[TUHS] Re: origin of null-terminated strings

MACRO10 (the DEC PDP-10 assembler) had the ASCIZ directive, I don't see it in the May 1964 MACRO6 (PDP-6 assembler) document at: http://bitsavers.trailing-edge.com/pdf/dec/pdp6/F-64MAS_MACRO6_Assembly_Pro… Nor the February 1965 version: http://bitsavers.trailing-edge.com/pdf/dec/pdp6/DEC-6-0-TP-MAC-LM-FP-ACT01_… But it does appear in the May 1965 MACRO-6 manual: http://bitsavers.trailing-edge.com/pdf/dec/pdp6/DEC-6-0-TP-MAC-LM-FP_ACT02_… Which has the fullly trifuricated character packings: ASCII/ASCIZ: 7 bit bytes, with the low order bit left over (set at the start of lines in files to indicate a Line Sequence Number metadata for line number based editors) SIXBIT "6-bit ASCII" -- ASCII characters 040 thru 0137 stored as 00 thru 077 in six six bit bytes RADIX50 6 characters from a 40 (050) character character set (plus four flag bits) used to store symbol tables https://en.wikipedia.org/wiki/DEC_RADIX_50#36-bit_systems And ASCIZ is used in listings of the PDP-6 "T.S. Executive" version 1.4 dated 8-18-65: http://bitsavers.trailing-edge.com/pdf/dec/pdp6/tsExec1.4/COMCON.pdf COMCON is "COMmand CONtrol" -- the top level command interpreter built into the monitor (the file name was retained into the later days of TOPS-10), and messages output to the user use ASCIZ directives. And to tie the thread back (closer) to the list subject, the "sub title" headers in the above assembler listing file are "T. HASTINGS 8-2-65" (who I believe is Tom Hastings), which also appears in many other files, including the job scheduler: http://bitsavers.trailing-edge.com/pdf/dec/pdp6/tsExec1.4/CLKCSS.pdf *AND* T. Hastings also appears as an author of the CTSS scheduler: https://softwarehistory.csse.rose-hulman.edu/index.php/ctss-scheduler/ (in the "Full Code" section): :R******TIME SHARING SCHEDULING ALGORITHM*********** :R T. Hastings and R. Daley :R Minor Modifications by G. Schroeder when NEW :R I/O Package Installed....Summer, 1965