[comp.sys.mac.hardware] Leave it on? Or once a we

Adam.Frix@p2.f200.n226.z1.FIDONET.ORG (Adam Frix) (02/18/90)

Sho Kuwamoto (02/14/90) writes:

> I'd heard that almost all the wear and tear on a hard
> disk was due to power up and power down, where the heads might come
> into contact with the disk, or some such.  

I seem to remember, way back in the deep dark depths of my high
school electricity/electronics classes, that electric motors 
experience tremendous wear and tear on startup.  Something to do
with the current having to change the inertia of the motor.  This
was verified for me not too long ago by a furnace repairman (of all
people) who recommended leaving the furnace fan on at all times,
to eliminate the wear caused by startup.  (I was replacing furnace
fans once every year or two, and was getting tired of it.)  That
made sense to me, so I do it, and haven't had any problems yet.
Same goes for my Jasmine DD40.  (fingers crossed)  Also, putting a
fan on top of my Plus (to alleviate the demon heat) and leaving the
whole shebang on to avoid the natural surge/change of state that
powering up involves, hasn't caused any problems for me since
September 1988.

Disclaimer:  I, sir, am no EE.  Consider my story apocryphal.

--  
Adam Frix via cmhGate - Net 226 fido<=>uucp gateway Col, OH
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Adam.Frix@p2.f200.n226.z1.FIDONET.ORG (Adam Frix) (02/25/90)

Dave Smith writes:

>I'm almost convinced to leave my Mac on, but two questions are still
>unanswered:
>
>What about the Mac Plus, which has no fan.  Five or six hours and this
>thing feels hot!

I don't think it's heat per se that causes problems so much as the
constant hot-cool cycles which cause components to expand and
contract.  After enough expand-contract cycles, anything will show
signs of breakdown and disintegration.

(As an aside, I think you'll find that much of physics and life
depends not on absolute quantities, but on changes of state--classical
conditioning, for example, comes about because of a change of state
associated with something in the environment.  And so it goes.)

--Adam--

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Adam.Frix@p2.f200.n226.z1.FIDONET.ORG (Adam Frix) (02/25/90)

gft robert writes:

>One problem with leaving your computer equipment on over long periods
>of time that no one's mentioned is: lightning strikes.  Even a surge
>protector won't protect against lightning hitting power lines.  I
>always unplug my stuff during and before lightning storms.
>
>The problem is this: when you leave in the morning, it's not always
>possible to predice whether a thunderstorm will occur that day.  If it
>does, and if you've left your Mac/HD plugged in and running, you could
>be in trouble.

Absolutely.  Unplug _everything,_ phone line included.  Physically
disconnect the computer from outside influences.  I do this, too, so I
can't truthfully say that I leave my Plus on ALL the time, but for the
sake of argument...

Now, in Ohio, in the middle of February, it's a pretty safe bet that
when I walk out of the house in the morning, there won't be a
thunderstorm any time that day.  :-)

--Adam--

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