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The 7.02 release of the TOPS-10 monitor contains unsupported
code  to  run DMR11s on a KS10.  Although this code has been
used successfully on in-house systems, it is not an official
part of the Monitor.

This document describes the known limitations and advantages
of  using  a DMR11 on a KS10.  It also describes the process
necessary  to  install  and  use  the  software.    Hardware
installation considerations are also discussed.

No representation is made that this document is complete  or
correct  in  all  respects.   Although every effort has been
made by  the  author  to  ensure  its  correctness,  Digital
disclaims  any  responsibility  for  the  use of unsupported
hardware and/or software, whether or  not  such  use  is  in
accordance  with  information contained in this document, or
any other.


Use of a DMR11 in a KS10 represents a  change  to  both  the
hardware  and  software  environment,  and  may  impact  the
perceived performance of the system.

The  DMR11  hardware's  inherent  performance  exceeds   the
ability  of  the  2020  to  drive  it.   As  a  consequence,
configuring a 2020 which includes DMRs requires evaluating a
complex  set  of  trade-offs.   Although  this document will
attempt to present some of the  considerations  involved  in
this  evaluation,  you should enlist the help of a qualified
network analyst in applying them to your situation.

The "standard"  2020  configuration  has  extremely  limited
backplane  space.  It is not possible to install DMR11s in a
maximally configured 2020 system  without  the  purchase  of
additional  hardware.  Installing DMR11s in a smaller system
may limit future expansion.

We strongly urge any site considering installing this option
to  consult  with  their  local  Field  Service and Software
Services representatives prior to making any final decision.
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 2


The  DMR11  provides  the  following  advantages  over   KDP
(KMC/DUP) synchronous interfaces:

      o  The DMR11 supports V.35,  RS-422-A,  RS-423-A,  and
         coaxial cable interfaces, in addition to RS-232-C.

      o  The coax DMR11 can operate over a distance of up to
         6 km (19,685 feet) without an external modem.

      o  The DMR11 will operate in half-duplex  mode.   Half
         duplex  mode  is  supported  by  the  software  for
         DECnet, ANF-10, and Program use.

      o  The DMR11 will operate over  a  switched  (dial-up)
         line, and will provide the necessary modem control.

      o  The DMR11 runs self diagnostics upon startup.   The
         monitor   will   not   use   a   DMR   that   fails

      o  The  DMR11  does  all  DDCMP  protocol   (including
         retransmissions)  without  help  from the KS10 CPU.
         This results in slightly lower overhead.

      o  The  DMR11  can  have   more   than   two   buffers
         outstanding at any one time.

      o  The DMR11 does not require  a  user-mode  microcode


Preliminary testing indicates  that  the  performance  of  a
DMR11  on a 2020 is approximately the same as that of a KDP.
Thus, although the  DMR11  hardware  is  capable  of  higher
speeds  than  the KDP, the DMR should not be viewed as a way
of getting higher network thruput from a 2020.

Setting the speed of a DMR link higher  than  the  2020  can
accept  data  will  cause  retransmissions,  and if taken to
extremes, may cause the other node to declare the link down.
Such  retransmissions  cause  unnecessary  Unibus traffic on
both nodes, and unnecessary KSBus traffic on the 2020.  Such
traffic  can impact the performance of other applications on
the system(s).

Although there is no experimental  data  supporting  it,  we
expect  that the DMR11 may perform significantly better than
a KDP over links which have a high  error  rate,  and  which
pipeline   effectively.   (eg.   Satellite  links)  This  is
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 3

because  the  format  of  network  messages  is  changed  to
accomodate  the  KS10  UBA whenever a message is given to an
interface for transmission.   This  is  a  fairly  expensive
operation,  and  is  one  of  the limits of a 2020's network
performance.  Because the DMR holds  the  buffer  containing
the  external  form  of  the message until it has been DDCMP
ACK'd, the DMR's retransmissions  have  lower  cost  than  a
KDP's.   A  DMR can also manage up to 64 outstanding buffers
(if you can afford the core).


