What's Your Favorite Processor on an FPGA?

On 4/23/2013 8:14 PM, John Larkin wrote:
> On Tue, 23 Apr 2013 19:45:07 -0400, rickman<gnuarm@gmail.com>  wrote:
>
>> On 4/23/2013 10:03 AM, John Larkin wrote:
>>>
>>> No, but it's mostly dead, as PCI will soon be. Intel busses only last a few
>>> years each.
>>
>> A *few* years?  PCI has been around for 20 years!
>
> But mobos seldom have PCI slots any more. It's all PCIe now. And
> Thunderbolt will displace PCIe.
>
> Motherboard slots are going away. Hell, motherboards are going away!

Sure, for that matter PCs are going away for the mainstream.  In 10 
years it will literally be like working on the Enterprise... the space 
ship Enterprise.  Everyone will be using tablets and pads, there just 
won't be a need for the traditional PC except for specialties... like 
PCB layout, lol

There won't be any busses really.  It will all be wireless.  Maybe it 
will all be powered by a Tesla type power source too. lol

That doesn't change the fact that PCI was mainstream for well over a 
decade, more like 15 years!

BTW, are you capable of learning?  Or have you reached your learning 
capacity?

-- 

Rick

langwadt@fonz.dk wrote:
> On Apr 22, 5:16 pm, John Larkin
> <jjlar...@highNOTlandTHIStechnologyPART.com>  wrote:
>> On 22 Apr 2013 14:57:24 GMT, Allan Herriman<allanherri...@hotmail.com>  wrote:
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>> On Mon, 22 Apr 2013 07:09:40 -0700, John Larkin wrote:
>>
>>>> On 22 Apr 2013 12:59:27 GMT, Allan Herriman<allanherri...@hotmail.com>
>>>> wrote:
>>
>>>>> On Sun, 21 Apr 2013 09:05:49 -0700, John Larkin wrote:
>>
>>>>>> The annoying thing is the CPU-to-FPGA interface. It takes a lot of
>>>>>> FPGA pins and it tends to be async and slow. It would be great to have
>>>>>> an industry-standard LVDS-type fast serial interface, with hooks like
>>>>>> shared memory, but transparent and easy to use.
>>
>>>>> You've just described PCI Express.
>>
>>>> No. PCIe is insanely complex and has horrible latency. It takes
>>>> something like 2 microseconds to do an 8-bit read over gen1 4-lane PCIe.
>>>> It was designed for throughput, not latency.
>>
>>> I agree about it being designed for throughput, not latency.  However,
>>> with a fairly simple design, we can do 32 bit non-bursting reads or
>>> writes in about 350ns over a single lane of gen 1 through 1 layer of
>>> switching.  I suspect there's some problem with your implementation
>>> (unless your 2 microsecond figure was just hyperbole).
>>
>> Writes are relatively fast, ballpark 350 ns gen1/4lane. Reads are slow, around 2
>> us. That's from an x86 CPU into the PCIe hard core of an Altera FPGA, cabled
>> PCIe. A read requires two serial packets so is over twice the time of a write.
>>
>> A random read or write from an embedded CPU, to, say, a DPM in an FPGA, really
>> should take tens of nanoseconds. We do parallel ARM-FPGA transfers with a klunky
>> async parallel interface in 100 ns or so, but it takes a lot of pins.
>>
>>  From an x86 (not that we'd ever use an Intel chip in an embedded app) we haven't
>> found any way to move more than 32 bits in a non-DMA PCIe read/write, even on a
>> 64-bit CPU that has a few 128-bit MOVE opcodes.
>>
>>
>>
>>>> We've done three PCIe projects so far, and it's the opposite of
>>>> "transparent and easy to use." The PCIe spec reads like the tax code and
>>>> Obamacare combined.
>>
>>> I found the spec clear.  It's rather large though, and a text book serves
>>> as more friendly introduction to the subject than the spec itself.
>>
>>> One of my co-workers was confused by the way addresses come most
>>> significant octet first, whilst the data come least significant octet
>>> first.  It makes sense on a little endian machine, once you get over the
>>> WTF.
>>
>> Little-endian is evil, another legacy if Intel's clumsiness.
>>
>
> why is it any more or less evil than big endian?
>
> -Lasse
   Just give me his feather headband..

