[Simh] Various

[Timothe Litt]

On 13-Feb-20 20:57, Johnny Billquist wrote:
> On 2020-02-14 01:35, Timothe Litt wrote:
>> On 13-Feb-20 19:21, Johnny Billquist wrote:
>>> On 2020-02-13 17:42, Clem Cole wrote:
>>>>
>>>>
>>>> On Thu, Feb 13, 2020 at 11:38 AM Clem Cole <clemc at ccc.com
>>>> <mailto:clemc at ccc.com>> wrote:
>>>>
>>>>     I think I saw a card read/punch only once on a PDP-6 IIRC, but it
>>>>     might have been a KA10.   I don't think I ever saw one on a
>>>> PDP-8/11
>>>>     or Vaxen.
>>>>
>>>> The more I think about it, there must have been one or two in the
>>>> mill or the machine room in MRO, but I just can not picture them.
>>>
>>> As far as I know, there was no punch for the PDP-8 or PDP-11.
>>> However, there were readers.
>>>
>>> And the PDP-11 reader controller sat on the Unibus, so it would not
>>> be hard to get it working on a VAX either. If that was officially
>>> supported or not I don't know, though.
>>>
>>> There were a bunch of PDP-11 Unibus peripherals that was never
>>> supported on a VAX. DECtape comes to mind, as well as RK05.
>>>
>>>   Johnny
>>>
>>
>> See my previous note.
>
> Came to yours later...
>
>> The punches you mention do exist, as do others (Not particularly
>> common or popular):
>>
>>   * PDP-11: CP11-UP Punch interface for Univac 1710 Card RDR/PUNCH
>
> Was that a CSS product perhaps? Even looking at the PDP-11 Peripherals
> handbook from 1976 don't mention it. There is only CM11, CR11 and
> CD11. All three are card reader only.

Special Systems, California. Responsible design engineer: Bob Edwards

Don't read anything into "Special Systems" - CSS just means "low volume"
- CSS would sell to anyone, though if a customer's request seemed
unique, the first (sometimes only) customer would pretty much pay the
NRE.  "Low volume" is relative - in the late 80s, line printers were CSS
products.

Can't say much about the CP11's volume - I only saw one.  I expect it
was low.

>
> Haven't manage to find anything on bitsavers yet, but there are a
> bunch of places to search, so I might just have missed it.
>
>> Card readers were sold and supported on all systems thru VAX.
>
> Thanks for clarifying that for me. I wasn't at all sure about the VAX.
>
>> Someone wrote a DECtape driver for VAX - I think Stan R., though it
>> wasn't supported.  DECtape controllers are odd devices - the TD10 is
>> reasonably smart, but the others put realtime constraints on the
>> drivers that could be hard to meet.  Anyhow, by the time the VAX came
>> out, TU58 and Floppies were cheaper and denser media.
>
> I actually do remember seeing it. Fun thing. :-)
>
>> There was also an unsupported DECtape driver for TOPS-20.
>
> KLs with DECtape was always only Tops-10?

Yup.

TOPS-20 had no official support for any IO bus device - except the AN20
(ARPAnet/IMP interface).  Except in that case, the DIA/DIB20 was
difficult to get on the 20 - it was standard on the 10.

However, several drivers for IOB devices existed.  Including the card
reader/punch.

The issue was simply that the IOB had been superseded by MASSBUS (for
DMA devices - disk, tape) - the DF10 channels were expensive in $ and in
memory ports.  For most unit record & Comm, cheaper and less overhead to
hang on the PDP-11 front end.  Unibus, and the drivers made the devices
smarter (and cheaper).  E.g. The 11 handled DMA, modem control, even
broadcast messaging.  And card images.  IOB card readers interrupt the
-10 for every column.  Even with BLKI in the interrupt locations, this
was annoying.  A typical IOB controller would be several rows of
modules, plus power and cooling.  Just the IOB paddle cards used more
backplane space than a Unibus SPC slot.

DECtape, the TD10, is an IOB (but not DMA) device.  Thus, no support. 
Customers who screamed loudly enough and were migrating from TOPS-10
could make it work- at the price of a DIB20 (a full cabinet) and a
TOPS-20 source kit.  When they heard the prices, most swallowed hard and
moved their data to disk or 9-Track.  The problem, of course, is that at
the time there was no replacement "personal media" on the -20 -- the FE
floppies (RX01) were not accessible to the OS, and there was no TU58
(even un-)support on TOPS20.

Both university and engineering shops liked personal media - mostly to
reduce demand for and clutter on expensive disk space.  But TOPS-20
management knew better.

>
>   Johnny
>
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