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                PDP-11 BOOTSTRAP FROM PDP-10

                    Date:  12-Oct-72
                    File:  BOOT11.RNO
                    Edition:  1


        This  document  reflects  the  software  as  of
        version 4(34).

        The information in this memorandum  is  subject
        to  change  without  notice  and  should not be
        construed as a commitment by Digital  Equipment

        Actual distribution of the  software  described
        in  this specification will be subject to terms
        and conditions to be announced at  some  future
        date by Digital Equipment Corporation.

        Digital  Equipment   Corporation   assumes   no
        responsibility  for  the  use or reliability of
        its software on equipment which is not supplied
        by Digital Equipment Corporation.
BOOT11                                                Page 2


BOOT11 is a bootstrap  program  designed  to  load  or  dump
programs  from  the  PDP-10  into  a PDP-11 thru the PDP-10,
PDP-11 Data Link (DL10).  The two main functions  of  BOOT11

     1.  Loading a program into PDP-11 memory from a  PDP-10
         disk file or the PDP-10 paper tape reader.

         Warning:  BOOT11 reads ONLY formatted binary PDP-11

     2.  Dumping PDP-11 memory  into  a  PDP-10  disk  file,
         creating  an  ASCII  listing of the contents of the
         PDP-11 suitable for listing on a line printer.

BOOT11 runs in USER mode under  a  DECsystem-10  timesharing
system.   It  requires a minimum of 2K of memory but expands
for IO buffers and for  the  common  memory  area  the  DL10
provides  to  the  PDP-11.   BOOT11 "locks" itself in PDP-10
memory and does IO instructions direct to the DL10 hardware.
For  this  to  work, the BOOT11 job must have privileges for
the TRPSET and LOCK functions of the timesharing system.


The program BOOT11 should normally reside in the system SYS:
area.   "R  BOOT11"  starts  the  program  which responds by


and waiting for some typed input, terminated by  a  carriage
return.   The expected input is a standard DECsystem-10 file
descriptor, followed by switches telling BOOT11 what to do:

2.1  Loading the PDP-11

    /LOAD:S         Load  the  PDP-11  from  the   specified
                    PDP-10 file and set the starting address
                    to the octal value S.

    /START:S        Load  the  PDP-11  from  the   specified
                    PDP-10  file  and start the -11 at octal
                    location S.  If :S is not  present,  the
                    default  :S is the starting address from
                    the  file  loaded.   If   the   starting
                    address from the file or from :S is odd,
                    do /LOAD and don't start.
BOOT11                                                Page 3

    /CLEAR:C        Zero  PDP-11  memory  from  0  to   C-1.
                    /CLEAR  can be used with /LOAD or /START
                    to zero -11 memory before loading.

    /IMAGE          Read the  PDP-11  load  file  in  /IMAGE
                    mode.   The  PDP-11 assemblers can write
                    binary files in  the  DECsystem-10  file
                    system   in  either  a  "packed"  or  an
                    "unpacked" format.   The  /IMAGE  switch
                    tells  BOOT11 to assume "unpacked" form.
                    Reading  from  the  paper  tape   reader
                    automatically  sets the /IMAGE switch so
                    the  file  is  read  in  the  "unpacked"

    /PORTNO:P       Do the specified  operation  for  PDP-11
                    number  P.   (PDP-11s 0-3 are on DL10#0,
                    4-7 are on DL10#1.)

/CLEAR, /IMAGE and /PORTNO may be used with /LOAD or /START.
/LOAD and /START may not be used together.

2.2  Dumping the PDP-11

    /DUMP:M         Dump PDP-11  memory  starting  at  octal
                    location  M  into  the  specified PDP-10

    /END:N          N-1 is the last address of the dump.

    /PORTNO:P       Do the specified  operation  for  PDP-11
                    number  P.   (PDP-11s 0-3 are on DL10#0,
                    4-7 are on DL10#1.)

These  three  switches  may  be  used  together.   /DUMP  is
required for dumping.

2.3  Getting Help

    /HELP           Read and type the help  text  from  file
BOOT11                                                Page 4

2.4  Defaults

Standard default values are assumed for  any  parts  of  the
file descriptor or switch values not explicitly specified:

          Item           Default value

          DEVICE:        DSK:
          FILENAME       PDPXIp
                         "p" represents  the  PDP-11  number
                         from /PORTNO:P.

          EXTENSION      .BIN for loading ,or
                         .LSD for dumping
                         (A blank extension may be  specifed
                         by  explicitly typing a dot with no
                         extension following it.)

          [PROJ,PROG]    [self], allows SFD's
          :C             First UNIBUS trap
          :M             0
          :N             First UNIBUS trap
          :S             starting address in input file
          :P             0

If no switches are specified, BOOT11 defaults to /START.  If
the  entire  input  command  is  omitted and only a carriage
return is typed, the default action is:


The simplest dump command is /D.  The defaults expand to:

          DSK:PDPXI0.LSD/DUMP:0/END:first UNIBUS trap/PORTNO:0

The switches may all be abbreviated to their first letter or


(Formatted binary is  completely  described  in  the  PDP-11
page 6-11, under "6.2.3 Absolute Loader Operation.")