Nico Coesel wrote:
> John Larkin<jjlarkin@highNOTlandTHIStechnologyPART.com>  wrote:
>
>> On Sun, 21 Apr 2013 08:23:37 -0500, Vladimir Vassilevsky<nospam@nowhere.com>
>> wrote:
>>
>>> On 4/20/2013 5:42 PM, rickman wrote:
>>>> I have been working on designs of processors for FPGAs for quite a
>>>> while.  I have looked at the uBlaze, the picoBlaze, the NIOS, two from
>>>> Lattice and any number of open source processors.  Many of the open
>>>> source designs were stack processors since they tend to be small and
>>>> efficient in an FPGA.  J1 is one I had pretty much missed until lately.
>>>>    It is fast and small and looks like it wasn't too hard to design
>>>> (although looks may be deceptive), I'm impressed.  There is also the b16
>>>> from Bernd Paysan, the uCore, the ZPU and many others.
>>>>
>>>> Lately I have been looking at a hybrid approach which combines features
>>>> of addressing registers in order to access parameters of a stack CPU. It
>>>> looks interesting.
>>>>
>>>> Anyone else here doing processor designs on FPGAs?
>>>>
>>>
>>> Soft core is fun thing to do, but otherwise I see no use.
>>> Except for very few special applications, standalone processor is better
>>> then FPGA soft core in every point, especially the price.
>
> Most entry level scopes consist of an FPGA running a soft processor.
>
>> The annoying thing is the CPU-to-FPGA interface. It takes a lot of FPGA pins and
>> it tends to be async and slow. It would be great to have an industry-standard
>> LVDS-type fast serial interface, with hooks like shared memory, but transparent
>> and easy to use.
>
> You mean PCI express? :-)
>
   What the hell is wrong with PARALLEL?
   You get the _whole_ byte/word/whatever each possible I/O cycle and do 
not have to wait 20+ cycles for preamble bits, 16 data bits, stop bits 
(maybe more for stupid "framing" because designer was too lazy to 
enforce assumptions that would speed things up).

On Wed, 24 Apr 2013 14:34:09 -0400, rickman <gnuarm@gmail.com> wrote:

>On 4/23/2013 8:14 PM, John Larkin wrote:
>> On Tue, 23 Apr 2013 19:45:07 -0400, rickman<gnuarm@gmail.com>  wrote:
>>
>>> On 4/23/2013 10:03 AM, John Larkin wrote:
>>>>
>>>> No, but it's mostly dead, as PCI will soon be. Intel busses only last a few
>>>> years each.
>>>
>>> A *few* years?  PCI has been around for 20 years!
>>
>> But mobos seldom have PCI slots any more. It's all PCIe now. And
>> Thunderbolt will displace PCIe.
>>
>> Motherboard slots are going away. Hell, motherboards are going away!
>
>Sure, for that matter PCs are going away for the mainstream.  In 10 
>years it will literally be like working on the Enterprise... the space 
>ship Enterprise.  Everyone will be using tablets and pads, there just 
>won't be a need for the traditional PC except for specialties... like 
>PCB layout, lol
>
>There won't be any busses really.  It will all be wireless.  Maybe it 
>will all be powered by a Tesla type power source too. lol
>
>That doesn't change the fact that PCI was mainstream for well over a 
>decade, more like 15 years!
>
>BTW, are you capable of learning?  Or have you reached your learning 
>capacity?

This week's project is to learn all about synchros, resolvers, control
transformers, and the many other related critters, and to figure out the
conventions, voltages, phases, and the trig for acquiring and simulating all of
that stuff. 

I did win a burger and a beer. I guessed that the GCC atan2 function would take
about 10 us on our ARM processor, and Rob bet it would take one. He wanted to
bet based on 5.5 as the cut point, but I suggested that the geometric mean was
more fair. Ok, it takes just about 4 us, so I won by about 800 ns.
Now he wants to hack the source code to eliminate some paths we don't need, like
the checks for infinity and NAN and such, and speed it up. That would be a lot
of work for a burger and a beer.

And I'm about to learn a lot about kilowatt bar lasers, preferably without
losing any important body parts.



