Re: To shut down or not?

[mjmahon@aol.com (Michael J. Mahon)]

twohandsfree@hotmail.com  (John) wrote:

<snip>

>Random thoughts from a hobbiest regarding on or off ...
>
>
>                      -- Reasons to turn it off --
>
>- Mechanical wear on HD and fans. The HD on my Focus cards are second
>hand and I've read posts about, and experienced, HD failure. I believe
>bearing wear on older HDs is a factor (but if it is badly worn ....
>see below).
>
>- Power or surge protection is a good idea (a running Apple *may* be
>more vulnerable)
>
>- You are wasting a small abount of power (green or mean)
>
>- Monitors have a finite life (turn them off screensaver or not). 
>
>- Apple batteries don't cost much. Meanwhile you can slap a AA over
>the dead battery. Radio Shack has holders - ugly but cheap & available
>locally.

The required voltage is 3.6v, so it will take two alkalines, at least.

And you should _never_ parallel a non-rechargeable lithium battery
with a good battery--the results could be explosive.  ;-)

>- Warm plastic leaches plasticizers faster (uneven discolorization?,
>cracking)

Discoloration of Apple cases seems to be more a function of the
amount of ultraviolet light they receive than the temperature.  I've
seen cases that clearly "imaged" a shadow cast on them.

>? capacitors dry out faster when warm (seems logical)
>
>
>
>                    -- Reasons to leave it on --
>
>+ every heat cycle extends tiny cracks in silicon chips. 
>
>? Potentially damaging (?) power surges each time you flip the switch 
>
>? Near death HDs seem to have trouble on start up. For example, one
>Focus drive failed to boot, not when it was on. A second Focus card
>has to be coaxed to boot too.

This may be the case even with drives that are not "near death".

The phenomenon can be caused by stiction between the head(s) and
the ultra-smooth surface of the platter(s), and the bearings are not
always the culprit.  A "knock" or a "wiggle" about the rotational axis
during startup will often free them up.

You are certainly correct that stiction is only an issue if a drive is
turned off, which is when the head(s) settle into intimate contact
with the platter(s).

Modern drives have a very fine texture applied to the platters
to prevent stiction if they are designed to "park" the head(s) on
the platters.

-michael

Check out amazing quality sound for 8-bit Apples on my
Home page:  http://members.aol.com/MJMahon/