SUMMARY: SS2's, SunOS4.1.1 and Exabyte tape drives

From: John Valdes (
Date: Fri Jan 11 1991 - 17:48:04 CST

Yesterday, I described a problem I was having connecting an Exabyte to a SS2.
As it turns out, the problem was a SCSI id conflict; both the external disk
and the Exabyte were set at id 1. There are three jumpers on the back of the
Exabyte which control the scsi id (you may have DIP switches on yours). What
happened was that I was reading them in reverse; instead of reading them
right-to-left (when facing the back of the drive), I was reading them left-to-
right. (My mistake was assuming that the jumper labeled "1" on the PCB and the
jumper labeled "3" on the PCB corresponded to SW1 and SW3, respectively, as
described in the Exabyte manual when it is actually the other way around--silly

The "probe-scsi" prom monitor command (thanks to Dan Strick) is useful for
checking which scsi devices are present to Sun w/o having to go though the
booting sequence. On the SS2 (and probably SS1) this is done by entering "n"
at the monitor prompt (ie, '>' after L1-A or halt) followed by entering

With regards to my other questions:

>1) Does the SS2 have an internal terminator which has to be removed?

  No. From Timothy G. Smith:

>You don't have to worry about the inside of the box. It is handled
>automagically via hardware.

>3) Finally, what do the lines
> esp0: Target 3 now Synchronous at 4.0 mb/s max transmit rate
> esp0: Target 1 now Synchronous at 4.0 mb/s max transmit rate
> mean? Is the SS2 using synchronous transfer mode for the scsi bus?

Again, from Timothy G. Smith:

>The kernel figures out synch mode on a per drive basis and is a good
>thing. Use it if you got it. You don't have to worry about ASYNCHIO
>in the kernel- it has nothing to do with SCSI stuff.

Thanks to those who responded: (Daniel Strick)
tgsmith@East.Sun.COM (Timothy G. Smith) (Joe Garbarino)
oconnor!trinity!miker@oddjob (Mike Raffety)

Also thanks to those you tried to respond but couldn't because of my messed-up
return address.

John Valdes
University of Chicago

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