The DMR11 used for a 2020 is  the  same  as  that  used  for
PDP-11  and  VAX  applications.   The  basic DMR11 subsystem
(DMR11-AD)  includes  the  microprocessor  and   line   unit
modules,   documentation,  test  connectors,  and  a  module
interconnect cable.  Customers should NOT order the DMR11-AD
option.   Instead,  one of the four DMR11 packages should be
ordered, depending on the  interface  type  desired.   These

      o  DMR11-AA - RS-232-C/RS-423-A

         The  RS-232-C/RS-423-A  distribution  panel  mounts
         inside   the   KS10  cabinet.   Connection  to  the
         external modem  requires  purchase  of  a  BC05D-25
         cable  for RS-232-C modems, or a BC55D-33 cable for
         RS-423-A modems.

      o  DMR11-AB - CITT V.35

         This package includes a 25  foot  (BC05Z-25)  cable
         that  terminates  in  a  37  pin  DataPhone Digital
         Service (DDS) connector.

      o  DMR11-AC - Integral modem (Coax)

         Interconnecting two DMRs requires  TWO  cables  for
         full  duplex operation.  Only one cable is required
         for half duplex.  For  2020  data  rates,  purchase
         BC55N-98  twinax  cable.   (98  feet  long)  Longer
         cables can  be  purchased  on  special  order  thru
         Digital's Accessories and Supplies group.

      o  DMR11-AE - RS-422-A

         The RS-422-A distribution panel mounts  inside  the
         KS10  cabinet.   Connection  to  the external modem
         requires purchase of a BC55D-33 cable.

KSDMR.BWR - Beware file for KS DMR (non-)support      Page 4


6.1  Backplane Requirements

Each DMR11 requires 2 hex-height SPC slots on  UBA  3.   The
DMR11  can co-exist with KDP lines.  A fully configured 2020
has  no  free  hex-height  slots.    Reasonable   trade-offs
include, but are not limited to:

      o  1 DMR and no KDP lines.  Use slots 2 and 4.

      o  2 DMRs and no KDPs.  Use slots 2,3,4, and 5.   This
         implies  that no more than 24 terminal (DZ11) lines

Of course, it is possible to add a DNHXX-AA/AB expansion box
to  hold  the  DMRs.  In this case, you must order a DD11-DK
backplane, as the expansion box comes empty.  The DNHXX will
be  mounted  to  the left of the current CPU box to keep the
Unibus  length  within  specifications.   This  may  require
changing Massbus cables to disks or tapes.

6.2  Power Requirements

Each DMR11 requires 8 Amps of +5 volts, .1A  of  +15  Volts,
and  .2A  of -15 Volts.  The BA11-K mounting boxes which are
used in the KS10 have  a  capacity  of  50A  of  +5V  (split
between  2  25A  regulators),  4A  of +15V, and 10A of -15V.
Field Service must verify that any DMRs added to a system do
not  require  more  power  than is available in the box, and
that the power capacity of the backplanes  involved  is  not
exceeded.  (A DD11-DK can power no more than three DMR11s.)

6.3  Unibus Loading

Each DMR11 represents 1 Unibus DC  load,  and  5  Unibus  AC

6.4  Address/Vector/Priority

The KS puts DMR11s into the Unibus "user" address  space  in
the IO page.  DMR addresses are assigned starting at 764000,
and proceed sequentially in increments of 10  for  each  DMR
installed.   DMR vectors start at 610.  DMRs are expected to
operate at their default BR level, 5.
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 5

6.5  Installation Considerations

The information presented here  is  intended  to  supplement
that  presented  in  the  DMR11 Technical Manual.  It is not
complete,  and  should  be  used  in  conjunction  with  the
instructions in chapter 2 of that manual.

Backplane  voltages  should  be  checked  with  a  DMM,  and
adjusted  if necessary both before and after installation of
each DMR11.  Both slots of each DMR should be  checked.   +5
is on C1A2, +15 is on C1U1, and -15 is on C1B2.

The NPG backplane jumper must be removed from CA1-CB1 of the
backplane   slot  used  for  the  microprocessor  (M8207-RA)


               Failure to remove this  jumper
               may  damage the M8207, as well
               as result in incorrect  system

6.6  Jumpers and Switches

6.6.1  M8207 (Microprocessor Module) -

The "normal" configuration  from  the  technical  manual  is
correct, except with respect to addressing.  The KS does not
use floating addresses for the DMR.  See above.

Thus, W1, W2 are installed.  E28-7 is ON, E28-8 is OFF,  and
E85-1 is ON.

