[cctalk] Re: Random items on Pascal #3

[Mark GREEN via cctalk]

 It was a loop hole in the strong typing of Pascal, not the operating system 
itself.  You could set up a record structure that mirrored the communications 
area and then map this to location zero.  This was important for Pascal since 
it had no library mechanism, it was essentially a compile and go system.  The 
run time was tied to the particular version of the compiler, if the run time 
was updated you had to update the tables in the compiler.  This was somewhat 
similar to the run Fortran compiler, which also avoided using the loader.  The 
loader was a wonderful piece of software, but it was expensive, so for teaching 
programming it was avoided at all cost.  I wrote a relational database system 
in Pascal for the CDC 6000 using this approach for the low level I/O routines.  
There were some wonderful things that you could do through the PPU programs.
If you were using the FTN compiler for Fortran you could do all of this in 
COMPASS, but for Pascal that wasn't an option.  One of the fun things you could 
do is having multiple I/O operations occurring at the same time.  A fun game 
was to issue a read and write on the same memory location and see when they 
passed each other.
On Thursday, May 16, 2024 at 04:04:05 a.m. EDT, Tom Hunter via cctalk 
 wrote:  
 
 I assume you refer to the "case ... of" construct in PASCAL record types
which allowed you to arbitrarily "cast" - to use a C term - variables to
any type you wanted and could be (ab)used to assign integers to pointers.

The ability to call PP programs via RA+1 calls was not a loop hole, but a
design feature of the CYBER/6600 operating systems like COS, KRONOS and
NOS. It simply involved writing to the word in location 1 (RA+1) relative
to the start of the segment of memory assigned to your program by the OS.
The contents of the word were essentially the name of the PP program and
some parameters - typically the address of a parameter block somewhere in
your segment of memory. When the OS processed the request, it cleared
location 1 (RA+1). This was the standard mechanism used to request OS
functions like writing to a file etc. Higher level languages typically
wrapped this in library functions (or macros when programming in assembler
i.e. COMPASS), but if the language allowed negative array offsets and the
ability to determine the address of the array, then it was trivial to
explicitly call PPs via RA+1 calls (even more trivial using COMPASS).

The OS periodically scanned the RA+1 words of each of several programs
currently in memory (i.e. a program assigned to a "control point") and if
the RA+1 contents were non-zero, then the OS allocated a free PP to the
request and loaded and started the requested PP program into that PP and
finally cleared the word at RA+1. You typically would expedite this by
after writing the PP request to RA+1, execute an "exchange jump"
instruction which stopped the user program from running and re-entered the
OS to allow it to soon after process pending RA+1 requests.

I hope this all makes sense.

On Thu, May 16, 2024 at 3:28 PM Mark GREEN via cctalk 
wrote:

>  I worked on the run time support for the early versions of Pascal on the
> CDC 6000 series.  Depending upon the character set determining the end of
> line was a major pain.  There was a loop hole in the Pascal type system
> that allowed you to call any PPU program directly from Pascal.  It was not
> widely known, but it came in handy at times.
>    On Thursday, May 16, 2024 at 01:52:12 a.m. EDT, Chuck Guzis via cctalk
>  wrote:
>
>  On 5/15/24 22:07, Tom Hunter via cctalk wrote:
> > I thought the CDC CYBER and 6000 series mainframes were great systems
> which
> > performed admirably for what they were designed for. I liked COMPASS,
> SYMPL
> > and NOS 1 and 2. I didn't do much work in CYBIL, but it was basically an
> > enhanced version of PASCAL suitable for operating systems work. What is
> > there not to like? These mainframes and the CDC 7600 outperformed every
> > other machine until Seymour Cray released his own machines.
>
> SYMPL was pretty new when I left the 6000 series behind.  Much of the
> code, but for some utilities was still assembly.  FORTRAN (FTN) was used
> for some simple things.
> I worked on Zodiac, which was a multi-CPU COBOL  (!) multithreaded
> multitask OS written for USAF--very unlike anything CDC has ever had..
> Lots of ECS and oceans of 844 drives. Special Systems Division was a lot
> of fun back in the day.  Lots of variety before they started cycling
> down work at SVLOPS.  My final years at CDC Sunnyvale were with STAR,
> only to be resurrected in the 1980s with the ETA machines.
>
> I think the ROVER people were among the last people at SVLOPS, but I
> can't recall precisely.
>
> A little factoid is that the 6000 series was very good at running COBOL.
>
> --Chuck
>
>
>
>
  

[cctalk] Re: Random items on Pascal #3

[Mark GREEN via cctalk]

