Original message:
> From randy Wed Apr 7 13:25:57 1993
> To: sun-managers@eecs.nwu.edu
> Subject: SPARC10 SCSI cable length
> Content-Length: 990
>
> We have a SPARC2 with 5 external and 2 internal peripherals attached to
> the main SCSI bus. The total external cable length is approximately 12 feet.
> When I tried to configure a SPARC10 with the same setup, it wouldn't boot
> until I removed two of the external devices. This brought my total
> external cable length down to about 9 feet, much less than the 6 meter total
> Sun says is OK. A third party vendor told me that with the fast SCSI
> devices, the total cable length limit is probably closer to 10 feet.
>
> Does anyone have any concrete information on this hypotheses? Also, would
> the length of a single cable have an affect?
>
> +----------------------------+----------------------------+
> | Randy J. Ott | randy@sisdbell.Logicon.COM |
> | Logicon, Inc. | (402) 291-7750 (Voice) |
> | 1408 Fort Crook Road South | (402) 291-2503 (Fax) |
> | Bellevue, NE 68005 | |
> +----------------------------+----------------------------+
>
Following is a summary of what the problem might be:
1. Don't forget to add the interal cable length for devices attached.
Interal lenghts most commonly range from .5m to 1.0m, which could put
me over the 6m limit.
2. Make sure none of the devices are terminated themselves.
3. Make sure that the terminator is an "Active SCSI terminator".
4. Use high quality cable: 28AWG 7/36 stranded, polyolefin (not pvc)
insulated, 80ohm.
5. Check for poor connections between devices.
I have ruled out 1, 2, and 5. I believe I have an "Active" terminator
attached, but I'm not certain. Some of my cable is not labled, so there
may also be a problem there.
I believe these suggestions should fix my problem.
Many thanks to,
Stefan Mochnacki <centaur.astro.utoronto.ca!stefan@ucsd.EDU>
alkestis.mpim-bonn.mpg.de!sven@ucsd.EDU (Sven Maurmann)
nelson.fernandez@att.com (Nelson Fernandez)
lsr.nei.nih.gov!art@ucsd.EDU (Art Hays - PSTAFF)
kudzu.astr.ua.edu!crock@ucsd.EDU (Deborah A. Crocker)
"Michael R. Zika" <fatman.tamu.edu!zika@ucsd.EDU>
netcom.com!mikey@ucsd.EDU (Mike Pechner)
nucmed.NYU.EDU!hkatz@ucsd.EDU (Henry Katz)
masc38.rice.edu!canuck@ucsd.EDU (Mike Pearlman)
+----------------------------+----------------------------+
| Randy J. Ott | randy@sisdbell.Logicon.COM |
| Logicon, Inc. | (402) 291-7750 (Voice) |
| 1408 Fort Crook Road South | (402) 291-2503 (Fax) |
| Bellevue, NE 68005 | |
+----------------------------+----------------------------+
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