Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Pontus Pihlgren via cctalk]

Hi again

Olafs also found this:
http://www.nedopc.org/forum/viewtopic.php?t=9778

Unless you know russian, maybe you can use google translate.

Regards,
Pontus.

On Tue, Jan 08, 2019 at 11:06:12AM +0100, Pontus Pihlgren via cctalk 
wrote:
> Hi Iain
> 
> I asked a guy from Latvia that I know, Olafs. He recognized the 
> transistors as KT315 A and B. Collector is middle pin.
> 
> https://en.wikipedia.org/wiki/KT315
> 
> He might also be able to help with spare lights, contact me off-list. 
> Unfortunately he has no documentation.
> 
> /P
> 
> On Sat, Jan 05, 2019 at 06:36:56PM +, Dr Iain Maoileoin via cctalk 
> wrote:
> > Off topic, but looking for help and/or wisdom.
> > 
> > If you visit https://www.scotnet.co.uk/iain/saratov 
> > /  
> > you will see some photos and wire-lists of work that I have started on the 
> > front panel of a Capatob 2.
> > 
> > I plan to get the switches and lights running on a blinkenbone board with a 
> > PDP8 emulation behind it.  (I already have an PDP11/70 front-panel running 
> > on the same infrastructure)
> > 
> > I have been struggling for over a year to get much info about this saratov 
> > computer (circuit diagrams etc).  So I have started the reverse engineering 
> > on the panel.
> > 
> > Does anybody know anything about this computer?  online or offline it would 
> > be much appreciated.
> > 
> > Iain

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Pontus Pihlgren via cctalk]

Hi Iain

I asked a guy from Latvia that I know, Olafs. He recognized the 
transistors as KT315 A and B. Collector is middle pin.

https://en.wikipedia.org/wiki/KT315

He might also be able to help with spare lights, contact me off-list. 
Unfortunately he has no documentation.

/P

On Sat, Jan 05, 2019 at 06:36:56PM +, Dr Iain Maoileoin via cctalk 
wrote:
> Off topic, but looking for help and/or wisdom.
> 
> If you visit https://www.scotnet.co.uk/iain/saratov 
> /  
> you will see some photos and wire-lists of work that I have started on the 
> front panel of a Capatob 2.
> 
> I plan to get the switches and lights running on a blinkenbone board with a 
> PDP8 emulation behind it.  (I already have an PDP11/70 front-panel running on 
> the same infrastructure)
> 
> I have been struggling for over a year to get much info about this saratov 
> computer (circuit diagrams etc).  So I have started the reverse engineering 
> on the panel.
> 
> Does anybody know anything about this computer?  online or offline it would 
> be much appreciated.
> 
> Iain

Re: so far off topic - capatob - saratov2 computer Russsian pdp8?

[Jon Elson via cctalk]

On 01/07/2019 07:51 PM, allison via cctalk wrote:
I still want to make a stretched 8, PDP8 ISA with 16 bits 
and faster. No good reason save for it wold be fun.

Umm, I think that is called a Data General Nova!

Jon

Re: so far off topic - capatob - saratov2 computer Russsian pdp8?

[allison via cctalk]

On 01/07/2019 07:25 PM, ben via cctalk wrote:
> On 1/7/2019 8:20 AM, allison via cctalk wrote:
> snip...
>> made though more likely 74F, AS, or LS variant and of course CMOS 74ACT
>> (and cmos friends) as I just bought a bunch.  Dip is getting harder to
>> get but
>> the various SMT packages are easy.  Prices for 10 or more of a part are
>> cheap to cheaper from primary suppliers.  The second tier suppliers are
>> often several times that.
>
> I got ebay... The bottom of the heap.
>
>> I figure most of what I did back then is years before many here were
>> born.
>>
>> However I have enough NOS TTL 74LS, 74AS, 74F series to build several
>> machines.
>
> I have been playing around with a early 70's TTL computer design
> and 74LS181's are too slow by 30 ns. Using a BLACK BOX model for core
> memory, I can get a 1.2us memory cycle using a 4.912 MHz raw clock
> but I need a few 74Hxx's in there. Proms are 256x4 60 ns and 32x8 50 ns.
>
> Do you have your 74Hxx spares? Eastern Europe still  has a few on ebay
> with reasonable shipping for 100% American Russian parts.
>
No use for 74H parts though I have a bunch.

the 74LS are slow  you are paying for lower power with speed.  tHe 74181
and 74S181 were far faster.

