Re: [MLUG - DISCUSSION] hddpower usage?

[Mikhail Kovalenko <EMAIL:PROTECTED>]

Michael wrote:
> I'm thinking of putting together a little mini-itx system to act as a
> file-server. The system I have in mind has a 130W power supply and can
> hold 4 drives. I was thinking of putting in a DVD drive and three 135gig
> drives for storage. Anyone know how I'd calculate if the power supply can
> handle that kind of load? The system isn't extremely powerful but can play
> dvd/divx without problems and can rip dvd's without to much problem. Can
> hold a gig of ram and has a tv out and ethernet. Figured it'd be a cute
> littlebox to replace my vcr/dvd players.

I'd do something like this:

1. retrieve the data sheet for my drives from the manufacturer's website

2. look up drive power requirements
    for DiamondMax plus 8, for example, these are listed:
      Mode           5V  12V
      Seek (mA)    540  434
      Idle (mA)    388  358
      Standby (mA)  65   35

3. multiply the largest number of milliamps by the corresponding voltage
    and add the two numbers:
      (0.54 x 5) + (0.434 x 12) = 2.7 + 5.208 = 7.91 Watt

4. do this for every drive I have and add all the numbers together

5. I now have the maximum operating power requirement for all of my drives

Note that the actual start-up power drain may be even higher because the drive 
motors may use much higher current when they are starting up than what's 
listed on the spec sheet (that's the reason why SCSI drives have start delay 
jumpers).

Similar calculations should be done for all other components such as the CPU 
and video cards (if you can find their specifications, that is).

-- 
MK

--
To unsubscribe, go to http://mlug.missouri.edu/members/edit.php

Archives are available at http://mlug.missouri.edu/list-archives/