# Re: Square root of a negative rral value

*From*: "robin" <robin_v@xxxxxxxxxxx>*Date*: Sat, 29 Nov 2008 21:39:49 GMT

"Glen Herrmannsfeldt" <gah@xxxxxxxxxxxxxxxx> wrote in message news:ggpfmr$nj9$1@xxxxxxxxxxx

Gary Scott wrote:

(snip)

Its fairly well known in the electronics industry that component failure

is intentionally designed in (designed just good enough but not too

good). I hope they werent in that mode of thinking that early :(

For incandescent light bulbs there is a known trade off between

life and visible light output. Knowing the cost of electricity,

the cost of bulbs, and the cost to change bulbs one can find the

optimal point on the curve. For industrial use, where you pay someone

to replace bulbs that may be in hard to reach places, the optimal

point is a little different than for home use.

For other components the trade off might be less obvious.

That is entirely irrelevant.

Valves used in computers were ordinary domestic ones as well as

special quality ones. The latter had a guaranteed life of 10,000 hours

(to maintain their characteristics), and characteristics were

more consistent between valves. Of course, valves lasted much much

longer than that (10,000 hours), just as they did in domestic radios.

It should also be noted that computers were not turned on and off

repeatedly, but kept running continuously (maybe all week).

Of course, if the computing was completed the computer would be switched off

at the end of the night. They would also be switched off to carry out

component replacement such as resistors or capacitors, or to check

component values, etc.

.

**Follow-Ups**:**Re: Square root of a negative rral value***From:*Glen Herrmannsfeldt

**References**:**Square root of a negative rral value***From:*Terence

**Re: Square root of a negative rral value***From:*Gordon Sande

**Re: Square root of a negative rral value***From:*Glen Herrmannsfeldt

**Re: Square root of a negative rral value***From:*Terence

**Re: Square root of a negative rral value***From:*e p chandler

**Re: Square root of a negative rral value***From:*Terence

**Re: Square root of a negative rral value***From:*robin

**Re: Square root of a negative rral value***From:*Terence

**Re: Square root of a negative rral value***From:*robin

**Re: Square root of a negative rral value***From:*Gary Scott

**Re: Square root of a negative rral value***From:*Glen Herrmannsfeldt

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