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From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: Serial, concurrent, parallel
Date: Thu, 16 Jan 2025 16:27:31 +0000
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On 16/01/2025 11:41, Don Y wrote:
> On 1/16/2025 3:14 AM, Martin Brown wrote:
>> On 14/01/2025 18:10, Don Y wrote:
>>> I am surprised (disturbed?) at the problems people seem to have
>>> sorting these things out in their thought processes.  I don't
>>> *believe* people think strictly "serially" but I am beginning to
>>> question that belief as I witness smart/capable people stuck in
>>> that mindset!
>>
>> Most people do think in a very linear fashion so I'm not too surprised 
>> at your finding. Good realtime programmers are as rare as hen's teeth.
> 
> When you think of a circuit diagram, do you "track" an electron through
> the wiring?  Don't you conceptualize "this block does this WHILE this
> other block is doing that"?
> 
> People seem to tolerate the notion of an ISR running WHILE their code
> is running.  They don't seem to think of it as "my code is running and
> THEN an interrupt comes along and does...".

An ISR is sufficiently small and so mission critical that if it doesn't 
save and restore the registers it affects properly the OS dies PDQ.

> Yet, when they think of multitasking (and beyond), they seem to
> intentionally serialize the actors' actions.  Why the difference
> in mindsets?

Most people can't imagine the various tasks running at different speeds 
either timesliced or by priority. There is always a tendency amongst 
programmer to think that their task is *the* most important one. The 
thing you learn quickly on truly massively parallel hardware is that the 
manager task that keeps all of the allocated workers busy is by far the 
highest priority.

>> It could be "solved" by the addition of suitable small delays here and 
>> there to prevent the race condition triggering. Heavy users went back 
>> to XL2003 which I recall was a particularly good vintage.
> 
> Dunno.  I've not used a spreadsheet since Quattro.  Never really saw the
> appeal (if I need some set of values calculated, I'll just write a bit of
> code to do it unambiguously -- instead of wondering what quirks the

I like spreadsheets for making test data. The sort of mistakes you can 
make in a spreadsheet implementation are almost entirely orthogonal to 
those you can make in a conventional programming language. As such it 
makes a great scratch pad for developing tricky algorithms with all of 
the internal workings clearly visible on the screen.

> spreadsheet imposes).  Especially as so many people seem to use 
> spreadsheets
> in lieu of (real) databases.  :<

Sigh - yes I know they do :(
Up to a couple of thousand lines it isn't *too* bad but after that it 
goes downhill very quickly. Doesn't stop people - typically middle 
managers with very limited skills having silly sized ones though.


-- 
Martin Brown