BOOT11 reads only PDP-11 formatted  binary  files  .   These
files may be produced (at present) by any of five programs:

     1.  MACRO-11 (which runs on the PDP-11).   The  ".ENABL
         ABS"  pseudo instruction or the "/EN:ABS" switch in
         the command string produces the  binary  output  in
         formatted binary form.

     2.  MACX11 (which runs  on  the  PDP-10).   The  ".ABS"
BOOT11                                                     Page 5

         pseudo  instruction  gives formatted binary output.
         The output may be directed to the file system or to
         paper  tape.   The  /I switch in the command string
         gives  "unpacked"  formatted  binary.   The  MACX11
         assembler  is  not  supported  by Digital now;  the
         MACY11 assembler is the supported PDP-11  assembler
         running on the PDP-10.

     3.  MACY11 (which runs on  the  PDP-10).   The  ".ENABL
         ABS"   pseudo   instruction,   the   ".ABS"  pseudo
         instruction  (which  is  not  preferred),  and  the
         "/EN:ABS"  switch in the command string may be used
         to give formatted binary output.   The  /I  command
         string  switch  gives  "unpacked"  binary output as
         opposed to "packed"  output  which  is  the  normal

     4.  LINK (running  on  the  PDP-11)  loads  relocatable
         binary files and produces formatted binary output.

     5.  LNKX11, the  PDP-10  executable  version  of  LINK,
         reads  relocatable  binary files for the PDP-11 and
         produces formatted binary output.  The  /I  command
         string  switch  gives  "unpacked"  binary output as
         opposed to "packed"  output  which  is  the  normal

There are two versions of formatted binary  output  produced
by  MACX11, MACY11 and LNKX11:  "packed" and "unpacked." The
"packed" variation is the normal  default  and  consists  of
four 8-bit frames of formatted binary output packed into one
PDP-10 word.  (The packed binary files are very conveniently
stored  in the PDP-10 file system.) The packed format cannot
be punched onto paper tape directly with any current program
other  than  the  paper  tape spooler.  QUEUE's /TAPE:ELEVEN
switch tells the spooler to unpack the packed data  for  the
paper tape punch.

The "unpacked" variation consists of  one  8-bit  frame  per
PDP-10  word  and is produced by using the /I command string
switch.  The "unpacked" variation is the  required  form  of
the  binary  data  if  it  is  to be punched onto paper tape
either directly or with PIP.   (If  PIP  is  used  PIP's  /I
switch is required.)

BOOT11 reads either "packed" or "unpacked" binary data.  For
"unpacked"  data,  the /IMAGE switch is required.  If BOOT11
reads an "unpacked" file from the file  system  without  the
/IMAGE  switch,  it  detects  an  error and prints a warning
message, sets the  /IMAGE  switch  and  starts  the  loading
operation  over  again.   When  reading  from the paper tape
reader, BOOT11 always sets the /IMAGE switch itself,  so  no
/IMAGE switch is required in the command string.

PDP-11 paper tapes in formatted binary may be transferred to
BOOT11                                                     Page 6

the  -10  file  system  for  future use.  The tape should be
placed in the PDP-10 paper tape reader with the read head in
the  blank  tape  area  after the punched title, if any, and
before the binary data.  (The start of the  binary  data  is
indicated  by  a  frame of 1 followed by a frame of 0.) PIP,
with the /I switch, copies the tape into  the  file  system.
Files tranferred this way are in the "unpacked" format.  Use
the /IMAGE switch in BOOT11.


BOOT11 uses the DL10 hardware to load, clear,  or  dump  the
PDP-11  memory  and  to  start  or stop the PDP-11 processor

The PDP-11/15 console panel (KY11C) has  a  "remote  control
cable"  that  plugs  into  the DL10.  This cable enables the
DL10 to toggle the PDP-11 HALT and START switches  remotely,
to  examine  the  state of PDP-11 power, and to determine if
the PDP-11 is running or is stopped.  When the  DL10  starts
the  PDP-11,  the  DL10  sends  the  starting address to the
PDP-11 over the Unibus.  The starting address (100002) is in
an  area  of  -11  memory  to  which  the  DL10 responds and
supplies data from PDP-10 memory cores.  In effect, a PDP-11
program  is  started  which  executes  out of PDP-10 memory.
This PDP-11 program is part of  BOOT11  and  has  the  major
function  of  transferring  data from the -10 to the -11 for
loading and clearing operations, or from the -11 to the  -10
for  the  dumping operation.  BOOT11 either supplies data to
the -11 from the formatted binary input file, or  takes  the
PDP-11  core  image  and writes an -11 dump file on some -10

Various things can go wrong with  these  operations.   Error
messages   are   generated   for   any  of  a  multitude  of
malfunctions.   These  messages  are  listed  in  the   next


    " PDP-11 loading
               The PDP-11 is being loaded with the formatted
               binary input file data.

    " PDP-11 loaded
    " PDP-11 started
               The loading is complete and the PDP-11 is now
               executing code in its own memory.

