V6.00 support up to 8 physical disks. DOS determines the physical
disks via INT 13h which means the SCSI adapter must have a BIOS capable
of advertising greater than 2 hard drives. Make sure your adapter can
do this. The limit of 8 may be only FDISK's limit and DOS itself may
handle more.
Yes, it is really true for SCSI at least. I've never paid anyQuote:>Secondly, the manual tells me that the first and last device on
>the SCSI cable must have termination resistors, and the rest must
>not. Is this really true? The same manual told me that this was
>true about two floppy drives on the same cable, and I ignored this
>and they both work fine. But maybe SCSI devices are more sensitive
>to this rule? Anyone have any experience with installing multiple
>SCSI devices?
attention to floppy drives though, but I am experiencing some wierd
problem right now which I will look into the next time I open up the
system.
I had a SCSI setup which was working fine for a long time, then I moved
my monitor and put a fan on my desk (it was a hot summer day). I
couldn't boot my system anymore. I was baffled. I made no system
changes to the SCSI bus, no hardware changes, no CONFIG.SYS or
AUTOEXEC.BAT changes. I called in a co-worker, and he immediately
noted the problem. The last hard drive on my SCSI bus was never
terminated.
Moral: Just do it. It may save you grief later. I now have 2 SCSI
adapters, 2 hard drives, 1 magneto-optical, 1 DAT, 1 CD-ROM on the same
SCSI bus. All correctly terminated and no SCSI related problems so far
(just driver problems :-).
rp93
PS: Do not connect 2 SCSI adapters to the same SCSI bus unless you know
exactly what you are doing. DOS and all other OS's expect each drive
letter to be unique. I juggle with device drivers to allow all hard
drives and optical to be controlled by one adapter and DAT and CD-ROM
to be controlled by the other.
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