Adding third Sun shoebox to 3/60

[Neil Gorsuch]

In article <12012 at umn-cs.CS.UMN.EDU> dre at umn-cs.CS.UMN.EDU (Douglas R. East) writes:
>1.  Can more than two shoeboxes be placed on the SCSI port? ...
>2.  If more than two can be on the bus, how do you set the target and unit
>inside the shoebox? ...

Sunos allows 4 SCSI addresses to be used for disks.  On certain models,
such as 3/50's and 3/60's, you can put up to 2 disks per SCSI address.
These are usually ST506 drives that are interfaced to SCSI via an Adaptec
board, or ESDI drives that are interfaced to SCSI via an Emulex MD21
board.  To see how many SCSI disks can be can be used, look at file
/usr/sys/sun3/OBJ/sd.h, this will tell you how many static sd structures
are allocated in the kernel.  Sun 3's allow 4 disks in Sunos 4.0 or later,
and I seem to recall only 2 allowed in earlier versions of SUnos.  For the
Sun models that support ESDI and ST506 drives, this is the correspondance
between device names and SCSI addresses:

device	scsi	lun	kernel specification line
name	address		to include this drive

sd0	0	0	disk sd0 at si0 drive 0 flags 0
sd1	0	1	disk sd1 at si0 drive 1 flags 0
sd2	1	0	disk sd2 at si0 drive 8 flags 0
sd3	1	1	disk sd3 at si0 drive 9 flags 0
(The previous 4 lines come from the GENERIC kernel, which allows up to 2
SCSI drives, or up to 4 ESDI or ST506 drives, or a combination.  The
next 4 lines should be added if you want to be able to use up to 4 SCSI
drives or use ESDI or ST506 drives at higher SCSI addresses.)
sd4	2	0	disk sd4 at si0 drive 16 flags 0
sd5	2	1	disk sd5 at si0 drive 17 flags 0
sd6	3	0	disk sd6 at si0 drive 24 flags 0
sd7	3	1	disk sd7 at si0 drive 25 flags 0

Some Sun models, such as the 386i, are supplied with direct SCSI interface
drives as the official Sun drives, so the numbering scheme is a little
different:

device	scsi	lun
name	address

sd0	0	0
sd1	1	0
sd2	2	0
sd3	3	0

The Adaptec and Emulex boards both have switches to set the SCSI address.
The Emulex board can connect to one or two ESDI drives, with the lun of
each being determined by which connecter is used.  If the shoebox that you
have has room and another power supply connector, you can usually add
another drive to it yourself.  We have configured and sold systems that
include 4 600 Mb direct SCSI interface drives and 2 different tape drives,
all off the same 3/60.  2.4 Gbytes of disk and 2.36 Gbytes of tape, not
bad for a 3/60 :<).  Various places sell drives and/or shoeboxes,
including us.  Call me for details on setting the address switches, or
contact Emulex and/or Adaptec.   Currently, direct SCSI interface drives
are probably a better deal as add-on drives, and most SCSI interface
drives can work with most Sun workstations, it's just a matter of knowing
what to tell diag or format.  The ESDI drives are comparable in speed to
SCSI, in fact, they are frequently the exact same drive with differing
interface electronics.  The ST506 drives are much slower, as a rule, than
SCSI or ESDI drives, in access time, as well as being a much slower data
transfer specification.

> ...  I can't find anything in the documentation I have
>that shows how to set up the jumpers.  The two shoeboxes currently on the
>3/60 are targets 0 and 1, both units 0 (this corresponds to drives 0 and
>8).  The extra shoebox is configured as target 1, unit 0 (drive 8).  I
>would like to configure it as target 0, unit 1 (drive 1).

That should work fine, but you don't need to bother changing the second
drive, just add the other drives at higher addresses.  Just don't forget
to do a ./MAKEDEV sd- in /dev for whatever drive you are adding if it
isn't already there, and re-build the kernel if needed with the extra
configuration lines.

>3.  If 2. is possible, does the last shoebox (presumably target 0, unit 0)
>need to be terminated in any way?

Each end of the SCSI bus should be terminated.  The Sun workstation
provides termination for one end, the last disk (or interface board if the
disks are ESDI or ST506) or tape drive should be terminated.  There is
either a pair of dip resistor packs, or 2 or 3 sip resistor packs that are
removable.  Direct SCSI interface drives almost always have a pair of
jumpers that determine where the termination power comes from.  These have
to be set correctly, since the 3/50 or 3/60 (I can't remember which this
late at night) shorts the SCSI line that is normally reserved for
termination power.

Hope this has been of help.

Neil Gorsuch
Uninet Peripherals
neil at cpd.com
uunet!zardoz!neil
(800) 433-6784 outside California
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