[comp.periphs.scsi] Adaptec 1542b & Emulex MD21's

kncarp@nicsn1.monsanto.com (06/08/91)

My Adaptec 1542b arrived Friday, I quickly installed it and ran through the 
internal checks without anything plugged in and all looked good.  DMA ran
at the default 5.77 rate but busted faster than that, which is OK.

Since I didn't have a matching external cable (I was expecting a standard
50 pin D-Shell connector, the 1542b comes with a centronics connector), I
opened my external case and rigged both drives off the included internal cable.
Powered everything up and no drives were found.  Stripped everything out of 
the computer except the VGA card and a serial card and still couldn't find
any drives.  Did test the floppy controller part of the 1542b - it worked fine.

I did notice that the red LED stayed on continuously after it probed for the
disk, the documnetation indicated that this was probably due to SCSI bus
errors.  Brought the box in to work today (Saturday) and hooked it to my
Sun Sparcstation and issued a "Probe-SCSI" command from the monitor.  The 
monitor reported my normal internal disk and the two Emulex MD21 ESDI->SCSI
controllers, each supporting LUN 0 & 1. (For the record, I changed the SCSI-ID
of one of the drives to SCSI-ID 2 so that it wouldn't conflict with my Sparc
internal drives).  When I rebooted the Sun kernel, it faithfully reported the
internal drives and the two Micropolis 1355's that are on each MD21's LUN 0.
  
Now I've heard that the old MD21 based disk won't work on Sparcs,and sure 
enough I started getting SCSI errors when I actually tried to use the system,
but that wasn't a surprise.  Both drives came off of Sun 3/110 and Sun 4/110
equipment where they were working two weeks ago.
  
My questions are (finally): 
  
1) Does anybody know what the single bank of DIP switches do on each of the
   MD21 controllers?  Clearly 3 are used to set the SCSI ID, what about the
   rest?
  
2) Has anybody gotten an 1542b to work with an MD21 front-end to ESDI drives?
   Any special jumpering on the 1542b?  I've tried playing with both the
   Syncronous Jumper and the Parity Jumper - no go with either.
  
Thanks in advance, answers either here or by e-mail.

Kevin Carpenter
kncarp@nicsn1.monsanto.com