-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

John Larkin wrote:
> 
> On Tue, 23 Apr 2013 22:38:23 -0400, "Michael A. Terrell"
> <mike.terrell@earthlink.net> wrote:
> 
> >
> >John Larkin wrote:
> >>
> >> On Tue, 23 Apr 2013 02:48:53 -0400, "Michael A. Terrell"
> >> <mike.terrell@earthlink.net> wrote:
> >>
> >> >
> >> >John Larkin wrote:
> >> >>
> >> >> On Mon, 22 Apr 2013 07:49:11 -0400, "Michael A. Terrell"
> >> >> <mike.terrell@earthlink.net> wrote:
> >> >>
> >> >> >
> >> >> >John Larkin wrote:
> >> >> >>
> >> >> >> DEC wrote operating systems (TOPS10, VMS, RSTS) that ran for months between
> >> >> >> power failures, time-sharing multiple, sometimes hostile, users. We are now in
> >> >> >> the dark ages of computing, overwhelmed by bloat and slop and complexity. No
> >> >> >> wonder people are buying tablets. DEC understood things that Intel and Microsoft
> >> >> >> never really got, like: don't execute data.
> >> >> >
> >> >> >
> >> >> >   I've had Win2K run over nine months, between power failures that
> >> >> >lasted longer than the UPS batteries.  DEC had more control over the
> >> >> >computers, and a tiny fraction of the number running Windows or Linux.
> >> >> >
> >> >> >
> >> >> >   If DEC was so damned good, why were they unable to survive?  Their
> >> >> >IBM 'clone' (Rainbow 100) was very overpriced, not compatible, and did a
> >> >> >very quick death spiral.  Admit it.  It was a dinosaur company with a
> >> >> >very tiny customer base.
> >> >>
> >> >> It was *the* minicomputer company and that changed the world.
> >> >
> >> >
> >> >   Really?  Could it have handled any modern application, let alone
> >> >dozens or hundreds of them at once.
> >>
> >> As I recall, Unix and C were invented for the PDP11. As was Arpanet and the
> >> Internet. The PDP8 was the first "personal" computer, a computer that one person
> >> could buy and use all by himself, to automate a lab experiment or (in my case)
> >> simulate a steamship power train. That changed everything.
> >>
> >> DECs RT11 OS was cloned to become CPM and Microsoft DOS, and lives on in the
> >> Windows command line.
> >
> >
> >   CP/M<>DOS and never was.  'Control Program for Microcomputers' was
> >written by Gary Kildall of Digital Research, Inc, and the later MP/M for
> >multiple users was written for the 8080 from scratch.  If that is a
> >clone, so is every other OS.
> >
> >
> >> What sort of computing system did you have in 1969? I had a PDP8 running Focal.
> >
> >
> >   Did you own it?
> 
> No, but my employer bought it for me; cost $12,800 with 4k 12-bit words of core
> and a teletype, when you could but a Chevy for a tenth of that. It was mine in
> the sense that I was the main, usually only, user. A couple of years later, 1972
> I think, we got one of the first PDP-11s. The PDP-11 was a wonderful
> architecture; it taught a lot of people, including me, how to think. x86 is a
> pig by comparison.


   Yet the PDP-11s have all been scrapped.  I scrapped a lot of them in
the early '90s.  Tractor trailer loads of off lease CAD systems.

On Thu, 25 Apr 2013 00:10:17 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