6.6.2  M8203 (Line Unit Module) -

Jumpers should be exactly as specified in table 2-8  of  the
technical  manual.   Note  in  particular that W17 should be
OUT, even for "half duplex" operation.  Some DMRs have  been
known to arrive mis-jumpered, so check!

Switch pack E39 - set per customer requirements.

Switch pack E121 - SW1-8 should all be ON.  SW9-10 should be
ON,  unless  a DMC is on the other end of the link, in which
case SW9 is OFF and SW10 is ON.
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 6

Switch pack E134 - SW1-8 should all be OFF.  SW10 should  be
OFF.   SW9  should  be  ON  for  non-switched lines (eg null
modems, leased lines), OFF otherwise (dial-up).   Except  in
unusual  cases,  everything  will  work with SW9 OFF even on
non-switched lines.

For DMR11-AAs, refer to table 2-13 (p 2-27) for distribution
panel jumper selections.

For DMR11-ACs, Make sure that the terminators are  installed
per  figure  2-7  or  2-8  (p  3-35/6).   Note that only one
terminator is installed per cable, and that it goes  at  the
RCV  end.   Also  ensure  that  the  HDX/FDX  switch  is set
correctly on the distribution panel.

6.6.3  Ribbon Cables And Berg Connectors -

All of the ribbon cables and other Berg connectors in a  DMR
can be inserted two ways.  ONLY ONE OF THEM WORKS.  Here are
a few hints on getting it right the first time:

      o  The ribbon cable that goes between  the  line  unit
         and  the  microprocessor modules has no twists when
         installed correctly.  The cable is  marked  on  the
         smooth  side at each end with AA and VV.  Make sure
         that the AA edge of the cable is inserted into  the
         AA  end  of  the  module connector, and that the VV
         edge of the cable is inserted into the  VV  end  of
         the module connector.

      o  The  Ribbon  cables  that  go  from  the  M8203  to
         RS232/RS442   or   RS423  distribution  panels  are
         similarly marked.  But note that  the  Ribbed  side
         faces out.

      o  The COAX cables  that  go  to  the  Integral  Modem
         (DMR11-AC)      distribution      panel     install
         counter-intuitively;  when correctly inserted,  the
         cable  from  the connector runs toward the FRONT of
         the BA11 box and  is  squeezed  tightly  along  the
         M8203  edge.   The  plastic tab faces away from the

6.6.4  Mounting Distribution Panels -

The DMR11-AA/AB/AE (eg all but V.35) all run a ribbon  cable
from  the  M2803  to a metal distribution panel.  For proper
operation, the distribution panel must be properly  grounded
to the frame of the 2020 cabinet.  Scrape both the panel and
the cabinet rail, and use lockwashers liberally.  Also, make
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 7

sure  that  the  spot  you  pick  will  allow  clearance and
sufficient cable slack for the BA11 box to slide in/out  and
rotate  for  service,  and  that  the rear cabinet door will
close with connectors inserted into the panel.

6.6.5  Site Management Guide -

Installation of DMR11(s) on a 2020 system  is  not  complete
until  the site management guide has been updated to reflect
the new hardware and software.

The following is recommended:

      o  General Information Page
         Add an item stating that unsupported DMR11 hardware
         is installed.

      o  Bus Layout/Configuration
         Add the new device(s) to the bus  in  their  proper
         locations.  Add the BR, CSR, and vector assignments
         both here and on the label on top of the BA11 box.

      o  System and Diagnostic Software
         Insert a copy of this  document,  and  the  console
         output   of   a  complete  successful  run  of  the
         diagnostics.    Include   the   location   of   the


7.1  Availability

Diagnostics for the DMR11 are  available  to  Digital  Field
Service personnel from the DMR11 TOPS-10 developer.

7.2  Restrictions

The 2020 DMR11 diagnostics run in PDP-11 compatibility mode.
Certain  diagnostics  (noted  below) will incorrectly report
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 8

7.3  Reference Documentation

Information on operation of the  DMR11  diagnostics  can  be
found  in the DMR11 Synchronous Controller Technical Manual,
and in the Maintenance Documentation Service microfiche set.

7.4  Operation

The DMR11 diagnostics are loaded from a TOPS-10 system  pack
by  MONBTS.   They  are  provided  as PDP-10 .EXE files, and
operate under a special version of DDT11.

Five diagnostics are provided.  These are:

      o  ZDMPB0 - M8207 Static Diagnostic #1

         This  diagnostic  is  equivalent  to   the   PDP-11
         diagnostic CZDMPB0.  It performs basic tests of the
         microprocessor, and should be the first  diagnostic

      o  ZDMQB0 - M8207 Static Diagnostic #2

         This  diagnostic  is  equivalent  to   the   PDP-11
         diagnostic  CZDMQB0.  It performs extended tests of
         the  microprocessor,  and  should  be  the   second
         diagnostic run.

         You should note that the normal position of the Run
         switch  (SW7  E28) is ON, while the default for the
         diagnostic's prompt is OFF.  Tests 9,  27,  and  42
         will   fail  if  the  run  switch  is  ON  and  the
         diagnostic is not told.

         Test 31 will usually fail even with a  good  M8207;
         it  is  dependent  on CPU timing, and a KS is not a
         PDP-11.  The expected error is "ERR 100 CLOCK  TIME
         TOO FAST".

         Test 32 will also fail;  the KS  does  not  support
         remote  load  detect.  The expected errors are "ERR
         FAIL ERROR".

      o  ZDMRD0 - M8203 Static Diagnostic #1

         This  diagnostic  is  equivalent  to   the   PDP-11
         diagnostic CZDMRD0.  It performs basic tests of the
         line unit.  It assumes that the  microprocessor  is
         in  working  order,  since it is dependent on it to
         access the M8203;  the M8203 is not accessible from
         the UNIBUS.
KSDMR.BWR - Beware file for KS DMR (non-)support      Page 9

         The microprocessor Run switch (SW7  E28)  can  also
         cause test failures if set incorrectly;  however in
         this case, the default is correct.

      o  ZDMSD0 - M8203 Static Diagnostic #2

         This  diagnostic  is  equivalent  to   the   PDP-11
         diagnostic  CZDMSD0.  It performs extended tests of
         the line unit.  It should be run after ZDMRD0  runs

         This diagnostic  is  most  useful  if  you  install
         turnaround  connectors  someplace;   the diagnostic
         allows for 4 places to put  them.   One  should  be
         suitable for your site.

         The diagnostics asks  for  the  contents  of  three
         M8203  registers  that  are  derrived  from  switch
         settings.  If you change the SW  P-table,  you  can
         get  test 11 to print them for you.  Of course, you
         still get to check that what it prints  corresponds
         to what you intended to set.

      o  ZDMIC0 - DMR11 Functional Tests

         This  diagnostic  is  equivalent  to   the   PDP-11
         diagnostic CZDMIC0.  It performs functional testing
         of the DMR11 subsystem, and should be run after the
         static diagnostics.

         Test 2 will print out the  revision  level  of  the
         DMR11 CROMs.

         Test 10 will generally fail even with a good DMR11.
         It  depends  on  CPU timing.  The expected error is

7.5  Loading and Starting Diagnostics

The DMR11 diagnostics are started  in  the  same  way  as  a
monitor is.

Type Control/Backslash (\) to get the KS10> prompt.  Then BT
to  load  BOOT.   Type  DSKB:diagnostic[6,6]<CR> to load and
start DDT11.  When you get the "Input: " prompt,  enter  the
magic  string  "/UBA:3/LA36/PATCH/GO".   Typing  errors  may
cause alarming failures;  if they do, start over.  When  you
get  a  prompt  of  a  blank  line,  type 200<ESC>G to start
execution.  From this point on, the dialog is  the  same  as
that for the PDP-11 diagnostic.
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 10

For  example,  the  following  shows  loading  and  starting
        KS10>USR MOD
        BOOT V1(4)

        [Loading from DSKB:ZDMRD0[6,6]]
        DDT11 5(55)-3

        Input:  /UBA:3/LA36/PATCH/GO


           beginning execution @pc = 200

        M8203 STATIC LOGIC TESTS - PART 1 OF 2
        INIT IS M8203
        50 HZ (L) N ?
        LSI (L) N ?

