Archiving DECtapes
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DECtape is a block-oriented magnetic media format more akin to the floppy disk than 9 track tape. There are four prevailing formats: LINC, 18, 16 and 12 bit. For years DEC distributed diagnostics, system distributions and sources on DECtape and our library consists of somewhere between 500 ~ 800 tapes.


It is possible to use an OS/8 utility called PIP10 on the PDP-8 to work with an 18-bit format tape on a 12-bit machine, but we only need to use the PDP-8/e to create an image of the tape. We can do this using a stand alone DECtape dump utility written by Kyle Owen (and modified by Josh Dersch at Living Computers) which runs on a laptop and communicates with the PDP-8/e via the main serial terminal. A complete image of a tape yields 592896 8-bit bytes and takes about 5 minutes to produce. These tape images are currently being stored on the SDF anonymous FTP server. The tendmp utility written by Lars Brinkhoff can be used to list the directory and extract files from the tape.
Label: 10NOV4
1. DTAMON SAV 8 1973-04-11
2. KICPU CMD 2 1973-04-09
3. DBKAA SAV 19 1972-03-16
4. DBKAB SAV 21 1972-03-16
5. DBKAC SAV 15 1972-03-16
6. DBKAD SAV 16 1972-03-16
7. DBKAE SAV 12 1972-03-16
8. DBKAF SAV 16 1972-03-16
9. DBKAG SAV 7 1972-03-16
10. DBKAH SAV 38 1972-03-16
11. DBKAI SAV 48 1974-12-13
12. DBKAJ SAV 36 1973-04-09
13. DBKAK SAV 58 1972-03-16
14. DBKAL SAV 61 1972-03-16
15. DBKAM SAV 41 1972-03-16
16. DKISPL SAV 4 1973-03-16
Free blocks: 172

THIS TAPE CONTAINS SOURCES AND SAVE FILES OF DOCTOR AND
ELIZA, ADAPTED FOR THE STANFORD A.I. LISP 1.6 SYSTEM AND COMPILED
TO RUN UP TO SIX TIMES FASTER THAN PREVIOUS VERSIONS.
(A FEW BUGS HAVE ALSO BEEN FIXED.)
FILES ON THE TAPE:
DOCPGM.LSP SOURCE OF THE LISP PROGRAM
DOCPGM.LAP COMPILED (LAP) CODE OF THE ABOVE PROGRAM
DOCTOR.RLS THE "RULES" FOR DOCTOR
ELIZA.RLS THE "RULES" FOR ELIZA
SPEC SPECIAL VARIABLE DECLARATIONS TO COMPILE DOCPGM
DOCTOR.SAV SAVE FILE OF DOCTOR
ELIZA.SAV SAVE FILE OF ELIZA
DUMP EXPRS FOR DUMPING DOCTOR CORE IMAGES
DOCTOR.TXT THIS BLURB
PROCEDURE FOR CREATING A NEW DOCTOR OR ELIZA (RULES FOR DOCTOR
ONLY ARE GIVEN, ELIZA CALLS FOR THE OBVIOUS CHANGES)
1. COPY THIS DTA TO DISK
2. IF YOU DO NOT WISH TO RECOMPILE DOCPGM GO TO STEP 5.
3. COMBINE SPEC AND DOCPGM.LSP USING PIP:
.R PIP
*DOCPGM_SPEC,DOCPGM.LSP
*
4. RUN THE LISP COMPILER AND COMPILE DOCPGM
^C
.R COMPLR
*(COMPL DOCPGM)
<RANDOM OUTPUT>
*^C
.
5. GET LISP SET UP
.R LISP 16
ALLOC Y
FULL WDS=640
BIN.PROG.SP=1540
SPEC.PDL=200
REG. PDL=300
HASH=37
AUXILIARY FILES?Y
SMILE?
ALVINE?
TRACE?
LAP?Y
DECIMAL?N
*
6. READ IN THE COMPILED LAP CODE
*(INC(INPUT DSK: (DOCPGM.LAP$
<RANDOM OUTPUT>
*
7. READ IN THE RULES
*(INC(INPUT DSK: (DOCTOR.RLS$
<MORE RANDOM OUTPUT>
*
8. CLEAN UP CRUD IN THE CORE IMAGE
*(EXCISE)
*(NOUUO NIL)
*(REMOB /%DEFIN DE DF DM PUTSYM GETSYM)
*(GC)
*^C
.
9. JFCL THE "*". THE ADDRESSES MAY CHANGE DEPENDING ON VERSION
OF LISP.
.E 6457
006457/ 051040 006455 .D 255000 0 6457
.
10. SAVE THE PROGRAM
.SAVE DSK DOCTOR
JOB SAVED
^C
.
/ TONY LAUCK 30-MAR-70
Tape imaging will be live streamed from time to time so please follow https://twitch.tv/sdfpubnix to get notified when we go live. More to come!