Proms are small and slow, last time I used them was for the address
decode used on the Northstar* MDS-A controller.

I built the last big machine with ram back 1980 and was in the 1us
instruction
cycle time for single cycle instructions without pipelines.  Core was never
considered.  Trick is throw hardware at it.  Adding adders to the address
calculation rather than reuse the ALU saves a lot of time and wires.   Not
like it was for manufacture or anything like that.  More of an exercise.

I still want to make a stretched 8, PDP8 ISA with 16 bits and faster.
No good reason save for it wold be fun.
>> I'm still building, current project is a very compact Z80 CP/M system
>> using CF
>> for disk. Mine uses all Zilog CMOS for very low power.  Its a variant of
>> the
>> Grant Searle Z80 with memory management added to utilize all of the
>> 124k ram and eeprom.  If you want go look there.
>
> What do you use all that memory for?
>
CP/M the allocation block store for each drive and deblocking buffers
for performance
can be large plus its easy to hide part of the Bios in banked ram. 
Background processes
are easier when you have lots of ram for that.  Most of the larger aps
like C compilers
and such run better with more than 48K, 56k is easy, and 60k is doable
with the
right memory map.

For EEprom its more than boot, the system is in EEprom (about 8K) and
with 32K
or more things like romdisks and utilities are easily parked there.

I've been building nonstandard CP/M systems since 79.  In all cases he
aps think
it is standard CP/M but the bios and such have been tuned even CP/M Bdos
it self.
Though I often use ZRdos or ZSdos as they are very good.  Not much you
cant do
to it.

Allison
>>
>
> The Chinese elves have been busy, My 5V 15 amp $20 power supply arrived
> in the mail today. I have power to spare for my BUS and blinking lights.
>
So long as you load it at least 10% it will be good.

> Ben.
>
>

Re: so far off topic - capatob - saratov2 computer Russsian pdp8?

[ben via cctalk]

On 1/7/2019 8:20 AM, allison via cctalk wrote:
snip...

made though more likely 74F, AS, or LS variant and of course CMOS 74ACT
(and cmos friends) as I just bought a bunch.  Dip is getting harder to
get but
the various SMT packages are easy.  Prices for 10 or more of a part are
cheap to cheaper from primary suppliers.  The second tier suppliers are
often several times that.


I got ebay... The bottom of the heap.


I figure most of what I did back then is years before many here were born.

However I have enough NOS TTL 74LS, 74AS, 74F series to build several
machines.


I have been playing around with a early 70's TTL computer design
and 74LS181's are too slow by 30 ns. Using a BLACK BOX model for core 
memory, I can get a 1.2us memory cycle using a 4.912 MHz raw clock

but I need a few 74Hxx's in there. Proms are 256x4 60 ns and 32x8 50 ns.

Do you have your 74Hxx spares? Eastern Europe still  has a few on ebay
with reasonable shipping for 100% American Russian parts.


I'm still building, current project is a very compact Z80 CP/M system
using CF
for disk. Mine uses all Zilog CMOS for very low power.  Its a variant of
the
Grant Searle Z80 with memory management added to utilize all of the
124k ram and eeprom.  If you want go look there.


What do you use all that memory for?


Allison



The Chinese elves have been busy, My 5V 15 amp $20 power supply arrived
in the mail today. I have power to spare for my BUS and blinking lights.

Ben.

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Jon Elson via cctalk]

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

Re: so far off topic - capatob - saratov2 computer Russsian pdp8?