 I worked on the run time support for the early versions of Pascal on the CDC 
6000 series.  Depending upon the character set determining the end of line was 
a major pain.  There was a loop hole in the Pascal type system that allowed you 
to call any PPU program directly from Pascal.  It was not widely known, but it 
came in handy at times.
On Thursday, May 16, 2024 at 01:52:12 a.m. EDT, Chuck Guzis via cctalk 
 wrote:  
 
 On 5/15/24 22:07, Tom Hunter via cctalk wrote:
> I thought the CDC CYBER and 6000 series mainframes were great systems which
> performed admirably for what they were designed for. I liked COMPASS, SYMPL
> and NOS 1 and 2. I didn't do much work in CYBIL, but it was basically an
> enhanced version of PASCAL suitable for operating systems work. What is
> there not to like? These mainframes and the CDC 7600 outperformed every
> other machine until Seymour Cray released his own machines.

SYMPL was pretty new when I left the 6000 series behind.  Much of the
code, but for some utilities was still assembly.  FORTRAN (FTN) was used
for some simple things.
I worked on Zodiac, which was a multi-CPU COBOL  (!) multithreaded
multitask OS written for USAF--very unlike anything CDC has ever had..
Lots of ECS and oceans of 844 drives. Special Systems Division was a lot
of fun back in the day.  Lots of variety before they started cycling
down work at SVLOPS.  My final years at CDC Sunnyvale were with STAR,
only to be resurrected in the 1980s with the ETA machines.

I think the ROVER people were among the last people at SVLOPS, but I
can't recall precisely.

A little factoid is that the 6000 series was very good at running COBOL.

--Chuck



  

Re: Desktop Metaphor

[Mark Green via cctalk]

I worked on the early Smalltalk systems, mainly variations of Smalltalk 76. 
They were there. It was the motivation for my MSc thesis which explored 
concurrent message passing for UI implementation including a demo of a system 
based on the desktop metaphor. 

Sent from my iPhone

> On Oct 23, 2018, at 8:02 AM, Peter Corlett via cctalk  
> wrote:
> 
>> On Mon, Oct 22, 2018 at 01:19:37PM -0600, ben via cctalk wrote:
>> [...]
>> That may be true but DOS/WINDOWS and APPLE II all had TV display output
>> formats, now it is WIDE SCREEN ONLY. From what little I have seen about the
>> Alto, you had a full sized 8x10? page format. The printed page DOES matter
>> for graphic displays. Try and find a printed page size PDF reader, or one a
>> tad smaller. Reading a PDF on a KINDLE DOES NOT WORK. I suspect a good PDF
>> reader, a not tablet, is needed often for all the online doc's at places like
>> bit savers to get the knowledge close to a classic computer.
> 
> The Kindle is cheap crap optimised to sell Amazon eBooks. Any feature that 
> does
> not directly push you to give more money to Amazon is made virtually unusable.
> This includes its PDF reader. I gave mine away in disgust.
> 
> I suspect that you also have a cheap crap monitor or laptop which uses a nasty
> 1080p TV panel. They have a much lower resolution than the printed page, so of
> course it's going to look like crap. A4 is 11.69" tall, and squeezing that 
> into
> 1080 pixels gives you 92DPI - worse than fax. Rotating the screen into 
> portrait
> mode gives more pixels, but now the limit is fitting the 8.27" wide document
> into 1080 pixels, or 130DPI. (Obviously, these are DPIs of the source, not the
> scaled image on your monitor.)
> 
> I have a 15" 2880 by 1800 display on my laptop, which has a pretty good PDF
> reader which will show two pages side-by-side. The resolution is high enough
> that it's as good as reading off paper, albeit scaled down to about 70% 
> because
> the screen is physically smaller than A4.
> 
> Plug my laptop into a nice HiDPI monitor -- or indeed any good-enough laptop
> into one of those cheap 4K monitors which use scummy UHD TV panels -- and PDFs
> become gloriously large and crisp. Go on, find €300 or so and treat yourself 
> to
> a new display.
> 

Re: Desktop Metaphor

[Mark Green via cctalk]

The desk top metaphor goes back to at least Doug Englebarts work in the 1960s. 
There were no icons, but the basic metaphor was there. 

You need to be careful when you talk about Smalltalk since there were several 
quite different versions of it. The early versions were far more interesting 
and experimental than the later ones. Unfortunately most of the existing 
documentation is on Smalltalk 80 which was an attempt to take the language main 
stream. I do seem to recall that the earlier implementations had icons and the 
full desktop metaphor. They may have been dropped as being to radical for the 
time. 

