[ih] "network unix"

[brian.e.carpenter at gmail.com (Brian E Carpenter)]

PDP-8/e? Too modern for me! That was definitely a retro-fit to the architecture.

Regards
   Brian

On 10/10/2016 14:31, Jack Haverty wrote:
> Opcode 7002.  From Wikipedia:
> 
> 7002 ? BSW ? Byte Swap 6-bit "bytes" (PDP 8/e and up)
> 
> /Jack
> 
> On 10/09/2016 03:12 PM, Brian E Carpenter wrote:
>> I don't recall a 6-bit byte notion in the PDP-8. The smallest addressable unit
>> was the 12-bit word, and the primary I/O device was an 8-bit ASR33 (which read
>> into bits 4 through 11 of the 12-bit accumulator, the 1966 manual reminds me).
>> Of course you could squeeze upper case ASCII down to 6 bits and store two
>> characters per word to save core memory; I expect I did that but this was 1969
>> so I don't quite remember.  Unlike some of my cohort, I didn't pad out my
>> dissertation by including source code, so it's long lost.
>>
>> Regards
>>    Brian
>>
>> On 10/10/2016 08:57, Jack Haverty wrote:
>>> Wow, people are actually reading this stuff...   Thanks to everyone who
>>> pointed out that PDP-8s didn't have 8-bit byte.  Tough audience...
>>>
>>> What I meant to say was "PDP-8s had 12-bit words and IIRC some notion of
>>> 6-bit bytes.  PDP-11s had 8-bit bytes in 16-bit words"
>>>
>>> Somewhere between brain and fingers my neural network must have dropped
>>> a packet......
>>>
>>> /Jack
>>>
>>>
>>> On 10/09/2016 12:20 PM, Scott O. Bradner wrote:
>>>>
>>>>> On Oct 9, 2016, at 2:36 PM, Jack Haverty <jack at 3kitty.org> wrote:
>>>>>
>>>>> Hi Noel,
>>>>>
>>>>> You're right, I should have said 32KW....but I wonder how many people
>>>>> today would know what "KW" means?  I suspect many would think it
>>>>> referred to the power that our ancient monsters consumed...actually
>>>>> probably not far off for the bigger machines that consumed many square
>>>>> feet of lab space!
>>>>>
>>>>> The other aspect of the "Stone Age" that may not be remembered today is
>>>>> that a "byte" was not yet very well-defined back then.  PDP-8s had 8-bit
>>>>> bytes in 16-bit words.  
>>>>
>>>>
>>>> PDP-8s were 12 bit words
>>>>
>>>> PDP-1, 7, 9, 15 were 18 bit words
>>>>
>>>> PDP-11 were 16 bit words
>>>>
>>>> PDD 6, 10 were 36 bit words
>>>>
>>>> Scott
>>>>
>>>>> Other machines made different choices.  The
>>>>> PDP-10 was agnostic -- the instruction set allowed the programmer to
>>>>> specify whatever byte size they liked.  So a "byte" only made sense in
>>>>> the context of a specific machine.
>>>>>
>>>>> Today of course we all know that a byte is 8 bits.  Period.  Perhaps
>>>>> some historian can figure out exactly when that happened.....
>>>>>
>>>>> Fun times...
>>>>> /Jack
>>>>>
>>>>> On 10/09/2016 10:21 AM, Noel Chiappa wrote:
>>>>>> A few notes/corrections:
>>>>>>
>>>>>>> The /40 design utilized a single address space for instructions and
>>>>>>> data, so everything had to fit in 32KB of memory (yes K, not M or G).
>>>>>>
>>>>>> Err, that was 32KW, i.e. 64KB. But 8KB was the I/O page (device registers), so
>>>>>> only 56KB of memory - sort of, because V6 Unix used one 8KB page to map in
>>>>>> each process' kernel stack + other swappable per-process data, so really only
>>>>>> 48KB for all kernel code, data, disk buffers, etc.
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>>>>
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>