        # UNITS (D) ? 1

        UNIT 0
        DEVICE CSR ADDRESS : (O) 164000 ?
        DEVICE VECTOR ADDRESS : (O) 610 ?
        M8207 RUN SWITCH (E28 SW7) - TYPE 0 IF OFF, 1 IF
        ON : (O) 1 ? 1

        CZDMR EOP   1
                0 CUMULATIVE ERRORS
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 11


8.1  Rebuild MONGEN

Building a monitor with DMR support requires that MONGEN  be
re-assembled with FTUNSUPPORTED turned on.

8.2  HDWGEN differences

When FTUNSUPPORTED is turned on,  the  dialogue  differs  in
many   places   from   the  docunentation  in  the  Software
Installation  Guide.   Only  the  DMR-specific  changes  are
discussed here.

Following the section on KDPs, a new section  on  DMR  lines

#  DMR11  Lines(0,0-8)[Number  of  DMR11  synchronous   line
     Reply with the number of DMR11s installed in your 2020.
     If a DMR is not found at run time, a message is issued,
     but the system will function without it.

The following questions are repeated for  each  DMR  in  the

 DMRn line type(ANF10,DECNET,USER,IBM):
     Reply with a one of the listed  keywords.   Your  reply
     indicates  which of the protocols listed is allowed use
     of this DMR.  USER allows you to OPEN the  DMRn  device
     and run your own protocol.  IBM has never been tried.

 DMRn switched line(Y,N)[
 Does DMRn control a switched (dial-up) line]:
     Reply "Y" or "N" as appropriate.   Switched  lines  are
     sensitive  to  DSR glitches.  Non-switched lines ignore
     them.  If you answer "N", the remaining  questions  are
     skipped, as they only apply to switched lines.

 DMRn half duplex(Y,N)[
 Does DMRn control a half duplex line]:
     Reply "Y" or "N" as appropriate.  "Y" causes the DMR to
     be  initialized in half-duplex mode.  This setting must
     be consistent at both ends of the  physical  link.   If
     you  answer  "N", the remaining question is skipped, as
     it only applies to half duplex lines.

 Is DMRn secondary(Y,N)[
 Exactly one end of the link should be a secondary station.
 Secondary status controls link startup only]:
     Half duplex DDCMP requires that  the  start  timers  on
     each  end  of  a  physical  link  differ  in  order  to
     guarantee that a  START  message  can  get  thru.   "Y"
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 12

     causes  a  three second timer to be used.  "N" causes a
     one second timer to be used.  DMC11s use a  one  second
     timer.   The timer value must be DIFFERENT at the other
     end of the physical link.

8.3  Changing The Number Of Buffers Assigned

Each DMR is assigned static buffer  space  in  COMMON.   Two
variables  in  NETPRM.MAC  determine  how  many  buffers are
available to each DMR, and how much memory is allocated.  In
general, the defaults should be adequate.  But for satellite
links, for example, you may want to increase them.

DR%NBF is  the  number  of  buffers  assigned  to  each  DMR
channel.   Each DMR has two channels (transmit and receive),
so each DMR uses 2*DR%NBF buffers.  DMRPPL is the number  of
pages  to  be  allocated  per  DMR  line.   These  pages are
permanently allocated in COMMON, and are used as DMR scratch
and buffer space.  The exact formulae for allocation of this
space may be found in NETPRM  and  DMRSER  (D8RINT.MAC).   A
reasonable  rule  of  thumb for the current software is that
increasing DR%NBF by one costs about  700(8)  words  of  DMR
buffer space.

If increasing DR%NBF will make the maximum message size  too
small, DMRPPL should be increased as well.  For small values
of DR%NBF, there is a one  for  one  correspondence  between
increasing DR%NBF and DMRPPL.

8.4  Monitor Build

The  rest  of  the  monitor  assembly  and  build   proceeds
normally.  You should assemble D8RINT.MAC in some convenient
place (after the universal files) , and  include  D8RINT.REL
in the LINK command string someplace after MONBTS and before

8.5  Considerations For Half-Duplex ANF-10 Links

Half duplex links  will  work  with  no  further  effort  to
another  KS  system.   Use  of half duplex links to a PDP-11
based ANF node requires the following (unsupported) patch:

In your C.P11 file, add the following symbol definitions for
each half duplex DMC/DMR line:

KSDMR.BWR - Beware file for KS DMR (non-)support     Page 13

LnHDX=1         ;Makes the line half duplex

LnSEC=x         ;1 makes line "secondary" (3 sec timer)

