3rd Party SCI Disks

[George Robbins]

In article <15166 at dartvax.Dartmouth.EDU> steve at avalon.dartmouth.edu (Steve Campbell) writes:
> We are considering purchasing a larger DEC RISC processor (5810), and
> are thinking of buying 3rd party disks.  Emulex offers a disk stack
> containing their SD891 drives, which are CDC drives with an Emulex
> module attached.  Emulex claims that the result is an MSCP/SDI-
> compatible unit that can be controlled by the KDB50 just like a DEC
> drive such as an RA90.  Would anyone care to comment on whether this
> will work under Ultrix 3.X?  If not, why not?

Basically, if the drives/controller emulate *exactly* a standard DEC drive,
then it should work.  If they make like some kind of generic MSCP disk with
random size, they may work.  If not, especially if Ultrix doesn't see the
drives as *normal*, you may have a real uphill battle.

I'd advise a traditional approach: get a least one DEC drive so that you
can build/boot the system without adventure and so that DEC needn't be
confused by compatibility issues.  Second, make sure that you can arrange
to return the 3-rd party drives if you are unable to get them to work
with Ultrix in a finite length of time - make sure the decision is up to
*you*, not the vendor or resaler.

Warning: Emulex technical support knows next to nothing about Unix and
less about Ultrix.  Obtain references or a commitment for an Emulex
engineer to be available to resolve problems...

Maybe someone else has already been brave, and you need not worry about
these things.  I put an Emulex/CDC Sabre setup on a VAX 785 and found it
a do-it-yourself adventure, plus more fun each major release.

> We have also heard that although the KDB50 can nominally run up to 4
> disk drives, there is a performance penalty if more than 2 are connected.
> Again, can anyone comment?  Any specific figures on the penalty?

I hadn't heard that, but I'd be curious about any responses you get.

> Steve Campbell - Dartmouth College
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-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
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