[plug] Fax & Voicemail Random Thought...

[Bret Busby]

On Thu, 25 Jul 2002, Craig Ringer wrote:

> 
> > Survival of the computer, and especially of everything on the hard disk. I
> > thought that would be obvious, from what I stated.
> Well the disk can be taken care of by our friend the journalling file 
> system. No disk for the last 10+ years has needed to be "parked" or 
> otherwise protected from sudden power failures, the hardware will be fine.
> 

1. Isn't journalling part of ext3, rather than ext2? If so, doesn't that
cause problems trying to access journalling systems, from systems that are
ext2, such as RH 6.2? (Still in the process of switching to RH7.3, but
will still keep RH 6.2)

2. After power problems (eg, pushing the off switch instead of the CD
eject switch, which are only about an inch apart), files, other than tmp
files, are sometimes converted or whatever, to the status or whatever, of
6 (I remember the number, but not what is done, that achieves the
number), during the subsequent fsck. The files have included /dev and /var
files. I do not know what damage has been done, but, it appears that files
do get damaged (apart from the ones that at the same time, get the wrong
lengths and things, that also need "fixing").

> The computer won't be damaged by power loss.

Given the damage that has been done to appliances that we have owned, and
the short lifetimes of light globes in this house, due to the unstable
electricity supply ("not another fridge thermostat gone!" - $200 each
time), and, given that we have a computer that now makes funny wheezing
noises, sometimes, when we turn it on, I disagree. It is also probably why
the stepper motor on my 10MB HDD has to be kickstarted, most of the time,
on one of my computers.

> 
> There is more concern about big surges etc - a decent PC PSU can take a 
> _big_ spike with no more problems than a crash-halt of the system. This 
> isn't something one relies on if possible, though. If a spike comes up 
> your phone line ... bye bye magic smoke :-( still a decent surge 
> protector can provide good (but not perfect) protection against power 
> and phone line surges.
> 
> So really, there's no problem with leaving a PC on 24/7, and many have a 
> BIOS option to auto-reboot on power loss too, so your machine comes 
> straight back up after a power failure.
> 

Looking after our PC's, and protecting them (as much as possible from a
wonky power supply), and turning them off when not needed, to avoid power 
problems, is why we still have hard drives that operate without any
problems, that are over 10 years old.

> Of course for anything truly critical (hideously expensive, mission 
> critical for work, or whatever) a proper UPS with battery pass-through 
> and good power conditioning is a must.
> 
> 

To students, everything on the hard drive (that is related to study, not
blue pictures :), is critical, or, should be. More than one PhD student
has lost their thesis, just before handing it in, due to computer
failures. Similarly with all other kinds of data, such as financial data,
etc.

In Armadale, a computer with anything of value on the hard drive,
warrants a good UPS. It's like travelling in a car wearing a seat belt -
it's a matter of survival (and, works, for most cases).

-- 
Bret Busby
Armadale
West Australia
..............

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