🚀 go-pugleaf

In article <17869@umd5.umd.edu>, bleau@umdsp.umd.edu writes:
> 1)  I just found out that the 1st SCSI bus on teh VS3100-76 is internal only
> and can't be extended beyond the system box.  That limits me in that all my
> additional scsi devices have to go on the 2nd bus.  Can anyone confirm or deny
> this statement?  I got it from DEC, btw, but you never know.  Also, is there a
> non-DEC way of feeding it to the outside world?

  I believe the M76 uses the same SCSI/SCSI adapter as the M38/48. If so, the
following may be useful:

  The baseplate has 3 mounting positions. The rear right contains the SCSI
adapter. The front right handles a 1/2 height 5.25" device, either a TZ30
or an RX2xS, which is run off the B SCSI bus (the "external" one). The 2
left positions can each handle 3.5" full-height drives, and are run off the
A bus (internal). However, there are 3 connectors crimped on the A cable,
so you can use the 3rd one to run the front right device, giving you 7 free
ID's on the external bus.

  As far as getting the A bus out of the box, I wouldn't do it. The cable is
somewhat unusual in that it loops back into the connector (which has 100
pins) and the terminators are on the SCSI adapter itself.

> 2)  I was warned by a 3rd party disk vendor to stay away from SCSI id 7.  He
> said that DEC has their cpu at scsi id 6, and that some devices will work at
> scsi id 7, but they get a little flakey, and he gave the impression that it'd
> be a bad idea to depend on devices at that id.  He also mentioned that this bug
> was fixed in the VS4000-60.  Can anyone confirm or deny this bug, and give more
> specifics on it?  Also, can you comment on if it has really been fixed, or is
> it still lurking; ie, am I safe in putting scsi devices (or even the scsi
> adapter) at scsi id 7?

  The SCSI adapter's ID's are individually settable to any number. Using a
device with a higher ID than the adapter (and thus a higher priority) can
indeed cause problems. You can reconfigure the adapter's ID using the built-
in ROM code, so it's not a problem.

> 3)  I was told the the VS3100-76 only has scsi-1, not scsi-2.  If I buy a
> disk drive with a scsi-2 interface, what can go wrong if I attach it to the
> scsi-1 adapter on my system?

  I haven't had any problems running Fujitsu M2624's which are SCSI-2 in a
M38. Of course, the adapter doesn't do sync mode. However, it all works fine.
3 of the new(ish) Fuji 1Gb 3.5's can be put in the M38 box if you don't need
a floppy or tape in the front right position, thus giving you 3Gb internally.

> 4)  I have an internal TZ30, but it's on the 2nd scsi bus.  Is there a way I
> can put this on the 1st scsi bus?  Some special, but easy to get, cable maybe?
> If you have a part number, that'd be great (are you listening, DEC field
> service?).

  See my answer to #1, above.

	Terry Kennedy		Operations Manager, Academic Computing
	terry@spcvxa.bitnet	St. Peter's College, Jersey City, NJ USA
	terry@spcvxa.spc.edu	+1 201 915 9381