[allison via cctalk]

On 01/07/2019 09:51 AM, Peter Corlett via cctalk wrote:
> On Sun, Jan 06, 2019 at 02:54:08PM -0700, ben via cctalk wrote:
>> On 1/6/2019 12:24 PM, allison via cctalk wrote:
>>> The small beauty of being there...   FYI back then (1972) a 7400 was about
>>> 25 cents and 7483 adder was maybe $1.25.  Least that's what I paid.
>> Checks my favorite supplier.
>> $1.25 for 7400 and $4.00 for a 7483.
>> It has gone up in price.
> Thanks to inflation, $0.25 in 1972 is worth $1.51 now. Likewise, $1.25 has
> inflated to $7.54. So they're cheaper in real terms than they used to be.
>
> However, it's still not entirely comparable, as I suspect nobody's making
> 74-series chips any more so you're buying NOS. A modern equivalent would be a
> microcontroller, which start at well under a dollar.
>
First I wasn't guessing back.  I was building and buying back then. So
that was what I
actually paid in 1972,  I've been at it since RTL hit the streets.   The
74 series still
made though more likely 74F, AS, or LS variant and of course CMOS 74ACT
(and cmos friends) as I just bought a bunch.  Dip is getting harder to
get but
the various SMT packages are easy.  Prices for 10 or more of a part are
cheap to cheaper from primary suppliers.  The second tier suppliers are
often several times that.

I figure most of what I did back then is years before many here were born.

However I have enough NOS TTL 74LS, 74AS, 74F series to build several
machines. 

I'm still building, current project is a very compact Z80 CP/M system
using CF
for disk. Mine uses all Zilog CMOS for very low power.  Its a variant of
the
Grant Searle Z80 with memory management added to utilize all of the
124k ram and eeprom.  If you want go look there.

Allison

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Kyle Owen via cctalk]

On Mon, Jan 7, 2019 at 8:51 AM Peter Corlett via cctalk <
cctalk@classiccmp.org> wrote:

> Thanks to inflation, $0.25 in 1972 is worth $1.51 now. Likewise, $1.25 has
> inflated to $7.54. So they're cheaper in real terms than they used to be.
>
> However, it's still not entirely comparable, as I suspect nobody's making
> 74-series chips any more so you're buying NOS. A modern equivalent would
> be a
> microcontroller, which start at well under a dollar.
>

Logic chips still have their uses, and are most certainly still being made.
You can still get 74LS parts, in a DIP package even:
https://www.digikey.com/product-detail/en/texas-instruments/SN74LS00N/296-1626-5-ND/277272

Note: it's an active production part, too.

Kyle

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Peter Corlett via cctalk]

On Sun, Jan 06, 2019 at 02:54:08PM -0700, ben via cctalk wrote:
> On 1/6/2019 12:24 PM, allison via cctalk wrote:
>> The small beauty of being there...   FYI back then (1972) a 7400 was about
>> 25 cents and 7483 adder was maybe $1.25.  Least that's what I paid.
> Checks my favorite supplier.
> $1.25 for 7400 and $4.00 for a 7483.
> It has gone up in price.

Thanks to inflation, $0.25 in 1972 is worth $1.51 now. Likewise, $1.25 has
inflated to $7.54. So they're cheaper in real terms than they used to be.

However, it's still not entirely comparable, as I suspect nobody's making
74-series chips any more so you're buying NOS. A modern equivalent would be a
microcontroller, which start at well under a dollar.

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Paul Koning via cctalk]

> On Jan 7, 2019, at 12:24 AM, 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 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

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Noel Chiappa via cctalk]

> From: Dave Wade

> The only machine I know where a "byte" is not eight bits is the
> Honeywell L6000 and its siblings

I'm not sure why I bother to post to this list, since apparently people don't
bother to read my messages.

