Christopher McNabb wrote: Not sure how much help this will be, but here is a program I used to create TAP files on RSTS and VMS systems. This particular copy was used on a VAX system, so you will need to adjust the value assigned to MAX_RECORD% for the smaller memory available on a PDP-11 (8192 should work well). You may also need to strip down the "open" statement for the tape drive (lose organization, recordtype and access; but leave the recordsize), but you might need them if you compile with Basic+2. Code is ugly, but it worked. Images created were usable with simh. It might at least give you a start at reversing the process. 1 ! ! Program to read a tape into simh format file ! ! Ugly and rough, but it works. ! Anything unexpected will cause it to crash. ! ! You must first "mount mka500:/for/blo=65000" before ! running this ! ! 08/16/2002 - Kevin Handy ! Fixed it so it actualy works ! 100 TAPE.CH% = 7% LINPUT "Tape device <MKA500:> ", TAPE_DEVICE$ TAPE_DEVICE$ = "MKA500:" IF TAPE_DEVICE$ = "" ! ! Make this smaller for RSTS, else it will run out of memory ! MAX_RECORD% = 50240% OPEN TAPE_DEVICE$ for input AS FILE TAPE.CH%, & ORGANIZATION SEQUENTIAL, & RECORDTYPE NONE, & RECORDSIZE MAX_RECORD%, & ACCESS READ V% = MAGTAPE(3%, 0%, tape.CH%) ! Rewind tape 110 FILE.CH% = 8% LINPUT "Save into <tape.tape> ", FILE_NAME$ FILE_NAME$ = "TAPE.TAPE" IF FILE_NAME$ = "" ! ! Lose everything from ORGANIZATION on for RSTS, which doesn't ! need it. ! OPEN FILE_NAME$ FOR OUTPUT AS FILE FILE.CH%, & ORGANIZATION SEQUENTIAL fixed, & RECORDTYPE NONE, & RECORDSIZE 512% EOF% = 0% 200 WHEN ERROR IN GET #TAPE.CH% RCT% = recount USE IF ERR = 11% OR ERR=252% THEN CONTINUE WriteEOF END IF PRINT "Unhandled error"; err; " "; ert$(err) stop END WHEN EOF% = 0% print "!";rct%; print RCT% if ccpos(0%) >= 50% 250 FIELD #TAPE.CH%, RCT% AS TBUFFER$ BUFFER$ = BUFFER$ + & CHR$(RCT% AND 255%) + & CHR$(RCT% / 256% AND 255%) + & CHR$(RCT% / (256% * 256%) AND 255%) + & CHR$(RCT% / (256% * 256%* 256%) AND 255%) + & & TBUFFER$ + & & CHR$(RCT% AND 255%) + & CHR$(RCT% / 256% AND 255%) + & CHR$(RCT% / (256% * 256%) AND 255%) + & CHR$(RCT% / (256% * 256%* 256%) AND 255%) GOSUB WriteBlocks GOTO 200 WriteEof: IF EOF% = 0% THEN ! ! First EOF ! RCT% = 0% GOSUB WriteLength EOF% = 1% ELSE ! ! Second EOF ! RCT% = 0% GOSUB WriteLength GOSUB WriteLength GOTO ExitProgram END IF GOTO 200 WriteLength: 500 BUFFER$ = BUFFER$ + & CHR$(RCT% AND 255%) + & CHR$(RCT% / 256% AND 255%) + & CHR$(RCT% / (256% * 256%) AND 255%) + & CHR$(RCT% / (256% * 256%* 256%) AND 255%) GOSUB WriteBlocks RETURN WriteBlocks: 600 WHILE LEN(BUFFER$) >= 512% FIELD #FILE.CH%, 512% AS XBUFFER$ LSET XBUFFER$ = BUFFER$ PUT #FILE.CH% BUFFER$ = RIGHT(BUFFER$, 513%) NEXT RETURN ExitProgram: 10000 GOSUB WriteBlocks IF BUFFER$ <> "" THEN FIELD #FILE.CH%, 512% AS XBUFFER$ LSET XBUFFER$ = BUFFER$ PUT #FILE.CH% END IF CLOSE FILE.CH% CLOSE TAPE.CH% 32767 END