[fpc-other] [fpc-pascal] Quick Modern Object Pascal Introduction, for Programmers

[Paul Breneman]

On 06/21/2016 07:02 PM, brian wrote:
> On Mon, 20 Jun 2016 18:53:12 +0000, Mark Morgan Lloyd wrote:
>
>> Luca Olivetti wrote:
>>> El 20/06/16 a les 11:44, Mark Morgan Lloyd ha escrit:
>>>
>>>> A private online service I use has somebody who still bears the scars of
>>>> Olivetti attempting to write an operating system in (strict, unexpanded)
>>>> Pascal.
>>>
>>> Oh, the memories (and, no, I'm not related). My first job was in one of
>>> Olivetti's factories where they used such a system for production
>>> control (they ate their own dog food).
>>> I was programming the PLC (well, part of it) and it had to keep in
>>> memory two hours worth of planning since that was the time the computer
>>> needed to reboot when it crashed ;-)
>>>
>>> I doubt it was plain pascal though: according to this page
>>>
>>> http://www.storiaolivetti.it/percorso.asp?idPercorso=564
>>>
>>> it was concurrent pascal
>>>
>>> https://en.wikipedia.org/wiki/Concurrent_Pascal
>>>
>>> (even if I'm not sure the wikipedia page refers to the same thing).
>>
>> I think he said it was mid-70s, but I got the impression that it was
>> very much ISO-standard Pascal and it didn't have facilities such as
>> assembler interfacing. On the other hand I think Concurrent Pascal was
>> one of Brinch Hansen's earlier attempts, and like Pascal itself it might
>> have taken a couple of iterations to get right.
>>
>> The bottom line was that it was an unmitigated disaster :-)
>
> There was more than one dog's breakfast of a Pascal compiler around in
> those days, My own favourite candidate was Whitesmith's Pascal for the
> PDP-11. Debugging had to be done in octal from Macro-11 listings, and
> Whitesmith's produced some memorably large and inefficient code. I
> have vague memories (35 years later!) of successive increment and
> decrement instructions *on the same register*. When you're trying to
> shoehorn everything into 32KB, albeit with overlays, that sort of
> thing MATTERS. :(
>
> It was only after monitoring the compilation process via RMD and then
> doing a bit of RTFM that we realised what was happening - Whitesmith's
> Pascal, at least of that era, was a translator rather than a compiler.
> It was translating the Pascal code to C and then invoking Whitesmith's
> C compiler.
>
> We played with it for a few days, then moved on to Oregon (OMSI)
> Pascal and never went back. I believe OMSI eventually became the basis
> of RSX-Pascal, which didn't exist at the point we were looking at
> compilers.
>
> Brian.

Speaking of PDP-11, I did assembler on it for 14 years then ported the 
entire thing to Turbo Pascal (thankfully *no* octal any more):
   http://brenemanlabs.com/MachOne5.htm
For real-time video machine control in the PC folks before me had to use 
complex intelligent serial port cards.  But the 16550 UARTS had come out 
and I used them as the video tape machine commands all fit in the 16 
byte FIFO.  So I had 50,000 lines of all pascal code (no assembler) with 
a third of it running 30 times a second (frame rate) in an interrupt 
routine with no interrupts on 16 serial ports.

Some PDP-11s are still being used:
http://www.theregister.co.uk/2013/06/19/nuke_plants_to_keep_pdp11_until_2050/

Regards,
Paul
www.ControlPascal.com