Sent from my iPhone

> On Oct 22, 2018, at 9:38 PM, Curious Marc via cctalk  
> wrote:
> 
> As they used to say, Windows95 = Mac 1984. Which is pushing it a bit but has 
> some truth in it... Maybe Mac 1990. Curiously, the Xerox Alto has quite 
> advanced GUI and object oriented programming (including the smalltalk 
> windowing environment), but no desktop metaphor or icons that I have seen. I 
> believe desktop metaphors appear later in the Alto commercial successor, the 
> Xerox Star, and in the Apple Lisa, which bears strong Xerox influences. 
> Xerox’s desktop metaphor pushes the object concept a bit far, while the Lisa 
> got what would become the modern ubiquitous version of the concept almost 
> dead on. Did I get this approximately right? Are there any other GUI desktop 
> metaphors that predates this?
> Marc
> 
>>> On Oct 22, 2018, at 2:19 PM, ben via cctalk  wrote:
>>> 
>>> On 10/22/2018 10:57 AM, Rick Bensene via cctalk wrote:
>>> X-Windows-based desktop metaphor UI's existed within the Unix world long 
>>> before Win95 came on the scene.
>>> The whole desktop metaphor UI existed long before Windows 95 in non-Unix 
>>> implementations by Xerox PARC (Palo Alto Research Center) with the 
>>> pioneering Xerox Alto, introduced in 1973,  which implemented  Alan Kay's 
>>> concepts for the desktop metaphor that were postulated in 1970 using 
>>> Smalltalk as the core operating system.
>> 
>> That may be true but DOS/WINDOWS and APPLE II all had TV display output 
>> formats, now it is WIDE SCREEN ONLY. From what little I have seen about the 
>> Alto, you had a full sized 8x10? page format. The printed page
>> DOES matter for graphic displays. Try and find a printed page size PDF
>> reader, or one a tad smaller. Reading a PDF on a KINDLE DOES NOT WORK.
>> I suspect a good PDF reader, a not tablet, is needed often for all the
>> online doc's at places like bit savers to get the knowledge close to a
>> classic computer.
>> 
>> I hate GUI's,because I hate ICON's. I see a little hand popup, is a mouse 
>> pointer,stop that sign, or play feel the naked photo.
>> 
>> Ben.
>> 

RE: Windows 10 recent creator release may take your printer out. I am really irri

[Mark Green via cctalk]

This has happened to me, re-installing the driver fixed the problem.

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Ed via
cctalk
Sent: July 3, 2017 1:47 PM
To: cctalk@classiccmp.org
Subject: Windows 10 recent creator release may take your printer out. I am
really irri

 
Windows 10 recent creator  release  may take your printer  out.
 
I am really irritated... my  HP 7610/7612  Officejet   printer  scanner  
etc...
 
IT WILL NOT PRINT after the upgrade.
 
I seem not to be able to bring it  back.\ Do not accept this  update if  you
are in the middle of doing something critical and need to be able to print
things  out...
 
If  you have hints or a solve for this  drop a note or post publicly  for
others that will need info.
 
None of the posted  stuff so far brought relief...
 
Thanks  Ed@  _www.smecc.org_ (http://www.smecc.org/)  

RE: In Hong Kong any old computing places to go?

[Mark Green via cctalk]

When I lived in HK (I moved back to Canada 12 years ago) you could get a visa 
to Shenzhen at the border.  It was only valid for Shenzhen, but it only took 
about 15-20 minutes.  You might check to see if they still do that.

Otherwise, head to Sham Shui Po, Apliu Street is the local electronics haven.  
There are street stalls that sell used electronics and other things, you might 
find something interesting there.  The regular electronics stores are fun to 
poke around.  On the other side of the MTR station is the Golden Arcade, which 
is the best place for computer shopping in HK.  Sham Shui Po is easy to get to 
by MTR, get an Octopus card it will save you money, you can buy them at the 
airport.  

Sham Shui Po is one of the areas that is yet to be destroyed by maniac urban 
renewal, so it's an interesting area to walk around and get some feel for older 
parts of HK.  Save an afternoon for it.

-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Christian 
Liendo via cctalk
Sent: May 27, 2017 7:27 AM
To: General Discussion: On-Topic and Off-Topic Posts ; 
Pontus Pihlgren 
Cc: jim stephens 
Subject: Re: In Hong Kong any old computing places to go?

Thanks everyone for the ideas, however I cannot leave Hong Kong and enter 
China.  That requires a different visa that I didn't obtain and I don't have 
the time to travel that far.