>From the "pdp10 reference handbook", 1970, section 2.3, "Byte Manipulation",
page 2-15:

"This set of five instructions allows the programmer to pack or unpack bytes
of any length from anywhere within a word. ... The byte manipulation
instructions have the standard memory reference format, but the effective
address E is used to retrieve a pointer, which is used in turn to locate
the byte ... The pointer has the format

 0   5 6   11 12 13 14   17 18   35
   P S   I X   Y

where S is the size of the byte as a number of bits, and P as its position
as the number of bits remaining at the right of the byte in the word ... To
facilitate processing a series of bytes, several of the byte instructions
increment the pointer, ie modify it so that it points to the next byte
position in a set of memory locations. Bytes are processed from left to
right in a word, so incrementing merely replaces the current value of P
by P-S, unless there is insufficient space in the present location [i.e.
'word' - JNC] for another byte of the specified size (P-S < 0). In this
case Y is increased by one to point at the next consecutive location, and
P is set to 36 - S to point to the first byte at the left in the new
location."

Now imagine implementing all that in FLIP CHIPs which held transistors
(this is before ICs)!

Anyway, like I said, at least ITS (of the PDP-10 OS's) used this to store
ASCII in words which contain five 7-bit _bytes_. I don't know if TENEX did.


> I also feel the use of the term Octet was more marketing to distance
> ones machines from IBM.

Huh? Which machine used the term 'octet'?

Like I said, we adapted and used the term 'octet' in TCP/IP documentation
(and that's definite - go check out historical documents, e.g. RFC-675 from
1974) because 'byte' was at the time ambiguous - the majority of machines on
the ARPANET at that point were PDP-10's (see above).

Interestingly, I see it's not defined in that document (or in the earlier
RFC-635), so it must have already been in use for an 8-bit quantity?

Doing a little research, there is a claim that Bob Bemer independently
invented the term in 1965/66. Perhaps someone subconciously remembered his
proposal, and that's the ultimate source? The term is also long used in
chemistry and music, of course, so perhaps that's where it came from.

Noel

RE: off topic - capatob - saratov2 computer Russsian pdp8

[Dave Wade via cctalk]

> -Original Message-
> From: cctalk  On Behalf Of William Donzelli
> via cctalk
> Sent: 06 January 2019 23:21
> To: Bob Smith ; General Discussion: On-Topic and
> Off-Topic Posts 
> Subject: Re: off topic - capatob - saratov2 computer Russsian pdp8
> 
> > 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

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

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Guy Sotomayor Jr via cctalk]

> On Jan 6, 2019, at 6:10 PM, Jon Elson via cctalk  
> wrote:
> 
> 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.

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

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Jon Elson via cctalk]

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

Re: off topic - capatob - saratov2 computer Russsian pdp8

[William Donzelli via cctalk]

> 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

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[William Donzelli via cctalk]

> - some marketing person made it up

You believed them? Have your head examined.

> - they were only counting things that were general-purpose (i.e. came with
>   mass storage and compilers)

Conditions, conditions.

> - they didn't consider micros as "computers" (many were used in things like
>   printers, etc, and were not usable as general-purpose computers)

Well, that is DECish, ignoring the coming tsunami of micros. Wow, did
they pay the price...

--
Will

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Noel Chiappa via cctalk]

> From: William Donzelli

>> in 1980, there were more PDP-11's, world-wide, than any other kind of
>> computer.

> I bet the guys at Zilog might have something to talk to you about.

I was quoting my memory of a DEC ad in the WSJ, which now that I go check,
says the -11 was "the best-selling computer in the world" (the ad was in
1980). There are a number of possible explanations as to why it makes this
claim:

- some marketing person made it up
- they were only counting things that were general-purpose (i.e. came with
  mass storage and compilers)
- they didn't consider micros as "computers" (many were used in things like
  printers, etc, and were not usable as general-purpose computers)

Etc, etc.

 Noel

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[ben via cctalk]

On 1/6/2019 12:24 PM, allison via cctalk wrote:


The small beauty of being there...   FYI back then (1972) a 7400 was
about 25 cents
and 7483 adder was maybe $1.25.  Least that's what I paid.

