Megalextoria
Retro computing and gaming, sci-fi books, tv and movies and other geeky stuff.

Home » Digital Archaeology » Computer Arcana » Computer Folklore » The power of the original PDP11 (20, 10) but for only tuppence!
Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend 
Switch to threaded view of this topic Create a new topic Submit Reply
The power of the original PDP11 (20, 10) but for only tuppence! [message #287500] Fri, 10 April 2015 07:52 Go to next message
gareth is currently offline  gareth
Messages: 598
Registered: June 2012
Karma: 0
Senior Member
http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf
Re: The power of the original PDP11 (20, 10) but for only tuppence! [message #287501 is a reply to message #287500] Fri, 10 April 2015 09:30 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: Johnny Billquist

On 2015-04-10 13:52, gareth wrote:
> http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf

Oh, c'mon. You can't just go around and claim that any 16-bit CPU is a
PDP-11...

And as far as "power" goes. That depends on how you measure things.
The Microchip have a larger address space than any PDP-11, but on the
other hand, it does not have an MMU, as far as I can tell... Nor FP
hardware.

Johnny
Re: The power of the original PDP11 (20, 10) but for only tuppence! [message #287502 is a reply to message #287501] Fri, 10 April 2015 09:43 Go to previous messageGo to next message
bill is currently offline  bill
Messages: 165
Registered: December 2011
Karma: 0
Senior Member
In article <mg8j8r$r3a$1@iltempo.update.uu.se>,
Johnny Billquist <bqt@softjar.se> writes:
> On 2015-04-10 13:52, gareth wrote:
>> http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf
>
> Oh, c'mon. You can't just go around and claim that any 16-bit CPU is a
> PDP-11...
>
> And as far as "power" goes. That depends on how you measure things.
> The Microchip have a larger address space than any PDP-11, but on the
> other hand, it does not have an MMU, as far as I can tell... Nor FP
> hardware.
>

I kind of got the idea he was hinting at Microcoding a PDP-11 on top
of one of those PICs. Pretty sure that has already been done. Once
I retire (again) this June I hope to learn VHDL and do some playing
with stuff like that on the development kits I have. Still may get
the chance to try out some of the extensions I thought would have
worked well on the PDP-11.

Oh yeah, and being as I have given up on any hope of the PDP-11 OSes
(in particular RSTS) ever being released I think I will take a serious
look at writing a clone. :-)

bill

--
Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves
billg999@cs.scranton.edu | and a sheep voting on what's for dinner.
University of Scranton |
Scranton, Pennsylvania | #include <std.disclaimer.h>
Re: The power of the original PDP11 (20, 10) but for only tuppence! [message #287503 is a reply to message #287501] Fri, 10 April 2015 10:00 Go to previous messageGo to next message
gareth is currently offline  gareth
Messages: 598
Registered: June 2012
Karma: 0
Senior Member
"Johnny Billquist" <bqt@softjar.se> wrote in message
news:mg8j8r$r3a$1@Iltempo.Update.UU.SE...
> On 2015-04-10 13:52, gareth wrote:
>> http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf
>
> Oh, c'mon. You can't just go around and claim that any 16-bit CPU is a
> PDP-11...
>
> And as far as "power" goes. That depends on how you measure things.
> The Microchip have a larger address space than any PDP-11, but on the
> other hand, it does not have an MMU, as far as I can tell... Nor FP
> hardware.

Nor did the original PDP11/20 and /10, as per the title.
Re: The power of the original PDP11 (20, 10) but for only tuppence! [message #287749 is a reply to message #287501] Tue, 14 April 2015 19:53 Go to previous messageGo to next message
Walter Bushell is currently offline  Walter Bushell
Messages: 1834
Registered: December 2011
Karma: 0
Senior Member
In article <mg8j8r$r3a$1@Iltempo.Update.UU.SE>,
Johnny Billquist <bqt@softjar.se> wrote:

> On 2015-04-10 13:52, gareth wrote:
>> http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf
>
> Oh, c'mon. You can't just go around and claim that any 16-bit CPU is a
> PDP-11...
>
> And as far as "power" goes. That depends on how you measure things.
> The Microchip have a larger address space than any PDP-11, but on the
> other hand, it does not have an MMU, as far as I can tell... Nor FP
> hardware.
>
> Johnny

Well FP hardware is a mere matter of speed. Some chips without FP
hardware are faster at FP than some with. Example, 68040 without FP
was faster than the predecessor 68030 with FP hardware.

--
Never attribute to stupidity that which can be explained by greed. Me.
Re: The power of the original PDP11 (20, 10) but for only tuppence! [message #287933 is a reply to message #287749] Thu, 16 April 2015 09:38 Go to previous message
Lawrence Statton is currently offline  Lawrence Statton
Messages: 326
Registered: May 2013
Karma: 0
Senior Member
Walter Bushell <proto@panix.com> writes:

> In article <mg8j8r$r3a$1@Iltempo.Update.UU.SE>,
> Johnny Billquist <bqt@softjar.se> wrote:
>
>> On 2015-04-10 13:52, gareth wrote:
>>> http://ww1.microchip.com/downloads/en/DeviceDoc/70157D.pdf
>>
>> Oh, c'mon. You can't just go around and claim that any 16-bit CPU is a
>> PDP-11...
>>
>> And as far as "power" goes. That depends on how you measure things.
>> The Microchip have a larger address space than any PDP-11, but on the
>> other hand, it does not have an MMU, as far as I can tell... Nor FP
>> hardware.
>>
>> Johnny
>
> Well FP hardware is a mere matter of speed. Some chips without FP
> hardware are faster at FP than some with. Example, 68040 without FP
> was faster than the predecessor 68030 with FP hardware.

Yeah, but part of that was the spectacular cycle-count for martialling
the CPU state onto the stack for the coprocessor "interrupt" ... Even on
the straight 68000, an A-line or F-line trap/rti had something like 30
cycles of overhead, and the larger (more CPU state) chips only got worse
and worse.
  Switch to threaded view of this topic Create a new topic Submit Reply
Previous Topic: Next FCUG meeting - Sunday, April 19
Next Topic: DEBE - card alternative
Goto Forum:
  

-=] Back to Top [=-
[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Fri Mar 29 11:05:19 EDT 2024

Total time taken to generate the page: 0.07886 seconds