OS/8 BOO ENCODING PROGRAM
PROGRAM TO ENCODE ANY TYPE OF OS/8 FILE INTO "PRINTABLE" ASCII (".BOO")
FORMAT. THIS IS A COMMON DISTRIBUTION FORMAT FOR MANY COLUMBIA KERMIT FILES
AND IS AN ALTERNATIVE TO ENCODE FORMAT FOR PDP-8 AND DECMATE USERS.
DISTRIBUTED BY CUCCA AS "K12ENB.PAL" AS PART OF THE CUCCA KERMIT-12 PACKAGE.
WRITTEN BY:
CHARLES LASNER (CJL)
CLA SYSTEMS
72-55 METROPOLITAN AVENUE
MIDDLE VILLAGE, NEW YORK 11379-2107
(718) 894-6499
USAGE:
.RUN DEV ENBOO INVOKE PROGRAM
*OUTPUT)
*OUTPUT)
. PROGRAM EXITS NORMALLY
INPUT FILE ASSUMES .SV EXTENSION; THERE IS NO ASSUMED OUTPUT EXTENSION.
PROGRAM EXIT IS THE NORMAL OS/8 METHOD OF EITHER PRESSING <^C> ON THE CONSOLE
KEYBOARD DURING THE COMMAND, OR ENDING THE COMMAND INPUT LINE WITH AN
CHARACTER.
THIS PROGRAM SUPPORTS THE .BOO FORMAT FOR FILE ENCODING WHICH IS POPULAR IN
OTHER SYSTEMS. THIS VERSION IMPLEMENTS THE FILE LENGTH PROTECTION SCHEME
DEVELOPED BY CHARLES LASNER TO ENSURE PRECISE FILE LENGTH.
MANY .BOO PROGRAMS HAVE PROBLEMS MAINTAINING PRECISE FILE LENGTH. THE ACTUAL
LENGTH MAY BE IMPRECISELY STATED BY ONE OR TWO BYTES DUE TO AN INHERENT
WEAKNESS IN THE ORIGINAL .BOO ENCODING FORMAT DESIGN. THIS IMPLEMENTATION
APPENDS CORRECTION BYTES AS NECESSARY TO THE BASIC .BOO FILE TO ENSURE PROPER
DECODING BY PROGRAMS COMPATIBLE WITH THIS EXTENSION.
FILES CREATED BY THIS PROGRAM MAY BE USED WITH EARLIER .BOO DECODERS; THE
RESULTANT FILES MAY INACCURATELY RECREATE THE ORIGINAL FILES BY AS MUCH AS TWO
EXTRANEOUS TRAILING BYTES. THERE WILL BE NO PROBLEMS (BEYOND THE LENGTH
ANOMALY) AS LONG AS THE DECODERS IMPLEMENT ZERO-LENGTH COMPRESSION FIELDS AS
NO OPERATION. IT IS POSSIBLE THAT CERTAIN DECODERS COULD ERRONEOUSLY APPEND
MASSIVE QUANTITIES OF ZEROES ONTO THE END OF THE DECODED FILES, BUT THIS
ACTION WOULD CERTAINLY BE CAUSED BY DEFECTIVE PROGRAM CODE WITHIN THE DECODER.
(ALTHOUGH NOT LIKELY SEEN BEFORE ENCOUNTERING FILES WITH LENGTH CORRECTION
BYTES, THIS WOULD BE A LATENT BUG IN THESE DECODING PROGRAMS. UPDATED
VERSIONS SHOULD BE SOUGHT IF THIS PROBLEM SURFACES.)
ERROR MESSAGES.
ERROR MESSAGES ARE ONE OF TWO VARIETIES: COMMAND DECODER MESSAGES AND USER
(PROGRAM-SIGNALLED) MESSAGES.
COMMAND DECODER MESSAGES ARE NON-FATAL AND MERELY REQUIRE RETYPING THE
COMMAND. ATTEMPTING TO USE MORE THAN ONE OUTPUT FILE WILL YIELD THE COMMAND
DECODER MESSAGE "TOO MANY FILES" AND CAUSE A REPEAT OF THE COMMAND DECODER
PROMPT REQUIRING USER INPUT. THE USER IS DIRECTED TO OTHER DOCUMENTATION OF
THE "SPECIAL" MODE OF THE COMMAND DECODER, AS THAT IS THE ONLY MODE USED BY
THIS UTILITY PROGRAM.
ANY USER MESSAGE PRINTED IS A FATAL ERROR MESSAGE CAUSED BY A PROBLEM BEYOND
THE SCOPE OF THE COMMAND DECODER. ALL USER MESSAGES ARE THE STANDARD OS/8
"USER" ERROR MESSAGES OF THE FORM: "USER ERROR X AT AAAAA", WHERE X IS THE
ERROR NUMBER AND AAAAA IS THE PROGRAM ADDRESS WHERE THE ERROR WAS DETECTED.
THE FOLLOWING USER ERRORS ARE DEFINED:
ERROR NUMBER PROBABLE CAUSE
0 NO OUTPUT FILE.
1 INPUT FILE ERROR (CAN'T FIND INPUT FILE) OR NO INPUT
FILE SPECIFIED OR TOO MANY INPUT FILES SPECIFIED.
2 ILLEGAL OUTPUT FILE NAME (WILD CARDS NOT ALLOWED).
3 NO OUTPUT FILE NAME (DEVICE ONLY IS NOT ALLOWED).
4 ERROR WHILE FETCHING FILE HANDLER.
5 ERROR WHILE ATTEMPTING TO ENTER OUTPUT FILE.
6 OUTPUT FILE LARGER THAN AVAILABLE FILE SPACE.
7 ERROR WHILE CLOSING THE OUTPUT FILE.
8 I/O ERROR WHILE ENCODING FILE DATA.
9 OUTPUT ERROR WHILE ENCODING FILE DATA.
ASSEMBLY INSTRUCTIONS.
IT IS ASSUMED THE SOURCE FILE K12ENB.PAL HAS BEEN MOVED AND RENAMED TO
DSK:ENBOO.PA.
.PAL ENBOO
Feel free to contact me, David Gesswein djg@pdp8online.com
with any questions, comments on the web site, or if you have related equipment,
documentation, software etc. you are willing to part with. I am
interested in anything PDP-8
related, computers, peripherals used with them, DEC or third party, or
documentation.
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