>
>John Larkin wrote:
>> 
>> On Tue, 23 Apr 2013 22:38:23 -0400, "Michael A. Terrell"
>> <mike.terrell@earthlink.net> wrote:
>> 
>> >
>> >John Larkin wrote:
>> >>
>> >> On Tue, 23 Apr 2013 02:48:53 -0400, "Michael A. Terrell"
>> >> <mike.terrell@earthlink.net> wrote:
>> >>
>> >> >
>> >> >John Larkin wrote:
>> >> >>
>> >> >> On Mon, 22 Apr 2013 07:49:11 -0400, "Michael A. Terrell"
>> >> >> <mike.terrell@earthlink.net> wrote:
>> >> >>
>> >> >> >
>> >> >> >John Larkin wrote:
>> >> >> >>
>> >> >> >> DEC wrote operating systems (TOPS10, VMS, RSTS) that ran for months between
>> >> >> >> power failures, time-sharing multiple, sometimes hostile, users. We are now in
>> >> >> >> the dark ages of computing, overwhelmed by bloat and slop and complexity. No
>> >> >> >> wonder people are buying tablets. DEC understood things that Intel and Microsoft
>> >> >> >> never really got, like: don't execute data.
>> >> >> >
>> >> >> >
>> >> >> >   I've had Win2K run over nine months, between power failures that
>> >> >> >lasted longer than the UPS batteries.  DEC had more control over the
>> >> >> >computers, and a tiny fraction of the number running Windows or Linux.
>> >> >> >
>> >> >> >
>> >> >> >   If DEC was so damned good, why were they unable to survive?  Their
>> >> >> >IBM 'clone' (Rainbow 100) was very overpriced, not compatible, and did a
>> >> >> >very quick death spiral.  Admit it.  It was a dinosaur company with a
>> >> >> >very tiny customer base.
>> >> >>
>> >> >> It was *the* minicomputer company and that changed the world.
>> >> >
>> >> >
>> >> >   Really?  Could it have handled any modern application, let alone
>> >> >dozens or hundreds of them at once.
>> >>
>> >> As I recall, Unix and C were invented for the PDP11. As was Arpanet and the
>> >> Internet. The PDP8 was the first "personal" computer, a computer that one person
>> >> could buy and use all by himself, to automate a lab experiment or (in my case)
>> >> simulate a steamship power train. That changed everything.
>> >>
>> >> DECs RT11 OS was cloned to become CPM and Microsoft DOS, and lives on in the
>> >> Windows command line.
>> >
>> >
>> >   CP/M<>DOS and never was.  'Control Program for Microcomputers' was
>> >written by Gary Kildall of Digital Research, Inc, and the later MP/M for
>> >multiple users was written for the 8080 from scratch.  If that is a
>> >clone, so is every other OS.
>> >
>> >
>> >> What sort of computing system did you have in 1969? I had a PDP8 running Focal.
>> >
>> >
>> >   Did you own it?
>> 
>> No, but my employer bought it for me; cost $12,800 with 4k 12-bit words of core
>> and a teletype, when you could but a Chevy for a tenth of that. It was mine in
>> the sense that I was the main, usually only, user. A couple of years later, 1972
>> I think, we got one of the first PDP-11s. The PDP-11 was a wonderful
>> architecture; it taught a lot of people, including me, how to think. x86 is a
>> pig by comparison.
>
>
>   Yet the PDP-11s have all been scrapped. 


Sure. There's not a lot of demand for fractional-mips computers with kilobyte
core memories. Lots of Univacs, Crays, GE, and IBM PC-XT computers have been
scrapped too.


-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

John Larkin wrote:
> 
> On Tue, 23 Apr 2013 22:40:51 -0400, "Michael A. Terrell"
> <mike.terrell@earthlink.net> wrote:
> 
> >
> >John Larkin wrote:
> >>
> >> On Tue, 23 Apr 2013 02:50:10 -0400, "Michael A. Terrell"
> >> <mike.terrell@earthlink.net> wrote:
> >>
> >> >
> >> >John Larkin wrote:
> >> >>
> >> >> On 22 Apr 2013 12:59:27 GMT, Allan Herriman <allanherriman@hotmail.com> wrote:
> >> >>
> >> >> >On Sun, 21 Apr 2013 09:05:49 -0700, John Larkin wrote:
> >> >> >
> >> >> >> The annoying thing is the CPU-to-FPGA interface. It takes a lot of FPGA
> >> >> >> pins and it tends to be async and slow. It would be great to have an
> >> >> >> industry-standard LVDS-type fast serial interface, with hooks like
> >> >> >> shared memory, but transparent and easy to use.
> >> >> >
> >> >> >You've just described PCI Express.
> >> >>
> >> >> No. PCIe is insanely complex and has horrible latency. It takes something like 2
> >> >> microseconds to do an 8-bit read over gen1 4-lane PCIe. It was designed for
> >> >> throughput, not latency.
> >> >>
> >> >> We've done three PCIe projects so far, and it's the opposite of "transparent and
> >> >> easy to use." The PCIe spec reads like the tax code and Obamacare combined.
> >> >>
> >> >> Next up is Thunderbolt, probably worse.
> >> >
> >> >
> >> >   Have you ever worked with PCI-X?
> >>
> >> No, but it's mostly dead, as PCI will soon be. Intel busses only last a few
> >> years each.
> >
> >
> >   It's alive & well in real servers for their RAID controllers and
> >Ethernet or FC ports.  I've never seen it used in a computer that sold
> >for under $3K.
> 
> Do current Intel chip sets support PCI-X? Or even PCI?



   Ask Intel.

   Dell still sells a bunch of expensive PCI-X cards, and they are quick
to drop items like that if the market drops.  Some of the cards are
$1800.

   A lot of external drive arrays for server farms use Fiber Channel
PCI-X interface cards.

