[Simh] smallest pdp-11 that can run TECO and sockets(*)?

[Johnny Billquist]

Seems the 11/05 was slower than the 11/03 after all, even if not by 
much. :-)

See http://pages.cpsc.ucalgary.ca/~dsb/PDP11/Family.html

So, an 11/05 or 11/10 it is, if you want the slowest PDP-11.
Now, how about writing the TECO macro (not you, Davis), to actually do 
the web server dance?

	Johnny

On 2012-07-07 19:09, Johnny Billquist wrote:
> I should point out that the LSI-11 does not have EIS in the basic CPU.
> It's an option you can add, which have both EIS and FIS (the KEV-11,
> horrible :-) ).
> The LSI-11 is also 16-bit addresses only.
>
> I tried finding any information about the speed of the thing, but
> failed. But I think it is actually slower than the 11/05...
>
> Anyway, unless the OP actually aim to find a real 11/03, I fail to see
> the point here. An emulated machine will not perform or behave the same
> from a time point of view anyway, and since I've already pointed out
> that RT-11 will run on any PDP-11, and TECO runs under RT-11, any
> machine running RT-11 is essentially equivalent to the "smallest"
> (slowest) PDP-11 from a coding point of view.
>
> What is left is actually writing the code, something that seems to get
> much less attention...
>
>      Johnny
>
> On 2012-07-07 15:33, Davis Johnson wrote:
>> I would have to concur. I have a physical 11/05. The 11/05 (same CPU as
>> the 11/10) and it is nowhere near as capable as an 11/03. For a while
>> there DEC had a tendency to release two new machines at a time. One
>> would out perform the previous flagship processor, probably not costing
>> too much more. The other would be comparable with the previous flagship
>> processor but at a lower cost. The 11/05 was the similar capability
>> lower cost follow on to the 11/20.
>>
>> Comparing the 11/05 is slower than the 11/03 and lacking a bunch of
>> useful instructions. The 11/05 is totally devoid of any memory
>> management - 64K address space is all you get.
>>
>> You could not configure 64K, of course because of the reserved address
>> space. Mine has 32K, which I suppose is a typical large configuration.
>> Core memory was expensive. I suppose one could have added a 16K board
>> and had 48K but justifying the expense would have been difficult.
>>
>> On 7/7/2012 3:14 AM, Göran Åhling wrote:
>>> Well, I'd used the word "Weakest" to describe this aspect of a
>>> computer...
>>>
>>> Without reading any PDP-11 architecture handbook (today), I'd like to
>>> claim the initial design, the 11/20, to have the weakest architecture
>>> within the PDP-11 family, it was released in 1970.
>>>
>>> Just as all (almost) PDP:s the customer would order a CPU, and
>>> separately order as much or little of memory that was regarded
>>> "neccesary" for every task... 11/20 had a max. of 56 kB (28 kW), as
>>> the design has 16 bits of adressing (=64 kB), but 8 kB are reserved
>>> for I/O devices.
>>>
>>> Exactely how little memory that would be enough to run an OS, Teco and
>>> an async port, I can't judge, but running an emulator, like SIMH,
>>> would alow for testing of this. The 11/20 was sold along with core
>>> memory, so a fair core memory card size for the minimum system would
>>> be elegant...
>>>
>>> The instruction set of a PDP-11 was slightly extended with EIS for
>>> modells comming just a few years later,  as several options (floating
>>> point support, commersial calculations support,  memory management for
>>> 18 or 22 bits of address-space...)
>>>
>>> But, as Johnny says, the LSI-11, aka PDP11-03, beeing the first
>>> LSI-design from DEC, released in 1975 with the new LSI-bus (aka Q-bus)
>>> is always remembered as the slowest PDP of all times, even though the
>>> architecture might be slightly improved over 11/20!
>>>
>>> If you would like a running real physical system, the 11/03 would by
>>> far be the easier to get hold of, get running, and keep running. The
>>> 11/20 would typically need 2 pcs of 19" wide, 72" high racks... For
>>> emulation, this is however not an issue!
>>>
>>> /Göran
>>>
>>> On 2012-07-06 21:04, Richard wrote:
>>>> When I say "small", I'm referring to computational capacity, not
>>>> physical dimensions.
>>>
>>>
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>>>
>>>
>>>
>>
>>
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>


-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol