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* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-09 18:46 Norman Wilson
  2022-09-10  1:35 ` Paul Winalski
  0 siblings, 1 reply; 26+ messages in thread
From: Norman Wilson @ 2022-09-09 18:46 UTC (permalink / raw)
  To: tuhs

Doug McIlroy:

  Bit-addressing is very helpful for manipulating characters
  in a word-organized memory. The central idea of my ancient
  (patented!) string macros that underlay SNOBOL was that it's
  more efficient to refer to 6-bit characters as living at
  bits 0,6,12,... of a 36-bit word than as being characters
  0,1,2,... of the word. I've heard that this convention was
  supported in hardware on the PDP-10.

====

Indeed it was.  The DEC-10 had `byte pointers' as well as
(36-bit) word addresses.  A byte pointer comprised an address,
a starting bit within the addressed word, and a length.
There were instructions to load and store an addressed byte
to or from a register, and to do same while incrementing
the pointer to the next byte, wrapping the start of the next
word if the remainder of the current word was too small.
(Bytes couldn't span word boundaries.)

Byte pointers were used routinely to process text.  ASCII
text was conventionally stored as five 7-bit bytes packed
into each 36-bit word.  The leftover bit was used by some
programs as a flag to mean these five characters (usually
the first of a line) were special, e.g. represented a
five-decimal-digit line number.

Byte pointers were used to access Sixbit characters as
well (each character six bits, so six to the word,
character set comprising the 64-character subset of
ASCII starting with 0 == space).

Norman Wilson
Toronto ON
(spent about four years playing with TOPS-10 before
growing up to play with UNIX)

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-11 13:30 Douglas McIlroy
  2022-09-11 15:08 ` John Cowan
  2022-09-11 15:30 ` Bakul Shah
  0 siblings, 2 replies; 26+ messages in thread
From: Douglas McIlroy @ 2022-09-11 13:30 UTC (permalink / raw)
  To: TUHS main list

Anecdote prompted by the advent of Burroughs in this thread:

At the 1968 NATO conference on Software Engineering, the discussion
turned to language design strategies. I noted that the design of Algol
68, for example, presupposed a word-based machine, whereupon Burroughs
architect Bob Barton brought the house down with the remark, "In the
beginning was the Word, all right--but it was not a fixed number of
bits!"

[Algol 68's presupposition is visible in declarations like "long long
long ... int". An implementation need support only a limited number of
"longs", but each supported variety must have a definite maximum
value, which is returned by an "environment enquiry" function. For
amusement, consider the natural idea of implementing the longest
variety with bignums.]

Doug

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in        collection of bits?
@ 2022-09-09 19:39 Nelson H. F. Beebe
  2022-09-09 20:27 ` Bakul Shah
  0 siblings, 1 reply; 26+ messages in thread
From: Nelson H. F. Beebe @ 2022-09-09 19:39 UTC (permalink / raw)
  To: tuhs

Paul Winalski and Bakul Shah commented on bit addressable machines
on the TUHS list recently.  From Blaauw and Brooks' excellent
Computer Architecture book

	http://www.math.utah.edu/pub/tex/bib/master.html#Blaauw:1997:CAC

on page 98, I find

>> ...
>> The earliest computer with bit resolution is the [IBM 7030] Stretch.
>> The Burroughs B1700 (1972) and CDC STAR100 (1973) are later examples.
>>
>> Bit resolution is costly in format space, since it uses a maximum
>> number of bits for address and length specification.  Sharpening
>> resolution from the byte to the bit costs the same as increasing
>> address-space size eight-fold.
>>
>> Since almost all storage realizations are organized as matrices,
>> bit resolution is also expensive in time or equipment.
>> ...

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                                                          -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe@math.utah.edu  -
- 155 S 1400 E RM 233                       beebe@acm.org  beebe@computer.org -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
-------------------------------------------------------------------------------

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-09 17:26 Douglas McIlroy
  0 siblings, 0 replies; 26+ messages in thread
From: Douglas McIlroy @ 2022-09-09 17:26 UTC (permalink / raw)
  To: TUHS main list

> Doug or anyone, why do bit pointers make sense?  Why?

Bit-addressing is very helpful for manipulating characters
in a word-organized memory. The central idea of my ancient
(patented!) string macros that underlay SNOBOL was that it's
more efficient to refer to 6-bit characters as living at
bits 0,6,12,... of a 36-bit word than as being characters
0,1,2,... of the word. I've heard that this convention was
supported in hardware on the PDP-10.

In the IBM 7020 floats and ints were word-addressed. But
those addresses could be extended past the "decimal point"
to refer to bits. Bits were important. The computer was designed
in parallel with the Harvest streaming "attachment" for
NSA. Harvest was basically intended to gather statistics useful
in code-breaking, such as frequency counts and autocorrelations,
for data typically encoded in packed 5- to 8-bit characters. It
was controlled by a 20-word "setup" that specified operations on
rectangular and triangular indexing patterns in multidimensional
arrays. Going beyond statistics, one of the operations was SQML
(sequential multiple lookup) where each character was looked
up in a table that specified a replacement and a next table--a
spec for an arbitrary Turing machine that moved its tape at
byte-streaming speed!

Doug

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-09  1:33 Douglas McIlroy
  2022-09-09  2:12 ` Larry McVoy
                   ` (2 more replies)
  0 siblings, 3 replies; 26+ messages in thread
From: Douglas McIlroy @ 2022-09-09  1:33 UTC (permalink / raw)
  To: TUHS main list

 > I heard that the IBM 709
> series had 36 bit words because Arthur Samuel,
> then at IBM, needed 32 bits to identify the playable squares on a
> checkerboard, plus some bits for color and kinged

To be precise, Samuel's checkers program was written for
the 701, which originated the architecture that the 709 inherited.

