From: CMATT@ocvaxa.cc.oberlin.edu (Matt Gilbert)
Newsgroups: comp.os.vms
Subject: DSSI mysteries explained
Date: 23 Jul 92 18:33:00 GMT
Distribution: world
Organization: The Internet


  Here is what I have learned from all you folks out there and from spending
lots of time at the console prompt. The documentation that came with my 
KFMSA's and my DECarray (RF disks) was (as usual) pretty useless.

  A DSSI disk can be thought of as a single disk connected to a single HSC 
and served to it's host. This means that EACH DSSI disk (ISE) is an HSC and 
a disk. So, each ISE has it's own nodename (which must be unique), allocation
class and a load of other parameters. All DSSI disks show up as device
DIAxxx no matter how many DSSI controllers you have or how they are hooked up.

  The parameters you will be most interested in setting will be:
    allclass - allocation class (should match the host VAX's)
    unitnum  - the device's unit number (ie. $1$DIAxxx)
    forceuni - set to 0 if you have changed unitnum
    nodename - any alphanumeric string up to 8 characters

  Each KFMSA has two I/O paths (bus 1, bus 2). It is very important that you 
know which disk is on which bus. It is also very important that you know 
which XMI slot your KFMSA is in as well. You need all this information in 
order to tell your 6000 how to boot:

   BOOT /XMI:A /DSSI_NODE:0 /PORT:1 DI0

  Here we see that we want to boot from a KFMSA in XMI slot A on DSSI_NODE 0
(more about that in a minute) PORT (more like BUS) 1 device DI0.

  We can find the XMI slot out by doing a show config at the console prompt
or by looking in the XMI card cage.
>>> SHOW CONFIG
      Type           Rev
  1+  KA66A   (8087) 0005
  2+  KA66A   (8087) 0005
  9+  MS65A   (4001) 0084
  A+  KFMSA   (0810) A4A6
  B+  KFMSA   (0810) A4A6
  C+  KDM70   (0C22) 1911
  E+  DEMNA   (0C03) 0802

  In my particular case you will notice 2 KFMSA's one at XMI slot A and another
at slot B. You can now see that it is very important for you to have a good
understanding of how your DSSI drives/controllers are configured. Don't just
let DEC hook them up and then forget about it. The best method of seeing how
things are hooked up is by running diags. Specfically the autosizer and then
the DSSI configuration program called EVCXF (this program is only available
on the complete diagnostic kit, not the customer diags - get it from DEC and
make sure you put a copy of it on your system, it is one of those mandatory
type of programs that DEC should have given us in the first place). This 
program is also used to configure your ISE parameters. Output is show below

DSSI sizing underway, please wait...


             XMI node 0A      XMI node 0A      XMI node 0B      XMI node 0B
DSSI ID       Bus 1/UUN        Bus 2/UUN        Bus 1/UUN        Bus 2/UUN
  0           RF35    1       *****             RF35    9       *****
  1           RF35    2        RF73    7        RF35   10       *****
  2           RF35    3       *****             RF35   11       *****
  3           RF35    4       *****             RF35   12       *****
  4           RF35    5        RF73    8        RF35   13       *****
  5           RF35    6       *****             RF35   14       *****
  6          *****            *****            *****            *****
  7          KFMSA            KFMSA            KFMSA            KFMSA


  The DSSI ID column is directly related to the DSSI_NODE qualifier of the 
boot command. So from the above boot command you can see the following:

  I booted a disk at DSSI ID 0 (/DSSI_NODE:1), BUS 1 (/PORT:1) and XMI
slot A. Using this info, you can see from the chart above that I booted
an RF35 UUN 1.

  NOTE: the above chart is the HARDWARE configuration in your machine, the 
UUN is not the unitnum params but simply some number that increments as you
add devices. The unitnum, nodename, allclass is not shown here at all.

  I would highly suggest that you label all your cables and all your drives
in your DECarray cabinet (a good idea at any time). The posibility of not
knowing exactly which physical drive is which VMS device is very likely when
you have 12 disks in the space of one RA90 and there are only two cables
going to them all.

  On the VMS side, set your sysgen parameter ALLOCLASS the same as your 
allclass on your ISE's. Also keep an eye on PANUMPOLL and PAMAXPORT even
if you don't have a CI. VMS thinks these nodes/devices are coming in over
a CI (or at least that is the impression I get) because if you change these
params, you can make devices disappear (trust me on this one, I know this 
from experience - it took me 2 days to find them again).

  And the fruits of this labor:

$ show dev d

Device                  Device           Error    Volume         Free  Trans Mnt
 Name                   Status           Count     Label        Blocks Count Cnt
$1$DIA0:      (ISEA1A)  Mounted              0  VAXVMSV055      684837   139   1
$1$DIA1:      (ISEA1B)  Online               0
$1$DIA2:      (ISEA1C)  Online               0
$1$DIA3:      (ISEA1D)  Online               0
$1$DIA4:      (ISEA1E)  Online               0
$1$DIA5:      (ISEA1F)  Online               0
$1$DIA6:      (ISEB1A)  Online               0
$1$DIA7:      (ISEB1B)  Online               0
$1$DIA8:      (ISEB1C)  Online               0
$1$DIA9:      (ISEB1D)  Online               0
$1$DIA10:     (ISEB1E)  Online               0
$1$DIA11:     (ISEB1F)  Online               0
$1$DIA13:     (ISEA2B)  Online               0
$1$DIA15:     (ISEA2D)  Online               0

  You might also notice that the node names I chose are 6 characters (old 
habits) and in the form ISEabc
         where  a = the XMI slot of the KFMSA 
                b = is the bus they are on (1 or 2)
                c = is what device on the bus (A=1st,B=2nd, so on)

  I don't know if this is going to help me any but it seemed logical and 
lends to unique nodenames.

Thanks for all the help

Matt Gilbert
Oberlin College