Michael A. Terrell wrote:
>
> John Larkin wrote:
>>
>> On Tue, 23 Apr 2013 22:38:23 -0400, "Michael A. Terrell"
>> <mike.terrell@earthlink.net>  wrote:
>>
>>>
>>> John Larkin wrote:
>>>>
>>>> On Tue, 23 Apr 2013 02:48:53 -0400, "Michael A. Terrell"
>>>> <mike.terrell@earthlink.net>  wrote:
>>>>
>>>>>
>>>>> John Larkin wrote:
>>>>>>
>>>>>> On Mon, 22 Apr 2013 07:49:11 -0400, "Michael A. Terrell"
>>>>>> <mike.terrell@earthlink.net>  wrote:
>>>>>>
>>>>>>>
>>>>>>> John Larkin wrote:
>>>>>>>>
>>>>>>>> DEC wrote operating systems (TOPS10, VMS, RSTS) that ran for months between
>>>>>>>> power failures, time-sharing multiple, sometimes hostile, users. We are now in
>>>>>>>> the dark ages of computing, overwhelmed by bloat and slop and complexity. No
>>>>>>>> wonder people are buying tablets. DEC understood things that Intel and Microsoft
>>>>>>>> never really got, like: don't execute data.
>>>>>>>
>>>>>>>
>>>>>>>    I've had Win2K run over nine months, between power failures that
>>>>>>> lasted longer than the UPS batteries.  DEC had more control over the
>>>>>>> computers, and a tiny fraction of the number running Windows or Linux.
>>>>>>>
>>>>>>>
>>>>>>>    If DEC was so damned good, why were they unable to survive?  Their
>>>>>>> IBM 'clone' (Rainbow 100) was very overpriced, not compatible, and did a
>>>>>>> very quick death spiral.  Admit it.  It was a dinosaur company with a
>>>>>>> very tiny customer base.
>>>>>>
>>>>>> It was *the* minicomputer company and that changed the world.
>>>>>
>>>>>
>>>>>    Really?  Could it have handled any modern application, let alone
>>>>> dozens or hundreds of them at once.
>>>>
>>>> As I recall, Unix and C were invented for the PDP11. As was Arpanet and the
>>>> Internet. The PDP8 was the first "personal" computer, a computer that one person
>>>> could buy and use all by himself, to automate a lab experiment or (in my case)
>>>> simulate a steamship power train. That changed everything.
>>>>
>>>> DECs RT11 OS was cloned to become CPM and Microsoft DOS, and lives on in the
>>>> Windows command line.
>>>
>>>
>>>    CP/M<>DOS and never was.  'Control Program for Microcomputers' was
>>> written by Gary Kildall of Digital Research, Inc, and the later MP/M for
>>> multiple users was written for the 8080 from scratch.  If that is a
>>> clone, so is every other OS.
>>>
>>>
>>>> What sort of computing system did you have in 1969? I had a PDP8 running Focal.
>>>
>>>
>>>    Did you own it?
>>
>> No, but my employer bought it for me; cost $12,800 with 4k 12-bit words of core
>> and a teletype, when you could but a Chevy for a tenth of that. It was mine in
>> the sense that I was the main, usually only, user. A couple of years later, 1972
>> I think, we got one of the first PDP-11s. The PDP-11 was a wonderful
>> architecture; it taught a lot of people, including me, how to think. x86 is a
>> pig by comparison.
>
>
>     Yet the PDP-11s have all been scrapped.  I scrapped a lot of them in
> the early '90s.  Tractor trailer loads of off lease CAD systems.
   Yeah, for the PDP-11, designing specialized interface boards and 
programming for them was very nice and straight-forward.

On Wed, 24 Apr 2013 13:15:12 -0800, Robert Baer
<robertbaer@localnet.com> wrote:

>> Most entry level scopes consist of an FPGA running a soft processor.
>>
>>> The annoying thing is the CPU-to-FPGA interface. It takes a lot of FPGA pins and
>>> it tends to be async and slow. It would be great to have an industry-standard
>>> LVDS-type fast serial interface, with hooks like shared memory, but transparent
>>> and easy to use.
>>
>> You mean PCI express? :-)
>>
>   What the hell is wrong with PARALLEL?
>   You get the _whole_ byte/word/whatever each possible I/O cycle and do 
>not have to wait 20+ cycles for preamble bits, 16 data bits, stop bits 
>(maybe more for stupid "framing" because designer was too lazy to 
>enforce assumptions that would speed things up).

The real problem with parallel channels is that the length
(propagation delay) of each channel must be the same. 

In the 1970's with 1/2 inch magnetic tapes, the 1600 BPI tapes were
much easier to read, since each channel was self-clocked.

