Bill,

My experience with SCSI termination has been that if the SCSI bus is
terminated with the first drive then anything after the first terminated
drive would not be recognized in either the SCSI bios or by the system.  I
have always used the "Term Power from Drive" with no problems.

Actually I am more concerned with the small power supply, 235w that he is
using.  I had problems with a 250w power supply and 3 drives.  I bought a PC
Power & Cooling 400w power supply for my 3 SCSI drives.  I also have 2 cd
roms and the normal adapter cards on the motherboard.  On the 250w power
supply I had many GPF's, partitions that diappeared and could not be written
too, and the occassional disappearing drive on cold boots, the last drive
would disappear and then my SCSI bus would not have the proper termination.
I replaced the power supply and all of my problems have disappeared.  If the
system works fine with one SCSI drive, then add another and it still works,
add the third and see if you start having problems with the second or third
drive.  I would then suspect the power supply is not sufficient for your
needs.

Mary Wolden

From: Bill Cohane :Subject: Re: [PCBUILD] SCSI drive install


> Original message (slightly trimmed) below.
>
> Hi Brad
>
> I hope that the drive coolers are the "two-fan 3.5" to 5.25" bay cooler"
> type and not the "little heat sink with fan" type. I consider the later
> inadequate by itself for fast spinning drives. To answer your questions:
>
> (1) The 2940UW will supply power for termination so I'd set all drives to
>      "Term. Power from SCSI bus". I don't see how "Term. Power from drive"
>      (the default) would cause you problems though. Just don't have the
>      drive set for "Term. Power to SCSI bus" as having too many devices
>      doing this could cause problems.
>
>      Since you have the IBM drive at the end of the chain, please make
>      sure the two Seagate drives have their TE jumpers removed. This
>      could be your problem...having two drives terminated could work
>      (very poorly) at lowest speeds (only). Check that the TE jumpers
>      on the Seagates are removed. Then check again. Make sure that you
>      are looking at the correct pins (not ones at the wrong end of
>      the jumper block). <Snip>
>      Your Granite Digital cable is of good <Snip>
>      The cable should be less than 5 feet long. <Snip>
>      What BIOS does your 2940UW have? I recall that one of the newer
>      versions had problems. <Snip>>
>      >
>      If necessary, remove the IBM drive and see if the Seagates work
>      one at a time and then together. Be careful about SCSI IDs and
>      Termination. Make sure you have a drive at the end of the cable.
>      (Having a length of cable tailing out after the last drive is
>      not advisable.)
>
>      When all three drives work together, set the drives so one of the
>      Cheetahs has ID=0 and the drive at the end is the only terminated
>      drive.
>
> Let us know how things go!
>
> Regards,
> Bill
>
>
> At 21:11 1/13/2000 , Brad Loomis wrote:
>  >System is ABIT BX6, PII233, 64MB, Adaptec 2940UW.
>  >4.5GB UW IBM
>  >http://www.storage.ibm.com/hardsoft/diskdrdl/prod/9esprod.htm
>  >two Seagate 4.5GB ST34501W  [Cheetahs]
>  >http://www.seagate.com/support/disc/scsi/st34501w.html.
>  >
>  >They are [all] 68 pin SE drives. I tried to set it up as ID 0 Seagate,
>  >ID 1 Seagate, ID 2 IBM, with the IBM having the termination jumper
>  >installed. They are cabled in that order from host to IBM, Granite
>  >Digital cable, All are recognized in the Adaptec BIOS scan. All have
>  >PC Power & Cooling Bay coolers.
>  >
>  >I started...with the transfer rate at 40. I got many error messages...
>  >I reset the rate to 10MB transfer and was able to get things installed,
>  >but not without some trouble...
>  >Windows took over two minutes to boot and was not pleasant to use. I
>  >never was able to get Office97 installed. I tried to set up a FAT32
>  >swap partition on the second Seagate with Partition Magic 5.0. The
>  >partition was made, but every time I tried to set my virtual memory,
>  >windows would report the drive as being 0 MB.
>  >
>  >I also tried to set the jumpers on the drives to spin up from the host
>  >to take some strain off the power supply, 235W, marginal I know.
>  >
>  >My questions are,
>  >
>  >1. The Seagate have a jumper for Term. Power, if they aren't
>  >terminated, do I leave this jumper on? There are three choices for
>  >settings. I can find no explanation for their function. They are Term.
>  >Power from drive (default), Term. Power to SCSI bus, Term. Power from
>  >SCSI bus (position A), and Term. Power to SCSI bus and Drive.
>  >2. Should I use the motor start from host option?
>  >3. Is Dos unable to run at the fast transfer rate? Or is there some
>  >other possible problem?
>  >4. Should I install the drives one at a time and re-jumper as I go to
>  >try to get things to work?
>

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