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                      REMOTE PRINTER SPOOLER HELP FILE
                             Scott Mcclure ESI
                                  6/17/85
   
   ABSTRACT:
   	The remote printer spooler is a method to transfer print queue files
   between TOPS-20 machines using DECNET. It is activated by using the
   /DESTINATION: switch to specify the remote node where you want the file to
   be sent. (Example: PRINT filename /DESTINATION:nodename::) The file is
   then sent to the target machine and queued as a print file. All the normal
   print switches can still be used and multiple files can be sent under a
   single queue entry by using wildcards or commas between filenames.
   	The system is setup to queue transferred files as user REMOTE. To
   facilitate identification, the real user name is added to the NOTE field
   of the queue on the target machine if no other NOTE is specified.
   
   OPERATION:
   	The system consists of two parts, RMTQUE and RMTSPL. RMTQUE runs
   on the source machine while RMTSPL runs on the target machine. Data is
   transferred from RMTQUE to SPL using the DECNET 36-bit message format.
   	RMTQUE is the active portion that scans the primary master queue
   file searching for a /DESTINATION: that is remote. When found, the queue
   entry is transferred, and then the file(s) to be printed are transferred a
   page at a time. The queue entry is then removed from the local machine.
   Each transfer by RMTQUE must be acknowledged by RMTSPL or the process is
   aborted and the process attempted again on the next pass.
   	RMTSPL remains inactive until a connection is requested by RMTQUE.
   It accepts the incoming data and queues the print file when it is complete.
   Then the link is closed and SPL waits for a new connection.
	Queue entries are removed and inserted into the master queue file
   through QUASAR using IPCF messages.
   
   INSTALLATION:
   	First setup a directory called PS:<REMOTE> on each machine you want
   to print remote files on. Files transferred are placed here for printing
   and are deleted when printing is complete. In addition, since there is no
   guarantee that the username of the person making the print request will
   exist on the target machine, REMOTE is used as the user name of the printed
   file. As mentioned above, the actual user name is placed in the NOTE field
   to aid identification.
   	Next, run RMTSPL and RMTQUE on each machine. There are several ways to
   set this up, the only requirement being that the jobs have privilages
   enabled. In our system, they run as subjobs of PTYCON and are started via
   the PYTCON.ATO file. Theoretically there should be no requirement as to
   which program is started first but this has not been confirmed in practice.
   If there are already remote print files in the queue, there may be a
   problem if QUE is started and there is no SPL on the other end to receive.
   The safest bet is to start the SPL jobs first on each machine, and then
   run QUE on each machine.
   
   LIMITATIONS:
   	The system will only transfer a single page queue entry. This
   results in an upper limit of about 20 files per queue request. The system
   will only work with queue entry files of less than 513 pages. This has not
   been found to cause any problems, but should be fixed to maintain
   consistency with other DEC software.
	At this time, the system is limited to TOPS-20 machines but it should
   be possible to write a server for VAXes or other machines which can be
   connected via DECNET.
   

   KNOWN BUGS:
   	RMTSPL's DECNET server occasionally goes into aborted status. The
   program continues to run but no files are transferred. The only recovery is
   to restart RMTSPL.
	Another problem is caused by edit #1222 of QUASAR version 4.2(1236).
   This edit was intended to retain the request id number of modified print
   files. It was incomplete however and only kept the internal request number.
   The external request number was still changed. This results in RMTQUE not
   being able to cancel the queue entry after the file is transferred. The
   request remains in the queue and is sent repeatedly until the request is
   cancelled manually. DEC answered SPR #20-20479 on 2/21/85 with a patch to
   correct this problem. As we have moved to TOPS-20 version 6.0, we have not
   been able to confirm this.
   
   DEBUGGING:
   	Both programs have a debug switch to setup test versions that can be
   run while the real RMTQUE and SPL programs continue to operate. The test
   versions have their own server names and will only transfer files queued
   for /DESTINATION:TEST::. The target node name is then changed to the real
   node specified in the variable MYNODE in RMTQUE.