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TOPS20 Change Order Number 4.2497

Written by: SCHMITT		27-Sep-79 17:49:38

Edit checked: NO			   Document: NO
  TCO Tested: NO		Maintenance Release: NO
Hardware-related: NO

Program: PTYCON

Related TCO's:
Related SPR's: 


Problem: When perfoming the GET fuction, sometimes a ghost
<LF> appears in the PTY's input buffer.

Diagnosis: When PTYCON checks to see whether an <ESC> character
is in its input buffer, it performs a BIN JSYS and a BKJFN JSYS
to check out the character.  If the input file had been at EOF,
the BKJFN would have moved the file pointer before the last 
character in the file, (which many times is a <LF>)

Solution: Insert an ERJMP after the BIN in question which will
bypass the BKJFN

TOPS20 Change Order Number 4.2522

Written by: SCHMITT		 9-Oct-79 15:59:44

Edit checked: NO			   Document: NO
  TCO Tested: YES		Maintenance Release: NO
Hardware-related: NO

Program: PTYCON

Related TCO's:
Related SPR's: 


Problem: No known problem but code could cause some

Diagnosis: PTYCON releases a JFN used by the GET JSYS.  This
should not be done because the GET JSYS changes the owner
of the file from the process that issued the GET to the
process into which the file is mapped.  When the latter
process is killed, the JFN is released.  

Because a program can not be sure that GET has or has not released
the JFN, the program should not attempt to release the JFN itself
or attempt to use the JFN again.  At the time that a program
tried to erroneously release the JFN, the JFN might have been 
associated with a file other than the file the GET was performed on.

Solution: Change the order in which the fork is created and a JFN
acquired on the new EXEC at PUSHE.  This is so that there will be
no need to push or pop the JFN on the stack (makes error recovery 
easier).  At PUSHE1+3, remove the POP, RLJFN, and JFCL.  This isn't
needed because the JFN was never put on the stack and the RLJFN
should not be performed anyway.

At NOEXEC+1 insert code to get back the process handle of the inferior
fork and kill it.

TOPS20 Change Order Number 4.2546

Written by: ENGEL		24-Oct-79 15:40:28

Edit checked: NO			   Document: NO
  TCO Tested: NO		Maintenance Release: NO
Hardware-related: NO

Program: PTYCON

Related TCO's:
Related SPR's: 


Problem: PTYCON OVERUNS TH PTY'S

Diagnosis: PYTCON DOES NOT KNOW THAT THE ^G'S BEING SENT BACK
ARE REALLY "BUFFER FULL" MESSAGES.

Solution: TTYSRV WAS CHANGED TO PROVIDE AN ERROR WHEN OUTPUT IS DONE
ON A PTY WITH A FULL BUFFER.  HAVE PTYCON DO A DIBE WHEN THE BUFFER IS FULL.