Emulex MD21 vs. Adaptec ACB4000
Jeff Weber
ulowell!cg-atla!weber at harvard.UUCP
Mon Apr 24 14:24:59 AEST 1989
aad at stepstone.com (Anthony A. Datri) writes:
>I see that there are different sets of supported disks under these two
>controller types in Sun's 4.0 format.dat file. The Micropolis 1355 is
>listed under the MD21, yet I have a Sun sheobox with a 1355 attached to an
>Adaptec. Is this division as arbitrary as it seems? I want to take a DEC
>rd53 (really a Micropolis 1325), and hang it as the second drive off of
>the MD21 in a Sun shoebox that already has a 1355 in it. I suspect that
>this'll work just fine as long as I add an entry for the 1325 off of the
>MD21.
Interconnect stuff deleted...
First off the MD-21 is a SCSI to ESDI controller and abotu twice as fast
as the Adaptec 4000 which is a SCSI to St-506 controller. ST-506 and ESDI
are traditionally disk interfaces and ESDI is twice as fast as ST-506
(send nit contradictions to /dev/null).
You cannot intermix the drive and controllers just because the cables fit,
which they do. I'm pretty sure that experimentation will lead to the
purchase of a disk or controller. A 1355 is a 327MB(f) ESDI disk and a
1325 is a ~85MB(f) ST-506 disk.
MD-21's don't like to have two different configurations of disks attached
let alone an ST-506 added in for good measure. I'd check that you have a
1355 ESDI connected to a ST-506 Adaptec. Something is not right is that
is INDEED the situation (is it really a Adaptec 4000?) and not some
non-4000 controller.
Jeff Weber
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