[LINK] Leave on, or turn off?

[Ivan Trundle]

On 30/11/2006, at 12:36 PM, Howard Lowndes wrote:
>
> Stewart Fist wrote:
>> Has anyone got a reference to a real bit of reliable research  
>> which says
>> whether it is better to turn a computer off at night, or leave it  
>> on 24/7
>> (disregarding energy consumption) ?
>> I guess the question resolves into
>> a) the electronics, and
>> b) hard-disk-bearing wear.
>> I've got plenty of so-called 'expert' opinion (mostly in favour of  
>> leaving
>> computers on), but this seems essentially to be anecdotal only.
>
> Anecdotally, my experience is that those machines which give more  
> trouble are those which are subjected to thermal shock mostly be  
> being regularly tuned off and on, which usually causes memory  
> modules or PCI card connection to become random.
>
> Economically you need to offset the cost of the occasional service  
> to rectify such faults against the cost or 24/7 operation.
>
> My money says, leave it on, but turn the CRT off - I've seen them  
> catch fire.

There are too many variables to take stock of here:

1. What is 'better', and what is 'better' measuring? What is the real  
question here? How can anyone disregard energy consumption, or heat/ 
noise output when performing these calculations?

2. What is a 'computer'? If it's a laptop, then one also has to  
consider that it has the potential to burn and explode (the Sony  
battery story) whilst unattended.

3. Most modern computers are set to go into 'sleep mode' after a  
period of inactivity, and hard disks spin down, monitors sleep, etc.  
How does one measure this in the overall matrix of information?

4. From a purely engineering perspective, thermal shock is a  
consideration - but surely most modern machinery is designed to  
accommodate this  as part of the projected life of the item?

5. And what *is* the intended life of the device? Manufacturers have  
different MTBF ratings for their equipment.

6. And what is the machine actually used for (server/occasional use/ 
desktop/laptop/etc)?

With all this in mind, I'm certain that any picture can be painted to  
justify leaving a machine on/turning it off/letting it sleep/whatever.

iT