Note that IBM punched cards had 72 data columns plus 8
columns typically dedicated to sequence numbers. 700-series
machines supported binary IO encoded two words per row, 12
rows per card--a perfect fit to established technology. (I do
not know whether the fit was deliberate or accidental.)

As to where the byte came from, it was christened for the IBM
Stretch, aka 7020. The machine was bit-addressed and the width
of a byte was variable. Multidimensional arrays of packed bytes
could be streamed at blinding speeds. Eight bits, which synced
well with the 7020's 64-bit words, was standardized in the 360
series. The term "byte" was not used in connection with
700-series machines.

Doug

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-08 21:16 Noel Chiappa
  2022-09-08 21:24 ` Dan Halbert
  0 siblings, 1 reply; 26+ messages in thread
From: Noel Chiappa @ 2022-09-08 21:16 UTC (permalink / raw)
  To: tuhs; +Cc: jnc

    > From: Jim Capp

    > See "The Preparation of Programs for an Electronic Digital Computer",
    > by Maurice V. Wilkes, David J. Wheeler, and Stanley Gill

Blast! I looked in the index in my copy (ex the Caltech CS Dept Library :-),
but didn't find 'word' in the index!

Looking a little further, Turing's ACE Report, from 1946, uses the term
(section 4, pg. 25; "minor cycle, or word"). My copy, the one edited by
Carpenter and Doran, has a note #1 by them, "Turing seems to be the first
user of 'word' with this meaning." I have Brian's email, I can ask him how
they came to that determination, if you'd like.

There aren't many things older than that! I looked quickly through the "First
Draft on the EDVAC", 1945 (re-printed in "From ENIAC to UNIVAC", by Stein),
but did not see word there. It does use the term "minor cycle", though.

Other places worth checking are the IBM/Harvard Mark I, the ENIAC and ...
I guess therer's not much else! Oh, there was a relay machine at Bell, too.
The Atanasoff-Berry computer?


    > From: "John P. Linderman"

    > He claims that if you wanted to do decimal arithmetic on a binary
    > machine, you'd want to have 10 digits of accuracy to capture the 10
    > digit log tables that were then popular.

The EDVAC draft talks about needing 8 decimal digits (Appendix A, pg.190);
apparently von Neumann knew that that's how many digits one needed for
reasonable accuracy in differential equations. That is 27 "binary digits"
(apparently 'bit' hadn't been coined yet).

	Noel

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-08 18:20 Noel Chiappa
  2022-09-08 19:28 ` Jim Capp
  0 siblings, 1 reply; 26+ messages in thread
From: Noel Chiappa @ 2022-09-08 18:20 UTC (permalink / raw)
  To: tuhs; +Cc: jnc

    > It was used, in the modern sense, in "Planning a Computer System",
    > Buchholz,1962.

Also in the IBM "650 Manual of Operation", June, 1955. (Before I was
born! :-)

	Noel

^ permalink raw reply	[flat|nested] 26+ messages in thread
* [TUHS] Does anybody know the etymology of the term "word" as in collection of bits?
@ 2022-09-08 16:51 Jon Steinhart
  2022-09-08 16:56 ` [TUHS] " Andrew Hume
  2022-09-08 17:28 ` Dan Halbert
  0 siblings, 2 replies; 26+ messages in thread
From: Jon Steinhart @ 2022-09-08 16:51 UTC (permalink / raw)
  To: TUHS

One of those questions for which there is no search engine incantation.

Jon

^ permalink raw reply	[flat|nested] 26+ messages in thread

end of thread, other threads:[~2022-09-16  5:56 UTC | newest]

Thread overview: 26+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-09 18:46 [TUHS] Re: Does anybody know the etymology of the term "word" as in collection of bits? Norman Wilson
2022-09-10  1:35 ` Paul Winalski
  -- strict thread matches above, loose matches on Subject: below --
2022-09-11 13:30 Douglas McIlroy
2022-09-11 15:08 ` John Cowan
2022-09-11 15:30 ` Bakul Shah
2022-09-11 15:45   ` Paul Winalski
2022-09-11 16:20     ` Steve Nickolas
2022-09-09 19:39 Nelson H. F. Beebe
2022-09-09 20:27 ` Bakul Shah
2022-09-09 21:12   ` Henry Bent
2022-09-09 21:44   ` Dave Horsfall
2022-09-09 17:26 Douglas McIlroy
2022-09-09  1:33 Douglas McIlroy
2022-09-09  2:12 ` Larry McVoy
2022-09-13 14:23   ` John Foust via TUHS
2022-09-09  2:45 ` George Michaelson
2022-09-16  5:55 ` Marc Donner
2022-09-08 21:16 Noel Chiappa
2022-09-08 21:24 ` Dan Halbert
2022-09-08 18:20 Noel Chiappa
2022-09-08 19:28 ` Jim Capp
2022-09-08 16:51 [TUHS] " Jon Steinhart
2022-09-08 16:56 ` [TUHS] " Andrew Hume
2022-09-08 17:28 ` Dan Halbert
2022-09-09  0:00   ` Greg 'groggy' Lehey
2022-09-09 15:49     ` Paul Winalski
2022-09-09 18:44       ` Bakul Shah

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