According to Scott Lurndal <
slp53@pacbell.net>: >
http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp10/KC10_Jupiter/Jupiter_CIS_Instructions_Oct80.pdf
Interesting quote that indicates the direction they were looking:
"Many of the instructions in this specification could only
be used by COBOL if 9-bit ASCII were supported. There is currently
no plan for COBOL to support 9-bit ASCII".
"The following goals were taken into consideration when deriving an
address scheme for addressing 9-bit byte strings:"
Fundamentally, 36-bit words ended up being a dead-end.
Interesting document. It added half-hearted 9 bit byte addressing to the PDP-10, intended for COBOL string processing and decimal arithmetic.
Except that the PDP-10's existing byte instructions let you use any byte
size you wanted, and everyone used 7-bit bytes for ASCII strings. It would have been straightforward but very tedious to add 9 bit byte strings to
the COBOL compiler since they'd need ways to say which text data was in
which format and convert as needed. Who knows what they'd have done for
data files.
36 bit word machines had a good run starting in the mid 1950s but once
S/360 came out with 8 bit bytes and power of two addressing for larger
data, all of the other addressing models were doomed.
--
Regards,
John Levine,
johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail.
https://jl.ly
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