Fortran (Was Re: PDP-8 Straight 8 restoration) (Resubmitting without attachment)

Nigel Johnson nw.johnson at
Mon Mar 30 12:26:11 CDT 2020

Since we are all at home exchanging stories, I thought I would regale 
you with my best punch card one:

My first job out of school was at Bell Canada in  Downtown Toronto.

I was trained as an FE on their Univac 418 II systems that ran a 
Canada-wide store-and-forward MSDS - Message Switching Data Service 
(MSDS - means something else now!)  I also got trained on the PDP11, 
then PDP8, and Interdata 50.

The year was 1972 or '73 I think.

Since there was very little operating to do with a real-time system, we 
didn't have operators and did all the operating ourselves.  One system 
ran H23 (it had to be shutdown for maintenance over midnight because the 
system would crash if the time went backwards after midnight), the 
other, use by stockbrokers and the T. Eaton Company started at 0600 and 
was turned down at 2100.

Being critical real time (after all, it fed about a thousand 110 baud 
teletypes across Canada :-) ) it would crash sometimes due to racing 
conditions that had not been forecast.  Instead of re-assembling the 
system (about four hours), the programmers would issue us with PARLO 
(PARameter LOader) cards to make patches after we loaded the enterprise 
code and before we started it.  This fixed the bugs by binary changes.

One morning, I was on duty as the 0600 system crashed immediately after 
I started it.  As trained, I switched all the peripherals over to the 
backup machine and loaded the program on there, carrying the PARLO cards 
over and running them before I started that system. Same crash happened, 
while the panic dump was still running between the first computer and 
the Uniservo VI C.

Lots more attempts happened, including running heavy cables across the 
floor to patch in spares that were not on the transfer switch, until 
first, second, and finally third level managers were standing behind me 
as I tried new things.  "A 20-year old does not need this kind of 
stress", I thought!

Upper management wanted to 'get somebody else' to work the computer by 
my boss told me to stand fast.  Suddenly, I had an idea.  We had an old 
IBM 028 punch sitting at the back of the room.

"Go and copy these PARLO cards" I said to the programmer.  She scowled 
at being told what to do by this young kid, especially since she was 
management and I was not. But as nobody had any better ideas the 
managers told her to do it.

Thankfully, my idea that the PARLO cards were worn thin so that the 
photo readers could see holes where there were not, was accurate. The 
028 used fingers to feel for the holes and so made a perfect copy!

After that they instituted a policy of changing the PARLO cards or 
re-assembling on a regular basis!

The attachment is a picture of where this happened.


Nigel Johnson

On 30/03/2020 11:41, Diane Bruce wrote:
> On Mon, Mar 30, 2020 at 09:31:56AM -0600, Warner Losh wrote:
>> On Mon, Mar 30, 2020 at 8:13 AM Diane Bruce <db at> wrote:
>>> On Sun, Mar 29, 2020 at 05:33:35PM -0600, Warner Losh wrote:
>>>> On Sun, Mar 29, 2020, 5:10 PM Diane Bruce via cctalk <
>>> cctalk at>
>>>> wrote:
>>> ...
> ...
>>> A dropped card deck was disaster and how many folks filled in columns 73
>>> to 80
>>> with an index? Not very many. :-(
>> Worse: 80% of the cards had that, but the other 20% didn't since they 
>> were
>> later bug fixes.
>> The decks that I had to verify were from the "in the barn" days of the
>> company and had sat in storage for a few years. People would remove cards
>> from the top box in the stack to show visitors and weren't great about
>> putting them back exactly in order... So when the boss, who was sure he
> And the cards bent due to humidity and stuck together while you read 
> them right?
>> semi-real editor (visual TECO at a glorious 4800 baud). and I learned 
>> a lot
>> about FORTRAN and just how bad it could be (the boss was a great
>> businessman, much better than his FORTRAN prowess).
> The worst Fortran I remember was from Scientists. I got to fix some of 
> that
> back in the day. Nowadays a lot of them learn C/C++ and are not horrible
> coders now. Early Fortran as you remember was pretty easy to turn into 
> spaghetti
> code. WATFOR and IFTRAN helped.
>>> Ah yes the LARGE array with indexes used as pointers trick. *ugh* I
>>> remember.
>> Yea. And ugly tricks to overlay/alias heap1, heap2 and heap4 (which were
>> for byte, word and longword access respectively). And converting between
>> the different "pointer" types. It was helle ugly... But pointers in C 
>> that
> Yep. yep.
>> I learned a few years later were a piece of cake in comparison...
> Pointers were a treat compared to the horrible Fortran mess and was very
> appreciated.
>> Ha! We had some assembler for the most time critical bits, but we wrote
>> that in MACRO-11 directly and linked it in.
> Yep. BTDT I did a lot of 'raw' MACRO-11 too.
>> Warner
> Diane

Nigel Johnson

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