Electrical damage (was - Re: [LINK] Leave on, or turn off?)

[Richard Chirgwin]

Stewart Fist wrote:
> Also for home computers, especially when users are at work, the risk of
> leaving the machines linked to powerlines during thunderstorms must be a
> major consideration.  In pure monetary terms, this probably outweighs any
> concern about hard-disk bearing wear.
>   
A detail ... have another look at your ADSL setup. The ADSL modem uses 
the unfiltered phone line. Lightning filters for ADSL are rare to the 
point of nonexistennce - so a good thunderstorm will kill the modem (as 
has happened to me with a D-Link a couple of years back, which is why I 
tried to buy a DSL-friendly lightning filter).
> A couple of other sub-questions:
>
> 1. If a PC goes into sleep mode, turns down its hard-disk, and cuts power to
> its monitor, wouldn't it suffer pretty-much the same thermal shock when it
> powers up ?
>
> Doesn't that kill the thermal-shock argument?  Although, as Ivan points out,
> most modern machinery is designed to accommodate this.
>   
I didn't take much notice of the 'thermal shock' argument before, but it 
doesn't accord with experience. In an electronics shop, people will 
happily freeze a circuit board (what do we use for freezer spray now 
that CFCs are ancient history?) in spots to identify a failing solder 
joint. In most mouths, the words 'thermal shock' probably rank as urban 
myth - people repeating something someone told someone else once ...

RC
> 2. How do servers stand up against desktop PCs in terms of long-term
> reliability?  Are differences just due to more attention to cooling or
> better components, or is there some other factor involved ?
>
> 3 Do hard-disks wear out faster when they are constantly accessed ?  Or is
> the life-span set purely by running time, irrespective of actual usage.
>
>
>