On Fri, 11 Oct 1996 12:28:52 +0300 (EEST) 
 Jari Kokko <jkokko@tnso13.tele.nokia.fi> wrote:

 > I tried to connect a second Micropolis 1558 ESDI to one of my Emulex
 > MD-21's... It didn't work. 

It Just Works on my sun3:

si0 at obio0 addr 0x140000 level 2 : options=1
scsibus0 at si0
sd0 at scsibus0 targ 0 lun 0: <EMULEX, MD21/S2     ESDI, A00> SCSI0 0/direct fixed
sd0: 135MB, 823 cyl, 10 head, 33 sec, 512 bytes/sec
sd1 at scsibus0 targ 0 lun 1: <EMULEX, MD21/S2     ESDI, A00> SCSI0 0/direct fixed
sd1: 312MB, 1224 cyl, 15 head, 34 sec, 512 bytes/sec

 > I can't imagine how I could cable it wrong, and I don't think I need
 > to set any jumpers either.
 > 
 > When the two LUNs were both present, the kernel could only find the
 > first, and after mounting that, I kept getting soft errors and when
 > grepping the Sun HW FAQ for MD-21, the system seemed to hang: both
 > Micropolises flashed their leds seemingly in unison.
 > 
 > Do I need to make a twist in the data cable for one of the disks a'la
 > PC floppy drives? The HW FAQ only mentions 'daisy-chaining' the data
 > for the disks.

I don't recall having to do this either; there's a separate control cable
for the second disk.

Definitely sounds like something's wrong, tho :-)  Hopefully, you can
find someone with MD21 docs...

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
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