"n" is the synchronous line number of the line you  want  to
change.  Half duplex will only work with DMC/DMR lines.
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 14

File 1) BLKK:DNCDMC.P11[7,7023]         created: 1555 27-May-82
File 2) DSKP:DNCDMC.702[30,5742,TL]     created: 1540 13-Jul-82

1)5     DMCLB0: .WORD   0                       ;ADDRESS OF FIRST DMC-11 LINE
2)5             LSXHDX=B3                       ;LINE IS TO BE RUN IN HDX MODE
2)              LSXSEC=B4                       ;LINE IS A SECONDARY STATION
2)      DMCLB0: .WORD   0                       ;ADDRESS OF FIRST DMC-11 LINE
1)11            BIT     #LSXMAI,LB.STX(J)       ;IF MAINT MODE,
1)              BNE     10$                     ; THE REST IS DONE DIFFERENTLY.
2)11            BIT     #LSXHDX,LB.STX(J)       ;WANT TO RUN HDX MODE?
2)              BEQ     5$                      ;NO, NORMAL (FDX) MODE
2)              BIS     #MC.HD,R2               ;YES, SET THE BIT
2)              BIT     #LSXSEC,LB.STX(J)       ;WANT TO USE LONG START TIMER?
2)              BEQ     5$                      ;NO, WE ARE MASTER STATION
2)              BIS     #MC.SEC,R2              ;YES, SET SECONDARY BIT
2)      5$:     BIT     #LSXMAI,LB.STX(J)       ;IF MAINT MODE,
2)              BNE     10$                     ; THE REST IS DONE DIFFERENTLY.
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 15

File 1) BLKK:DNLBLK.P11[7,7023]         created: 1558 27-May-82
File 2) DSKP:DNLBLK.702[30,5742,TL]     created: 1601 15-Jul-82

1)1             .WORD   0                                       ;LB.ST2
1)      .IF NE,LBTOT
2)1             .WORD   0                                       ;LB.STX
2)      .IF NE,LBTOT
1)1     .ENDM   X
2)1     .IF DF LB.STX
2)          .IF GT DMCN
2)              .IIF NDF,L'Q'HDX,L'Q'HDX=0
2)              .IIF NE,L'Q'HDX,L'Q'HDX=1
2)              .IIF NDF,L'Q'SEC,L'Q'SEC=0
2)              .IIF NE,L'Q'SEC,L'Q'SEC=1
2)              .=.-<LB.SIZ-LB.STX>
2)              .WORD <L'Q'HDX*LSXHDX>+<L'Q'SEC*LSXSEC>
2)              .=<.-2>+<LB.SIZ-LB.STX>
2)          .ENDC
2)      .ENDC
2)      .ENDM   X
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 16

File 1) BLKK:DNDCMP.P11[7,7023]         created: 0856 07-Jul-82
File 2) DSKP:DNDCMP.702[30,5742,TL]     created: 1140 16-Jul-82

1)1             MOV     LB.SLA(J),R3            ;GET THE HARDWARE ACCESS ADDRESS FOR LINE
2)              MOV     LB.SLA(J),R3            ;GET THE HARDWARE ACCESS ADDRESS FOR LINE
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 17

File 1) BLKK:DNCNFG.P11[7,7023]         created: 0900 07-Jul-82
File 2) DSKP:DNCNFG.P11[30,5742,TL]     created: 1220 18-Jul-82

1)22    X       ZER,0   ;FIRST WORD TO ZERO ON A RESET
1)22    .IF NE,FTDUP11
2)22    X       ZER,0   ;FIRST WORD TO ZERO ON A RESET
2)      .IF NE,FTDUP11
KSDMR.BWR - Beware file for KS DMR (non-)support     Page 18


The following documents  may  be  consulted  for  additional

      o  DMR11 Synchronous Controller Technical Manual
         Describes the detailed installation and programming
         of   the   DMR11   hardware.    DEC   order  number

      o  M8203 Line Unit Technical Manual
         Describes the operation of the  line  unit  module.
         Appendix B contains the technical data for Integral
         Modem   (COAX)   cables.     DEC    order    number

      o  KS10-Based DECsystem-2020 Technical Manual
         Describes  the  operation  of  the  KS10.    Power,
         cabling,   and  Unibus  limitations  are  included.
         Also, IO programming and module  utilization.   DEC
         order number EK-0KS10-TM-002.