    " PDP-11 dumping
               The PDP-11 memory  is  being  dumped  into  a
BOOT11                                                     Page 7

               PDP-10 file.

    " PDP-11 dumped
    " Clearing PDP-11
               The -11 memory is being zeroed.

    % File zero byte count--trying again in /IMAGE mode
               This  warning  message  indicates  that   the
               formatted   binary   input  file  is  not  in
               "packed"  form   and   probably   is   really
               "unpacked"  data.   BOOT11  sets  the  /IMAGE
               switch and tries to load the  file  again  in
               the "unpacked" format.

5.1  Command String Error Messages

    ? Can't /CLEAR and /DUMP at the same time
    ? Can't /LOAD and /DUMP at the same time
    ? Can't do both /LOAD and /START
    ? Port number must be 0-7
    ? Ambiguous switch--type /H for help
    ? Unknown switch--type /H for help
    ? Command error--type /H for help

5.2  Formatted Binary File Input Error Messages

    ? Can't OPEN the input device
               The input device does not exist or is in use.
               (Also refer to the DECsystem-10 MONITOR CALLS

    ? LOOKUP failed
               The  input  file  is  not  found,   is   read
               protected,  or  the  input  device doesn't do
               input.   (Also  refer  to  the   DECsystem-10
               MONITOR CALLS Manual.)

    ? EOF at start of file group
               This and the next  five  EOF  failures  occur
               when the end of the input file is reached and
               more data is required for the binary format.

    ? EOF after file constant 1
    ? EOF during data in file group
    ? EOF found when looking for checksum
    ? EOF during first byte of a word
    ? EOF during second byte of a word
    ? Input file read error
    ? File group has junk instead of constant 0
               This and the next five errors  indicate  that
               the  input  binary file is not in the correct
BOOT11                                                     Page 8

               data format.

    ? File group has junk instead of constant 1
    ? File group byte count less than 6
    ? Junk bits in input file
    ? Junk in input file--may not be /IMAGE mode
               Reading a "packed" formatted input file  with
               the  /IMAGE switch will normally produce this
               message.   Try  again  without   the   /IMAGE

    ? Junk after start group
               Not enough zero 8-bit frames are on  the  end
               of  the  file.  A paper tape torn to close to
               the end of the binary  data  will  give  this
               message.   Leave  at least ten zero frames on
               the tape end (at least one inch or 2.5cm).

    ? Checksum failure
               The data check in the binary  file  is  wrong
               for some unknown reason.

5.3  Dump File Output Error Messages

    ? Can't OPEN the output device
               The output device does not  exist  or  is  in
               use.  (Also refer to the DECsystem-10 MONITOR
               CALLS Manual.)

    ? ENTER failed
               The output file is being modified or the file
               or  the UFD is write protected.  Also see the
               DECsystem-10 MONITOR CALLS manual.

    ? Output device error
               Insufficient room exists on the output device
               for   the   dump   file.    (Refer   to   the
               DECsystem-10 MONITOR CALLS Manual.)

5.4  Miscellaneous Failure Messages

    ? Insufficient core
               BOOT11 needs more memory  and  can't  get  it
               from the Monitor.  Call your DEC salesman.

    ? TRPSET failed
               The job does  not  have  the  privileges  for
               TRPSET,  or  TRPSET  is  not  built into this
               version of the Monitor.  (See  your  friendly
               system manager.)
BOOT11                                                     Page 9

    ? LOCK failed
               The job does not have LOCK  priveleges,  LOCK
               is not built into the Monitor, doing the LOCK
               UUO would  exclude  from  memory  an  already
               existent  job, or locking the job would cause
               the amount of unlocked memory to be less than
               CORMIN.   In  this  last  case,  persuade the
               operator to  "SET  CORMIN  n"  to  a  smaller

    ? NXM in -11 memory
               The PDP-11 had  a  bus  trap  failure.   This
               usually  results  from trying to load or dump
               more PDP-11 memory than  exists.   (Your  DEC
               salesman can arrange for more PDP-11 memory.)

    ? NXM or parity error in -10 memory
               This  shouldn't   happen.    The   DL10   has
               referenced  non-existent PDP-10 memory or has
               discovered a memory problem.  Notify  DEC  of
               any parity errors.

    ? PDP-11 won't start--check HALT switch
               The DL10 can't start the  PDP-11  within  one
               second.   The usual reason is the PDP-11 HALT
               switch is depressed.  Check the  HALT  switch
               and try again.

    ? PDP-11 won't stop
               The DL10 can't stop the PDP-11.  The  problem
               is  likely the control cable from the DL10 to
               the PDP-11.

    ? PDP-11 absent or power off
               Either a DL10 is not connected to the PDP-10,
               the  PDP-11  or the DL10 has its power turned
               off, or there is not a DL10.

    ? PDP-11 took too long in transfer loop
               BOOT11 has counters in each wait loop for the
               PDP-11.   The  counter counted out one second
               before the  PDP-11  completed  a  step  in  a
               PDP-10/PDP-11  transfer  operation for /LOAD,
               /DUMP, or /CLEAR.

[End of BOOT11.RNO]