Re: Don't Fix It if it is Not Broken (was Looking at Macs...)

Mark Conrad wrote: 
In article <bPuOe.32231$XM3.26044@xxxxxxxxxxxxxxxxxxxxxx>, TheLetterK
<theletterk@xxxxxxxxxxxxxxxxx> wrote: ...lotsa good stuff trying to
pound some sense into stubborn me...


First off, lemme thank you for taking the time and effort to get me
more reasonable in my many assumptions about how the cookie crumbles
with the Mac and its software.

I obviously have a lot to learn, and it is not easy to teach an old dog
like me new tricks.  (76 years old)

Most of my time to date has been "playing" with the Mac, beating around
the bush, using utilities, without diving in and getting anything done.

For example, last night I was all worked up and worried about the Unix
command "split" , because I feared it would not handle Apple's "resource-forks". (lots Unix commands do not like resource forks)

Spent all night throwing a saddle on 'split', so that issue about the
resource forks is all solved now   :)



I know surprisingly little about everyday Mac app's.

Just recently, I bought iLife and iWork, so am looking forward to
learning how to use them, plus a slew of other app's I should buy and
install and  _use_ .



Please excuse my stubborn attitude, but it is extremely hard for me to
let go of some of my opinions and beliefs.

I  _do_  believe that Mas's OS X pretty much is capable of taking care
of itself, and therefore needs little 'diddling' or maintenance.

However, and this is a big however...

I believe 99% of file corruption problems are caused by _temporarily_ bad RAM, so called "soft" RAM failures......and also temporarily bad
circuitry in the complex CPU with all its associated support chips.
Where do you get this idea? Most of the disk problems on OS X are filesystem issues.


In other words, if RAM and all associated RAM support circuitry _and_ the CPU and its support chips were perfect and never 'temporarily'
failed, then the Mac could run essentially forever without experiencing _any_ file corruption at all.
It actively seeks out such issues for correction. There's a *lot* of 'under the hood' disk maintanence being done while the system idles.


Newer disk drives are seldom responsible for file corruption, at least
in my experience.

They can fail just like any other mechanical part.


Furthermore, disks can be hooked up in a RAID configuration such that
even if there were a 'temporary' disk glitch, the other drives in the
RAID array would catch it and keep it from corrupting a file.



So if we can agree that temporary RAM failure and temporary CPU failure
is what causes file corruption,

Could you link to some evidence regarding this?

then we can look at the factors that
can reduce the corruption caused by those temporary failures.
Nothing you've described would seem to warrant even 70% of the work you say you do. This leads me to beleive there is a serious hardware issue. Probably a disk about to die.




Now it stands to reason that if I have two dual G5 Macs, and one of
those Macs has only 500 MBs of RAM, and is used by a little old lady
who runs a word processing app' , then that Mac's CPU and RAM will be
idling along with little strain on the CPU and RAM.
Not at all--OS X performs a number of maintanence tasks when idle. It's also much more liberal in it's usage of RAM and VM than most systems.

   Bottom line on this lightly loaded Mac, little RAM to fail, and the
CPU is idling with a lot of its internal circuits not being used, so
few soft errors will happen with this Mac.
The frequency of errors shouldn't change dramatically with the amount of load the system is under.




Our other G5 has 8 GBs of RAM, 16 times more RAM, therefore that RAM is
16 times more likely to develop soft failures when it is heavily used.
The chances of failure do not accumulate. If there's a .05% chance of data corruption (absurdly high) with 1GiB of RAM, there will also be a ..05% chance of data corruption with 8GiB. Assuming the physical modules are (relatively) identical, of course.


There are other bad factors at work also, the greater amount of RAM
will take 16 times longer to refresh, so the voltage in individual RAM
cells drops to lower values, much more liable to fail.

The CPU is heavily loaded trying to do several tasks at once, hot as a
pistol, and that blowtorch heat can cause more soft failures, as can
the fact that many more of the CPU's transistors etc. are being used,
and the more of those transistors in use, the more likely soft failures
are to occur.
If your running a system under load, at factory conditions, there shouldn't be any sort of problem here. If your encountering such problems, you've most definitely encountered a serious hardware failure. There is absolutely no reason you should be doing the kind of disk maintanence you are. It doesn't matter what load your powerbook is under--the schedule your claiming is absurd, and unnessesary if the system was working as designed.




Therefore I can not agree that a whole bunch of 3rd party app's trying
to run at once do not heavily contribute to file corruption caused by
'soft' failures.

Can you backup your claims with some hard evidence?


This file corruption can occur in system files,  and/or  application
files.   If the added corruption on the heavily loaded Mac occurs in a
system file,  _sometimes_  that corruption can be repaired by "extra"
maintenance.  (sometimes it can't, of course)

Bottom line, extra maintenance can often benefit a heavily loaded Mac,
or a Mac in a hot environment, or a Mac with old RAM and old
components.
No, no it can't. OS X will almost always do a better job of disk maintanence than it's administrator will. The only time an administrator should be involved is when *** hits the fan.
.

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