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The DMR:  device is programmed in a manner  similar  to  the
KDP  and  DTE  devices.   Since  these  devices  may  not be
documented  elsewhere,  this  section   will   provide   the
information necessary to program the DMR:  device.


               The DMR:  device  is  provided
               primarily   for  DEC  in-house
               use.      The      information
               presented  in  this section is
               subject  to   change   without

The DMR:  device is programmed like  any  ordinary  buffered
mode device, with the following exceptions/notes:

10.1  Dynamic DDBs

The  DMR:   device  does  not  have  a  pre-allocated   DDB.
Instead,  the  DDB is built at OPEN time.  Thus, a RESOURCES
command will not show its availibility.  DMR device  support
is  automatically  included  when  DMRs  are  included  in a

10.2  OPEN and the DMR:  device

There  is  one  DMR:   device  (DMRn:)  available  for  each
physical  DMR  built into the monitor.  A DMR:  DDB can only
be built by an OPEN UUO from a job which has POKE  (JP.POK),
JACCT,  or  [1,2]  privileges.   FILOP., and random commands
will return "no such device", as  will  OPEN  UUOs  from  an
unprivileged job.

10.3  Buffer Size

The DMR:  device will  allow  you  to  use  variable  length
buffers.   The default buffer size is constant for any given
monitor load,  but  varies  as  a  function  of  the  NETPRM
parameters DMRPPL and DR%NBF.  Thus, you should not count on
the default buffer size in any program, unless you obtain it
from a DEVSIZ UUO.
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10.4  IO Modes

Only byte mode (IO.BYT) is  allowed  to  the  DMR:   device.
Byte  mode  has a default byte size of 8 bits.  Asynchronous
IO (UU.AIO set in the OPEN block) is  supported.   The  DMR:
device  supports simultaneous input and output;  no implicit
WAIT UUOs are done by the monitor  which  would  force  half
duplex operation.

10.5  Software Interrupts

The usual software interrupts for asynchronous IO  work  for
the  DMR:   device;   Input  Done, Output Done, Input Error,
Output Error.

When DDCMP  prototocol  comes  up  on  a  line,  an  ON-LINE
interrupt  is  generated.  When DDCMP goes down, an OFF-LINE
interrupt is generated.

10.6  File Status Bits

The following File Status (GETSTS) bits are defined for  the
DMR:  device:

10.6.1  IO.IMP - Set if you attempt to use  a  DMR  that  is
assigned to another protocol (DECnet, ANF10, IBMcomm).  Also
set if a maintenance message is received while normal  DDCMP
is running.

10.6.2  IO.DTE - Set if  you  attempt  IO  to  a  line  that
doesn't  have  DDCMP  running  yet.  (Normal mode only) This
error can occur in any mode if a switched line  hasn't  been
connected  yet.   In  any  case, IO.DTE is a soft error, and
should be retried after a suitable delay.

10.6.3  IO.DER - Set if protocol on the line is (went) down.
Cleared when protocol starts.  Set when protocol goes down.
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10.6.4  IO.BKT - Set if a message is received or transmitted
that  exceeds  the maximum message size allowed.  A received
message that is too large causes the DMR to  shut  down  the

10.6.5  IO.MAI - If set, indicates that the line is  to  run
in  DDCMP  maintenance  mode.   If clear, indicates that the
line is to run in DDCMP normal mode.

10.6.6  IO.SRM (1B28) - Not currently set  by  the  monitor.
If  set,  means  that  a DDCMP START was received by the DMR
while in  maintenance  mode.   This  condition  can  not  be
dectected  by the DMR11.  But if set, this bit is treated as
an error condition.

10.6.7  IO.MRN (1B29) - Not currently set  by  the  monitor.
If  set,  means that a DDCMP MOP message was received by the
DMR while in normal  mode.   Currently,  this  condition  is
reported  by  IO.IMP.  But if set, this bit is treated as an
error condition.

10.7  Errors

Error bits are not cleared automatically by the monitor.  If
any  error  bit  is set, the monitor will refuse to initiate
further IO.  You can clear any of the error bits via OPEN or