6 Jan
2019
6 Jan
'19
1:48 p.m.
On Sun, 2019-01-06 at 12:00 -0600, cctalk-request at classiccmp.org wrote:
Re: off topic - capatob - saratov2 computer Russsian
pdp8
Nothing has changed as regards the number of bits in a byte, a nybble
is 4 bits, 8 to the byte, and x to the word - this last varies widely
depending on architecture.
Still, in Spirit, on an octal processor a whole number is a six bit
'byte', so the term is appropriate, especially to avoid confusion with
the word size of two six bit 'bytes'.
Fun.
Jeff
6 Jan
6 Jan
2:29 p.m.
Sorry, thanks for playing but
Actually half of a WORD is a BYTE, whatever the numerical length is.
Ready for this,half of a BYTE is a NIBBLE. In fact, in common usage,
word has become synonymous with 16 bits, much like byte has with 8
bits.
What's the difference between a word and byte? - Stack Overflow
https://stackoverflow.com/questions/.../whats-the-difference-between-a-word…
Feedback
About this result
On Sun, Jan 6, 2019 at 1:48 PM Jeffrey S. Worley via cctalk
<cctalk at classiccmp.org> wrote:
On Sun, 2019-01-06 at 12:00 -0600, cctalk-request at classiccmp.org wrote:
Re: off topic - capatob - saratov2 computer
Russsian pdp8
Nothing has changed as regards the number of bits in a byte, a nybble
is 4 bits, 8 to the byte, and x to the word - this last varies widely
depending on architecture.
Still, in Spirit, on an octal processor a whole number is a six bit
'byte', so the term is appropriate, especially to avoid confusion with
the word size of two six bit 'bytes'.
Fun.
Jeff
2:34 p.m.
With the advent of wide spread introduction of 16 bit machines the
definition of a byte as an 8 bit unit was accepted because ASCII
supported character sets for multiple languages, before the 8bit
standard there were 6 bit, 7 bit variations of he character sets.
Gee, what were teletypes, like the model 15, 19, 28, oh yeah 5 level
or 5 bit..with no parity.
On Sun, Jan 6, 2019 at 2:29 PM Bob Smith <bobsmithofd at gmail.com> wrote:
Sorry, thanks for playing but
Actually half of a WORD is a BYTE, whatever the numerical length is.
Ready for this,half of a BYTE is a NIBBLE. In fact, in common usage,
word has become synonymous with 16 bits, much like byte has with 8
bits.
What's the difference between a word and byte? - Stack Overflow
https://stackoverflow.com/questions/.../whats-the-difference-between-a-word…
Feedback
About this result
On Sun, Jan 6, 2019 at 1:48 PM Jeffrey S. Worley via cctalk
<cctalk at classiccmp.org> wrote:
>
> On Sun, 2019-01-06 at 12:00 -0600, cctalk-request at classiccmp.org wrote:
> > Re: off topic - capatob - saratov2 computer Russsian pdp8
>
> Nothing has changed as regards the number of bits in a byte, a nybble
> is 4 bits, 8 to the byte, and x to the word - this last varies widely
> depending on architecture.
>
> Still, in Spirit, on an octal processor a whole number is a six bit
> 'byte', so the term is appropriate, especially to avoid confusion with
> the word size of two six bit 'bytes'.
>
> Fun.
>
> Jeff
>
2:46 p.m.
On Jan 6, 2019, at 2:34 PM, Bob Smith via cctalk
<cctalk at classiccmp.org> wrote:
With the advent of wide spread introduction of 16 bit machines the
definition of a byte as an 8 bit unit was accepted because ASCII
supported character sets for multiple languages, before the 8bit
standard there were 6 bit, 7 bit variations of he character sets.
Gee, what were teletypes, like the model 15, 19, 28, oh yeah 5 level
or 5 bit..with no parity.
I think some of this discussion suffers from not going far enough back in history.
"Byte" was a term used a great deal in the IBM/360 series, where it meant 8
bits. Similarly "halfword" (16 bits). But as was pointed out, mainframes in
that era had lots of different word sizes: 27, 32, 36, 48, 60... Some of them (perhaps
not all) also used the term "byte" to mean something different. In the PDP-10,
it has a well defined meaning: any part of a word, as operated on by the "byte"
instructions -- which the VAX called "bit field instructions". 6 and 9 bit
sizes were common for characters, and "byte" without further detail could have
meant any of those. In the CDC 6000 series, characters were 6 or 12 bits, and either of
those could be "byte".
"Nybble" is as far as I can tell a geek joke term, rather than a widely used
standard term. "Halfword" is 16 bits on IBM 360 and VAX, 18 on PDP-10, and
unused on CDC 6000. Then there are other subdivisions with uncommon terms, like
"parcel" (15 bits, CDC 6000 series, the unit used by the instruction issue
path).
ASCII was originally a 7 bit code. There were other 7 bit codes at that time, like the
many variations of Flexowriter codes; 6 bit codes (found in typesetting systems and
related stuff such as news wire service data feeds), and 5 bit codes (Telex codes, again
in many variations).
paul
6:21 p.m.
With the advent of wide spread introduction of 16 bit
machines the
definition of a byte as an 8 bit unit was accepted because ASCII
supported character sets for multiple languages, before the 8bit
standard there were 6 bit, 7 bit variations of he character sets.
Gee, what were teletypes, like the model 15, 19, 28, oh yeah 5 level
or 5 bit..with no parity.
Byte was more or less "set in stone" in the mid 1960s, with the
success of the IBM System/360. During the internal war at IBM to
determine whether the S/360 was going to be a 6 bit based machine or
an 8 bit based machine, a study showed that a huge majority of the
stored digital data in the world was better suited to 8 bits (mainly
because of BCD in the financial industry). It had nothing to do with
terminal communications, as there just was not much of that back then.
When the S/360 turned into the success it was, maybe 1966 or so, it
turned into an eight bit byte world.
People on this list keep forgetting just how gigantic IBM was back
then, and how much influence it had, good or bad.
--
Will
7 Jan
7 Jan
12:24 a.m.
-----Original Message-----
From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of William Donzelli
via cctalk
Sent: 06 January 2019 23:21
To: Bob Smith <bobsmithofd at gmail.com>; General Discussion: On-Topic and
Off-Topic Posts <cctalk at classiccmp.org>
Subject: Re: off topic - capatob - saratov2 computer Russsian pdp8
I am also pretty sure that prior to S/360 the term "character" was generally
used for non 8-bit character machines. I am not familiar with the IBM 70xx series machines
but certainly on the 1401 and 1620 the term byte was never used. Also the Honeywell H3200
which was an IBM1401 "clone" (sort of). The only machine I know where a
"byte" is not eight bits is the Honeywell L6000 and its siblings These machines
had 36 bit works which were originally divided into 6 six bit characters. When it became
clear that the world was moving to 8-bit characters they added new instructions that
allowed a word to be treated as 4 by 9-bit bytes.
I seem to recall that some IBM machines also had facilities to read all 9 bits from a
9-track tape as data so 9-bit bytes but I can't find references.
I also feel the use of the term Octet was more marketing to distance ones machines from
IBM.....
Dave
With the advent of wide spread introduction of 16
bit machines the
definition of a byte as an 8 bit unit was accepted because ASCII
supported character sets for multiple languages, before the 8bit
standard there were 6 bit, 7 bit variations of he character sets.
Gee, what were teletypes, like the model 15, 19, 28, oh yeah 5 level
or 5 bit..with no parity.
Byte was more or less "set in stone" in the mid 1960s, with the success of the
IBM System/360. During the internal war at IBM to determine whether the
S/360 was going to be a 6 bit based machine or an 8 bit based machine, a
study showed that a huge majority of the stored digital data in the world was
better suited to 8 bits (mainly because of BCD in the financial industry). It had
nothing to do with terminal communications, as there just was not much of
that back then.
When the S/360 turned into the success it was, maybe 1966 or so, it turned
into an eight bit byte world.
People on this list keep forgetting just how gigantic IBM was back then, and
how much influence it had, good or bad.
--
Will
9:45 a.m.
On Jan 7, 2019, at 12:24 AM, Dave Wade via cctalk
<cctalk at classiccmp.org> wrote:
...
I am also pretty sure that prior to S/360 the term "character" was generally
used for non 8-bit character machines. I am not familiar with the IBM 70xx series machines
but certainly on the 1401 and 1620 the term byte was never used.
The 1620 is a decimal machine, with digit-addressed memory. It has a number of
instructions that operate on digit pairs, for I/O, so those pairs are called
"characters".
Also the Honeywell H3200 which was an IBM1401
"clone" (sort of). The only machine I know where a "byte" is not eight
bits is the Honeywell L6000 and its siblings These machines had 36 bit works which were
originally divided into 6 six bit characters.
Others have already pointed out there are plenty of other examples, with other
definitions. I mentioned the CDC 6000 series mainframes.
Just to make sure of my memory, I searched some documentation. Here is a quote from the
CDC Cyber 170 series Hardware Reference Manual (section "Input/output multiplexor -
Model 176"):
"During communications between the PPUs and CM, the I/O MUX disassembles 60-bit
transmissions from CM to 12-bit bytes."
But here's one I had not seen before: in the 7600 Preliminary System Description, the
section that describes the PPU I/O machinery has the same sort of wording as above, but
then on the next page the discussion of the drum memory says:
"A 16 bit cyclic parity byte is generated by the controller for the data field of
each record written on the peripheral unit."
And the CDC 6000 series Sort-Merge utility has a "BYTESIZE" control card, which
in PDP-10 fashion allows "byte" to be any length up to 60 bits (the word size)
-- the default is 6 bits, which is character length for the basic character set but other
examples show 12 and 60 bit "bytes". In the same way, a TUTOR language manual
from 1978 describes bytes as being any size, in a description of the language feature for
what C calls bit-field variables. I didn't realize that term was used for that
feature, though.
paul
11:37 a.m.
On 01/06/2019 11:24 PM, Dave Wade via cctalk wrote:
I am also pretty sure that prior to S/360 the term
"character" was generally used for non 8-bit character
machines. I am not familiar with the IBM 70xx series machines
The IBM 7070
(business machine) was a word-addressed
machine, but all decimal.
The IBM 709x series (scientific machine) was also word
addressed, but binary.
I seem to recall that some IBM machines also had
facilities to read all 9 bits from a 9-track tape as data
so 9-bit bytes but I can't find references. I also feel
the use of the term Octet was more marketing to distance
ones machines from IBM..... Dave
The earlier machines were mostly using 7 track
tape, not 9
track. You did have your choice of even or odd parity. I'm
pretty sure that the 360 tape controls did not support any
handling of the 9th track other than parity, and odd parity
was the only option.
Jon
6 Jan
6 Jan
9:10 p.m.
On 01/06/2019 01:29 PM, Bob Smith via cctalk wrote:
Sorry, thanks for playing but
Actually half of a WORD is a BYTE, whatever the numerical length is.
Ready for this,half of a BYTE is a NIBBLE.
Well, no. On 32-bit machines such as
IBM 360, VAX, etc.
half a 32-bit word is a halfword,
the fullword is equal to FOUR bytes. On a 360/65 and above,
the memory word was 64 bits, or a double-word, so half that
was a fullword. Just makes it more confusing.
Jon
11:28 p.m.
On Jan 6, 2019, at 6:10 PM, Jon Elson via cctalk
<cctalk at classiccmp.org> wrote:
On 01/06/2019 01:29 PM, Bob Smith via cctalk wrote:
No it doesn?t. The 360/65 was still a 32-bit processor (as defined by the ISA). It makes
no difference what the width to memory was. Wider memory is only to improve the bandwidth
to memory. That?s like saying the current Intel ixxx CPUs (which are 64-bit ISA) are
?confusing? because the width to memory is 256-bits.
TTFN - Guy
Sorry, thanks for playing but
Actually half of a WORD is a BYTE, whatever the numerical length is.
Ready for this,half of a BYTE is a NIBBLE.
Well, no. On 32-bit machines such as
IBM 360, VAX, etc. half a 32-bit word is a halfword,
the fullword is equal to FOUR bytes. On a 360/65 and above, the memory word was 64 bits,
or a double-word, so half that was a fullword. Just makes it more confusing.
2057
days inactive
2058
days old
9 comments
7 participants
participants (7)
-
bobsmithofd＠gmail.com -
dave.g4ugm＠gmail.com -
elson＠pico-systems.com -
ggs＠shiresoft.com -
paulkoning＠comcast.net -
technoid6502＠gmail.com -
wdonzelli＠gmail.com