OS/8 ENCODING PROGRAM
PROGRAM TO ENCODE OS/8 FILES INTO "PRINTABLE" ASCII FORMAT ("ENCODE").
DISTRIBUTED BY CUCCA AS "K12ENC.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 ENCODE INVOKE PROGRAM
*OUTPUT<INPUT PASS ONE INPUT AND ONE OUTPUT FILE ONLY (WITH <CR>)
*OUTPUT<DEV:=NNNN/I **** SPECIAL IMAGE TRANSFER MODE **** INPUT IS RECORD
0000-[NNNN-1] ON DEVICE DEV:. THE =NNNN VALUE MUST BE
STATED PRECISELY TO TRANSFER THE REQUISITE AMOUNT OF
THE DEVICE AS REQUIRED. THE VALUE IS GENERALLY THE
TOTAL LENGTH OF THE DEVICE, BUT COULD BE LESS AS
NECESSARY; LARGER VALUES WILL GENERALLY FAIL. THIS
MODE SHOULD ONLY BE USED TO EFFECT TRANSFER OF
COMPLETE DEVICE IMAGES WHERE THE NORMAL OS/8 FILE
STRUCTURE IS UNSUITABLE. IN THIS MODE, THE OS/8 FILE
(POSSIBLY PRESENT) ON THE DEVICE IS IGNORED. ****
NOTE **** THIS METHOD VIOLATES ALL OS/8 DEVICE
STRUCTURE AND IS MEANT FOR TRANSFER OF COMPLETE DEVICE
IMAGES ONLY; USE WITH CARE!
*OUTPUT<DEV:=NNNN/I/1 **** SPECIAL IMAGE TRANSFER MODE **** SAME AS REGULAR
IMAGE MODE EXCEPT ONLY THE FIRST HALF OF THE DATA IS
USED. THE DECODER MUST BE GIVEN THE EQUIVALENT
PARAMETERS TO TRANSFER THE FIRST HALF.
*OUTPUT<DEV:=NNNN/I/2 **** SPECIAL IMAGE TRANSFER MODE **** SAME AS REGULAR
IMAGE MODE EXCEPT ONLY THE SECOND HALF OF THE DATA IS
USED. NOTE THAT THERE MUST BE TWO FILES CREATED, ONE
USING /I/1 AND THE OTHER USING /I/2 TO COMPLETELY
TRANSFER A DEVICE IMAGE UNLESS /I IS USED ALONE!
*OUTPUT<INPUT$ PASS ONE INPUT AND ONE OUTPUT FILE ONLY (WITH <ESC>)
. PROGRAM EXITS NORMALLY
INPUT FILE ASSUMES .SV EXTENSION; THERE IS NO ASSUMED OUTPUT EXTENSION. IF
IMAGE MODE IS USED, THERE IS NO INPUT FILE SPECIFICATION; ONLY A DEVICE IS
GIVEN ALONG WITH A LENGTH AND THE MANDATORY /I SWITCH.
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 <ESC>
CHARACTER.
THIS PROGRAM SUPPORTS A SUBSET OF THE ASCII FILE ENCODING SCHEME DEVELOPED BY
CHARLES LASNER AND FRANK DA CRUZ. THE SCHEME USED IS FIVE-BIT ENCODING WITH
COMPRESSION, (AS OPPOSED TO SIX-BIT WITHOUT COMPRESSION AS USED IN PRIOR
VERSIONS).
RESTRICTIONS:
A) NO SUPPORT FOR MULTIPLE DECODABLE FILES PER ENCODED FILE.
B) CREATES ENCODED PDP-8 60-BIT CHECKSUM AT END OF FILE.
C) CUSTOMIZED (REMARK) COMMANDS MUST BE SEPARATELY ADDED BY THE USER.
D) THE FILENAME IN THE (FILE ) AND (END ) COMMANDS WILL BE IDENTICAL TO
THE ACTUAL INVOKED INPUT FILE. THE USER MUST SEPARATELY MODIFY THESE
COMMANDS WHEN EXPORTING THE ENCODED FILE TO A SYSTEM WITH DIFFERENT
NAMING CONVENTIONS.
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.
ASSEMBLY INSTRUCTIONS.
IT IS ASSUMED THE SOURCE FILE K12ENC.PAL HAS BEEN MOVED AND RENAMED TO
DSK:ENCODE.PA.
.PAL ENCODE<ENCODE/E/F ASSEMBLE SOURCE PROGRAM
.LOAD ENCODE LOAD THE BINARY FILE
.SAVE DEV ENCODE=2001 SAVE THE CORE-IMAGE FILE
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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