Checks my favorite supplier.

$1.25 for 7400 and $4.00 for a 7483.
It has gone up in price.

Allison


Ben.

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Paul Koning via cctalk]

> On Jan 6, 2019, at 2:34 PM, Bob Smith via cctalk  
> 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

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[allison via cctalk]

On 01/06/2019 01:54 PM, William Donzelli via cctalk wrote:
>> And then the PDP-11 put the nail in that coffin (and in 1980, there were more
>> PDP-11's, world-wide, than any other kind of computer).
> I bet the guys at Zilog might have something to talk to you about.
>
> --
> Will
And Intel!  8008 and 8080 was a byte machine as was 8085, z80,  8088,
6800, 6502, and a long list to follow.

The PDP-11 was unique that it was 8/16 bit in that memory (and by
default IO) supported both byte and word
reads and write.   Instructions were 16bit but data was byte word.  

There were more  Z80 based machines (TRS-80 alone exceeded 250,000) than
PDP-11.
History guys, we are about history!

Allison

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Bob Smith via cctalk]

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  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-and-byte
> Feedback
> About this result
>
> On Sun, Jan 6, 2019 at 1:48 PM Jeffrey S. Worley via cctalk
>  wrote:
> >
> > On Sun, 2019-01-06 at 12:00 -0600, cctalk-requ...@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
> >

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[allison via cctalk]

On 01/06/2019 02:08 PM, Grant Taylor via cctalk wrote:
> On 1/6/19 11:25 AM, Guy Sotomayor Jr via cctalk wrote:
>> I think it’s also telling that the IETF uses the term octet in all of
>> the specifications to refer to 8-bit sized data.  As “byte” (from
>> older machines) could be anything and is thus somewhat ambiguous.
>>
>> It *may* have been the IBM 360 that started the trend of Byte ==
>> 8-bits as the 360’s memory (in IBM’s terms) was byte addressable and
>> the instructions for accessing them were “byte” instructions (as
>> opposed to half-word and word instructions).
>
Yes it was.

Machines around them and in that time frame (mainframe) were 12, 18, 36,
60 bit words.

The big break was mid 1970s with micros first 8008, 8080, 6800 and
bigger machines
like PDP11 (did byte word reads and writes) and TI990.

The emergence of VAX and other 32bit machines made 8bit common as
terminal IO was
starting to standardize.

> Thank you for the clarification.
>
> My take away is that before some nebulous point in time (circa IBM's
> 360) a "byte" could be a number of different bits, depending on the
> computer being discussed.  Conversely, after said nebulous point in
> time a byte was standardized on 8-bits.
>
> Is that fair and accurate enough?  -  I'm wanting to validate the
> patch before I apply it to my mental model of things.  ;- 

There is no hard before and after as systems like DEC10 and other
persisted for a while.  Also part of it was IO codes for the
EBDIC, Flexowriter, ASr33 (8level vs Baudot), and CRT terminals emerging
with mostly IBM or ANSI.

I am somewhat DEC and personal computer (pre IBM PC) centric on this as
they were he machines I got to see
and work with that were not in rooms with glass and white coated
specialists.

Allison

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Bob Smith via cctalk]

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-and-byte
Feedback
About this result

On Sun, Jan 6, 2019 at 1:48 PM Jeffrey S. Worley via cctalk
 wrote:
>
> On Sun, 2019-01-06 at 12:00 -0600, cctalk-requ...@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
>

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[allison via cctalk]

On 01/06/2019 01:19 PM, Noel Chiappa via cctalk wrote:
> > From: Grant Taylor
>
> > Is "byte" the correct term for 6-bits?  I thought a "byte" had always 
> > been 8-bits.
>
> I don't claim wide familiary with architectural jargon from the early days,
> but the PDP-10 at least (I don't know about other prominent 36-bit machines
> such as the IBM 7094/etc, and the GE 635/645) supported 'bytes' of any size,
> with 'byte pointers' used in a couple of instructions which could extract and
> deposit 'bytes' from a word; the pointers specified the starting bit, and the
> width of the 'byte'. These were used for both SIXBIT (an early character
> encoding), and ASCII (7-bit bytes, 5 per word, with one bit left over).
As far as what other systems supported especially the 7094 and GE, that
is already out
of context as the focus was a Russian PDP-8 clone.  Any other machines
are then thread
contamination or worse.