However, in order to read 800 BPI (non-self-clocked)  tapes written on
a foreign tape drive, you had to use a screw driver to adjust the read
head azimuth angle, to compensate for the skew at different bit
channels.

On Wed, 24 Apr 2013 22:33:32 -0800, Robert Baer
<robertbaer@localnet.com> wrote:

>Michael A. Terrell wrote:
>>
>> John Larkin wrote:
>>>
>>> On Tue, 23 Apr 2013 22:38:23 -0400, "Michael A. Terrell"
>>> <mike.terrell@earthlink.net>  wrote:
>>>
>>>>
>>>> John Larkin wrote:
>>>>>
>>>>> On Tue, 23 Apr 2013 02:48:53 -0400, "Michael A. Terrell"
>>>>> <mike.terrell@earthlink.net>  wrote:
>>>>>
>>>>>>
>>>>>> John Larkin wrote:
>>>>>>>
>>>>>>> On Mon, 22 Apr 2013 07:49:11 -0400, "Michael A. Terrell"
>>>>>>> <mike.terrell@earthlink.net>  wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> John Larkin wrote:
>>>>>>>>>
>>>>>>>>> DEC wrote operating systems (TOPS10, VMS, RSTS) that ran for months between
>>>>>>>>> power failures, time-sharing multiple, sometimes hostile, users. We are now in
>>>>>>>>> the dark ages of computing, overwhelmed by bloat and slop and complexity. No
>>>>>>>>> wonder people are buying tablets. DEC understood things that Intel and Microsoft
>>>>>>>>> never really got, like: don't execute data.
>>>>>>>>
>>>>>>>>
>>>>>>>>    I've had Win2K run over nine months, between power failures that
>>>>>>>> lasted longer than the UPS batteries.  DEC had more control over the
>>>>>>>> computers, and a tiny fraction of the number running Windows or Linux.
>>>>>>>>
>>>>>>>>
>>>>>>>>    If DEC was so damned good, why were they unable to survive?  Their
>>>>>>>> IBM 'clone' (Rainbow 100) was very overpriced, not compatible, and did a
>>>>>>>> very quick death spiral.  Admit it.  It was a dinosaur company with a
>>>>>>>> very tiny customer base.
>>>>>>>
>>>>>>> It was *the* minicomputer company and that changed the world.
>>>>>>
>>>>>>
>>>>>>    Really?  Could it have handled any modern application, let alone
>>>>>> dozens or hundreds of them at once.
>>>>>
>>>>> As I recall, Unix and C were invented for the PDP11. As was Arpanet and the
>>>>> Internet. The PDP8 was the first "personal" computer, a computer that one person
>>>>> could buy and use all by himself, to automate a lab experiment or (in my case)
>>>>> simulate a steamship power train. That changed everything.
>>>>>
>>>>> DECs RT11 OS was cloned to become CPM and Microsoft DOS, and lives on in the
>>>>> Windows command line.
>>>>
>>>>
>>>>    CP/M<>DOS and never was.  'Control Program for Microcomputers' was
>>>> written by Gary Kildall of Digital Research, Inc, and the later MP/M for
>>>> multiple users was written for the 8080 from scratch.  If that is a
>>>> clone, so is every other OS.
>>>>
>>>>
>>>>> What sort of computing system did you have in 1969? I had a PDP8 running Focal.
>>>>
>>>>
>>>>    Did you own it?
>>>
>>> No, but my employer bought it for me; cost $12,800 with 4k 12-bit words of core
>>> and a teletype, when you could but a Chevy for a tenth of that. It was mine in
>>> the sense that I was the main, usually only, user. A couple of years later, 1972
>>> I think, we got one of the first PDP-11s. The PDP-11 was a wonderful
>>> architecture; it taught a lot of people, including me, how to think. x86 is a
>>> pig by comparison.
>>
>>
>>     Yet the PDP-11s have all been scrapped.  I scrapped a lot of them in
>> the early '90s.  Tractor trailer loads of off lease CAD systems.
>   Yeah, for the PDP-11, designing specialized interface boards and 
>programming for them was very nice and straight-forward.

The 11 had no i/o instructions, which was cool. Devices were memory
mapped, so no opcodes were wasted on klunky IN and OUT instructions,
and any memory opcode could operate on i/o, too. 68K worked like that,
too. The 68K was just a better PDP-11.

The PDP-11 was programmed in octal, and with a little practice you
could assemble instruction in your head and map them directly into
octal. I can still do some.

MOVB (r1)+, R5  is (I think) 112105 octal.




-- 

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation