Univac 1100/2200 Byte Size (Re: The joy of FORTRAN)

On 2025-02-26, Peter Flass <peter_flass@yahoo.com> wrote:

Multics used 8-bit bytes on a 36-bit Honeywell 6000. The developers tried
to discourage the use of 9-bit bytes - I was told that “nothing” used them,
but I found out WordPerfect used them for metacharacters.

On 2025-02-27, Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:

I never got to work on Univac's 36-bit systems, but I heard that
they could do 9-bit stuff.

The Univac 1100's that I spent 5 years with (1970-1975) were 36-bit
machines inspired by IBM's 700/7000 family. They were performing well
for
  - Scientific computation, where their 36-bit floating point was mostly
    good enough, so you did not need double precision
  - Real-Time applications, where they had low latency and short
    pathlengths for interrupts as well as good OS support for real-time
    responsiveness, a legacy of their 30-bit predecessors
  - transaction processing, where their FastRand drums were available
    early in the market

The CPU register/memory instructions had fields to select partial words:
    LA,H1 R1,DATA
There were
    HalfWords    H1, H2
    QuarterWords Q1, Q2, Q3, Q4
    Sixths       S1, S2, S3, S4, S5, S6

Originally, all text fields were in 6-bit characters called FIELDATA.
Later, to accommodate lowercase, it became reasonably common to put
7-bit ASCII into quarter-words (9 bits).

When the Memorex Storage Module disk drives took over the world of
storage, and nine-track tapes became the standard, the I/O channels
started placing nine 8-bit bytes into two 36-bit words. That became
somewhat painful to unpack.

--
Lars Poulsen
1970-1975 RECKU - University of Copenhagen
Systems Programming/Debugging, Academic Help Desk
Univac 1106 -> 1108 -> 1100/10