In the early days a byte was the smallest recognized group of bits for
that system
and in some case its 9 bits, 6bits as they were even divisible segments
of the machine
word.  This feature was the bane of programmers as everyone had a
different idea
of what it was and it was poison to portability.

For PDP-8 and friends it was 6 bits and was basically a halfword, also
used as stated for
6bit subset of ASCII (uppercase, TTY codes).  Most of the 8 series had
the bit mapped
instructions (DEC called the microcoded) for doing BSW, byte swap,  swap
the
lower half of the ACC with the upper half.  Very handy for doing
character IO.

> > I would have blindly substituted "word" in place of "byte" except for
> > the fact that you subsequently say "12-bit words". I don't know if
> > "words" is parallel on purpose, as in representing a quantity of two
> > 6-bit word.
>
> I think 'word' was usually used to describe the instruction size (although
> some machines also supported 'half-word' instructions), and also the
> machine's 'ordinary' length - e.g. for the accumulator(s), the quantum of
> data transfer to/from memory, etc. Not necessarily memory addresses, mind -
> on the PDP-10, those were 18 bits (i.e. half-word) - although the smallest
> thing _named_ by a memory addresses was usually a word.
>
>   Noel
The PDP-8 and 12bit relations the instruction word and basic
architecture was 12bit word.
There were no instructions that were a half word in length or other
fragmentations.  The
machine was fairly simple and all the speculated concepts were well
outside the design
of the PDP-5/8 family.   For all of those the instruction fetch, memory
reads and write
were always words of 12bits.   I'd expect a Russian PDP-8 clone to be
the same.   After
all DEC did widely gave out the data books with nearly everything but
schematics.  The
value of copying is software is also copied.  It happened here with the
DCC-112 a
PDP-8e functional clone.

While its possible to use half word ram with reconstruction the hardware
cost is high
(registers to store the pieces) and it would take more to do that than
whole 12bit words.
Any time you look at old machine especially pre-IC registers were costly
and only done
as necessity dictated as a single bit flipflop was likely 4 transistors
(plus diodes and other
components) or more to implement never minding gating. 

Minor history and thread relative drift... 
The only reason people didn't build their own PDP-8 in the early 70s was
CORE.  It was
the one part a early personal computer (meaning personally owned then) 
was difficulty
to duplicate and expensive outright buy.  Trying to make "random" core
planes that
were available work was very difficult due to lack of data, critical
timing, and the
often minimal bench (and costly) test equipment.   The minimum gear for
seeing
the timing was a Tek-516 and that was $1169(1969$).   Semiconductor ram was
either a few bits (4x4) or 1101 (three voltage 256x1) at about 8$ in
1972 dollars.  That
made the parts for a 256x12 a weeks pay at that time (pre-8008) and a
4Kx12 with parts
was nearly that of a new truck (2100$)!.   Compared the basic logic of
the 8e (only
three boards of SSI TTL) core/ram was the show stopper.  About 7 years
later a 8K8
S100 ram was about  (early 1979) 100$, by 1980 64kx8 was 100$.   Moore's
law was
being felt.

The small beauty of being there...   FYI back then (1972) a 7400 was
about 25 cents
and 7483 adder was maybe $1.25.  Least that's what I paid.

Allison

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Grant Taylor via cctalk]

On 1/6/19 11:25 AM, Guy Sotomayor Jr via cctalk wrote:
I think it’s also telling that the IETF uses the term octet in all of 
the specifications to refer to 8-bit sized data.  As “byte” (from 
older machines) could be anything and is thus somewhat ambiguous.


