As he leans on his cane, the old codger says....
Well Disks used to come in open cannisters, that is you took the bottom
cover off, and then put the whould pack into the drive, and then
unscrewed the top cover and took it out.. Clearly ventilated. C 1975.
Later we got sealed drives, Kennedy 180 MB Winchesters they were
called (the used IBM 3030 technology). The had a vent pipe with two
filters, you replaced the outer one every 90days (as part of the PM
process). The inner one you didn't touch. Aparently they figured that
it'd be a long time before the inner one got really clogged at 10 min
exposure every 90 days. C 1980
Still later we had a Mainframe running Un*x, it used IBM 3080 drives
these had huge HDA boxes that wree sealed but hav vent filters that had
to be changed every PM (30 days, 2 hours of down time to do them
all). C 1985.
So drives do need to be ventilated, not so much wory about exploding,
but rather subtle distortion of the case as the atmospheric preasure
changed.
Doe anyone rememnber that you had to let you drives acclimate to your
machine room for a day or so before you used them.
Ah the good old days...
HUH???
<scw>
On Thu, Feb 22, 2007 at 10:27:43PM +0000, Nix wrote:
> On 20 Feb 2007, Al Boldi outgrape:
> > Eyal Lebedinsky wrote:
> >> Disks are sealed, and a dessicant is present in each to keep humidity
> >> down. If you ever open a disk drive (e.g. for the magnets, or the mirror
> >> quality platters, or for fun) then you can see the dessicant sachet.
> >
> > Actually, they aren't sealed 100%.
>
> I'd certainly hope not, unless you like the sound of imploding drives
> when you carry one up a mountain.
>
> > On wd's at least, there is a hole with a warning printed on its side:
> >
> > DO NOT COVER HOLE BELOW
> > V V V V
> >
> > o
>
> I suspect that's for air-pressure equalization.
>
> > In contrast, older models from the last century, don't have that hole.
>
> It was my understanding that disks have had some way of equalizing
> pressure with their surroundings for many years; but I haven't verified
> this so you may well be right that this is a recent thing. (Anyone know
> for sure?)
>
> --
> `In the future, company names will be a 32-character hex string.'
> --- Bruce Schneier on the shortage of company names
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