On Mon, 10 Mar 1997, Rick GC wrote:

> Hi list,
> 
> I am currently running Netbsd on a uVax 3600 with one RA82 and have aquired
> a SA482 (four RA82's).  I would like to know if anyone could give me some
> ideas about how to best connect/chain them up.  I noticed that the 3600 has
> connectors for four drives (0, 1, 2, 3) or at least that is how it appears.
> Also each drive has two switches(A and B) and synching connectors(on the
> back/little round guys) which leads me to believe that the drives can be
> chained and synched.
> 
> Rick GC  
> 
> 
The disks are dual ported (Port A and B). This makes it possible to 
access the drive from two different sources (one at the time). If A or B
is in the inner position it will answer requests on that port. In the outer
position it will ignore requests. In a cluster environment it is possible to
have a disk with both ports active connected to two different HSC:s and one
HSC will take over the drive if the other HSC fails.

One port in the 3600 is one disk in the SA482.

The synching connector is for chaining powerup of the diskdrives. To reduce
the possibility of blowing fuses if a machine and all it's disks is starting
at the same moment. I don't think I've seen this feature used in the last 
ten years.

-moj

------------------------------------------------------------------------------
Mats O Jansson, CelsiusTech Systems, Jaerfaella, Sweden
email: maja@celsiustech.se (or moj@stacken.kth.se)