It *may* have been the IBM 360 that started the trend of Byte == 8-bits 
as the 360’s memory (in IBM’s terms) was byte addressable and the 
instructions for accessing them were “byte” instructions (as opposed 
to half-word and word instructions).


Thank you for the clarification.

My take away is that before some nebulous point in time (circa IBM's 
360) a "byte" could be a number of different bits, depending on the 
computer being discussed.  Conversely, after said nebulous point in time 
a byte was standardized on 8-bits.


Is that fair and accurate enough?  -  I'm wanting to validate the patch 
before I apply it to my mental model of things.  ;-)




--
Grant. . . .
unix || die

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[William Donzelli via cctalk]

> And then the PDP-11 put the nail in that coffin (and in 1980, there were more
> PDP-11's, world-wide, than any other kind of computer).

I bet the guys at Zilog might have something to talk to you about.

--
Will

Re: off topic - capatob - saratov2 computer Russsian pdp8

[Jeffrey S. Worley via cctalk]

On Sun, 2019-01-06 at 12:00 -0600, cctalk-requ...@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

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Noel Chiappa via cctalk]

> From: Guy Sotomayor Jr

> I think it's also telling that the IETF uses the term octet in all of
> the specifications to refer to 8-bit sized data.

Yes; at the time the TCP/IP specs were done, PDP-10's were still probably the
most numerous machines on the 'net, so we were careful to use 'octet'.

Although the writing was clearly on the wall, which is why it's all in octets,
with no support for other-length words (unlike the ARPANET, which sort of
supported word lengths which were not a multiple of 8 or 16 - which was
actually use to transfer binary data between 36-bit machines).

> It *may* have been the IBM 360 that started the trend of Byte =
> 8-bits

Yup.

And then the PDP-11 put the nail in that coffin (and in 1980, there were more
PDP-11's, world-wide, than any other kind of computer).

 Noel

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Guy Sotomayor Jr via cctalk]

I think it’s also telling that the IETF uses the term octet in all of the 
specifications to
refer to 8-bit sized data.  As “byte” (from older machines) could be anything 
and is
thus somewhat ambiguous.

It *may* have been the IBM 360 that started the trend of Byte == 8-bits as the 
360’s
memory (in IBM’s terms) was byte addressable and the instructions for accessing
them were “byte” instructions (as opposed to half-word and word instructions).

TTFN - Guy

> On Jan 6, 2019, at 10:19 AM, Noel Chiappa via cctalk  
> wrote:
> 
>> From: Grant Taylor
> 
>> Is "byte" the correct term for 6-bits?  I thought a "byte" had always 
>> been 8-bits.
> 
> I don't claim wide familiary with architectural jargon from the early days,
> but the PDP-10 at least (I don't know about other prominent 36-bit machines
> such as the IBM 7094/etc, and the GE 635/645) supported 'bytes' of any size,
> with 'byte pointers' used in a couple of instructions which could extract and
> deposit 'bytes' from a word; the pointers specified the starting bit, and the
> width of the 'byte'. These were used for both SIXBIT (an early character
> encoding), and ASCII (7-bit bytes, 5 per word, with one bit left over).
> 
>> I would have blindly substituted "word" in place of "byte" except for
>> the fact that you subsequently say "12-bit words". I don't know if
>> "words" is parallel on purpose, as in representing a quantity of two
>> 6-bit word.
> 
> I think 'word' was usually used to describe the instruction size (although
> some machines also supported 'half-word' instructions), and also the
> machine's 'ordinary' length - e.g. for the accumulator(s), the quantum of
> data transfer to/from memory, etc. Not necessarily memory addresses, mind -
> on the PDP-10, those were 18 bits (i.e. half-word) - although the smallest
> thing _named_ by a memory addresses was usually a word.
> 
>   Noel

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Noel Chiappa via cctalk]

> From: Grant Taylor

> Is "byte" the correct term for 6-bits?  I thought a "byte" had always 
> been 8-bits.

I don't claim wide familiary with architectural jargon from the early days,
but the PDP-10 at least (I don't know about other prominent 36-bit machines
such as the IBM 7094/etc, and the GE 635/645) supported 'bytes' of any size,
with 'byte pointers' used in a couple of instructions which could extract and
deposit 'bytes' from a word; the pointers specified the starting bit, and the
width of the 'byte'. These were used for both SIXBIT (an early character
encoding), and ASCII (7-bit bytes, 5 per word, with one bit left over).

> I would have blindly substituted "word" in place of "byte" except for
> the fact that you subsequently say "12-bit words". I don't know if
> "words" is parallel on purpose, as in representing a quantity of two
> 6-bit word.

I think 'word' was usually used to describe the instruction size (although
some machines also supported 'half-word' instructions), and also the
machine's 'ordinary' length - e.g. for the accumulator(s), the quantum of
data transfer to/from memory, etc. Not necessarily memory addresses, mind -
on the PDP-10, those were 18 bits (i.e. half-word) - although the smallest
thing _named_ by a memory addresses was usually a word.

Noel

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Grant Taylor via cctalk]

On 1/6/19 7:08 AM, Bob Smith via cctalk wrote:
What is called the 8 is really based on the 5, used 6-bit bytes, 12 bit 
words, and was Octal based


Is "byte" the correct term for 6-bits?  I thought a "byte" had always 
been 8-bits.  But I started paying attention in the '90s, so I missed a lot.


I would have blindly substituted "word" in place of "byte" except for 
the fact that you subsequently say "12-bit words".  I don't know if 
"words" is parallel on purpose, as in representing a quantity of two 
6-bit word.


Will someone please explain what I'm missing that transpired before I 
started paying attention in the '90s?




--
Grant. . . .
unix || die

Re: off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Bob Smith via cctalk]

https://hapoc2015.sciencesconf.org/file/176702

gives a Little more history on Soviet copies of computers.
The timing of the production of the Capatob 2 seems to make it a
PDP8/L clone, not an M. What is called the 8 is really based on the 5,
used 6-bit bytes, 12 bit words, and was Octal based - memory was the
most expensive part of the system at least through the early 70s, and
thus 12 bit words for double precision, 24bits, was a reasonable
approach for a scientific computer.
bb

On Sat, Jan 5, 2019 at 1:37 PM Dr Iain Maoileoin via cctalk
 wrote:
>
> Off topic, but looking for help and/or wisdom.
>
> If you visit https://www.scotnet.co.uk/iain/saratov 
> /  
> you will see some photos and wire-lists of work that I have started on the 
> front panel of a Capatob 2.
>
> I plan to get the switches and lights running on a blinkenbone board with a 
> PDP8 emulation behind it.  (I already have an PDP11/70 front-panel running on 
> the same infrastructure)
>
> I have been struggling for over a year to get much info about this saratov 
> computer (circuit diagrams etc).  So I have started the reverse engineering 
> on the panel.
>
> Does anybody know anything about this computer?  online or offline it would 
> be much appreciated.
>
> Iain

off topic - capatob - saratov2 computer Russsian pdp8? HELP

[Dr Iain Maoileoin via cctalk]

Off topic, but looking for help and/or wisdom.

If you visit https://www.scotnet.co.uk/iain/saratov 
/  you 
will see some photos and wire-lists of work that I have started on the front 
panel of a Capatob 2.

I plan to get the switches and lights running on a blinkenbone board with a 
PDP8 emulation behind it.  (I already have an PDP11/70 front-panel running on 
the same infrastructure)

I have been struggling for over a year to get much info about this saratov 
computer (circuit diagrams etc).  So I have started the reverse engineering on 
the panel.

Does anybody know anything about this computer?  online or offline it would be 
much appreciated.

Iain