The General Approach to Computing - A Ramble

Tony Duell ard at p850ug1.demon.co.uk
Fri Apr 24 14:21:32 CDT 2009


> First, I'm not a Luddite, or troglodyte, or anything similar.  I love 
> using the finest, newest devices of all kinds, including computers.  

Well, I'll use the new stuff when it offers an advantage over the older 
stuff (and I consider both the performance of the old and new, the ease 
of repair, the 'useability' and so on). Certainly if the older version 
does what I want, I kep on using it.

> And, while I like playing with the old computers, and fixing them, 
> nothing beats screaming speed in a personal computer.

Now that's something that's never bothered me .If my machine takes 10 
minutes to complie my program, so what? I just do something else while 
it's compiling. And it gets me to check my code before compiling it, 
hopefully ending up with a etter program (the 'poke and hope' brigade 
worry me -- changing things until the program compiles and/or runs)

> My background is as a National Institute of Standards and Technology 
> Calibration Technician.  Call me fixed in my ways if you like, but I 
> prefer finding a (small) failed component, getting a replacement for 
> under a dollar, and spending an hour or two troubleshooting and fixing 

I am suprised I didn't write that...

[...]


>     There are millions of people driving cars that have no idea how to
>     do anything other then put gas in it and maybe change the oil. Why
>     should computer (another tool like a car) be any different today?
> 
> 
> Think about what you're saying...  There ARE people who like to futz 
> around with their cars, like I like to futz with my computer.  All the 
> people like that I know are not happy about computer control of the 
> engine, as it makes it difficult to the point of near impossibility for 

Nor am I. I don;t drive, but I get to fix my father's car, and he's 
recently changed it. It's a small, pretty much base-model car. The 
workshop manual is _11_ volumes, and takes up over a metre of shelf space 
(compare that to the manuals for older, higher-specced cars that are one 
book, about half the thickness of _one_ of these volumes).

But actually, cars have got easier to repair (provided you don't bleieve 
the propaganda put out by the manufactuers and the garage trade). I've 
read plenty of manuals for older cars where the only tool you use for 
finding electircal fauts is a test lamp, or maybe a multimeter. And you 
had to press in neaw bearing bushes and the hand rema them to size. At 
least one manual I've read requires the use of a lathe for some repairs.

Nowadays, electrical fault-finding consists of plugigng a 'diagnostic 
tester' into the CAN busREad out the error codes from the approriate ECU 
(Electronic Control Unit). Perhaps the error will be something like '<foo> 
sensor output meaningless' So you look it up in the manual. It'll tell 
you to meausre the resistnace between a couple of pins on the ECU 
connector. If it's within range, change the ECU (beacuase that ADC input 
channel has failed, no it doesn't say _that_ in the manual). If it's out 
of range, meaure the resistanve between the pins on the sensor. If that's 
within range, check/repair the wiring. If not, change the sensor. 

And there's a no hand-fitting of mechancial parts, reaming, turning, etc. 
Partly because things are now made to closer tolerances, but more because 
you replace entire units, not just the defective part. Darn it, there's 
no seal kit for the brake master cylinder, you have to change the 
complete cylinder. No spares for the pawer steering pump or rack (and yet 
I haev the manaul for a much olfer car that give detailed descriptions 
and exploded diagrams for the power steering units). And so on.

And no, I am not happy about this _at all_.

-tony




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