mr@isrnix.UUCP (michael regoli) (01/10/86)
]:[ ]:[
how many folks out there "park" your read/write heads
*daily* when you power down your pc's?
i have a 20 mB external and do it out of habit (especially
if someone wants to cut the cables and steal the drive. i
figured it's the least i can do!-))
i recall seeing somewhere that stray energy (signals, vibes,
call it whatever you like) can be transferred through the
heads onto the disk when powering-down thereby causing loss
and/or corruption of data.
how important is it to park the heads (take them away from
the media and place them in a safe spot)? [of course, you
would always want to park the heads when you move the drive
and/or prepare the drive for shipment.]
i'd appreciate hearing more about this practice.
--
--
.^. michael regoli
/|\ ...ihnp4!inuxc!iuvax!isrnix!mr
'|!|` <mr@isrnix.UUCP> entropy@fluke.UUCP (Terrence J. Mason) (01/16/86)
I have a Shugart SA-712 and always park the heads before powering the thing down. I checked with someone familiar with Shugarts burn-in and test procedures who said that mechanically there is no reason not to land the heads anywhere that you want (other than the travel issues). However, I don't really trust my controller board (OMTI 20-L) not to squirt out little dribbles of current in the process of powering down, so I don't take the chance. Paranoia has even prompted me to consider modifying my system software to force the heads to idle over the 'landing zone' when the disk has not been used for a few minutes, so that if I suffer a power failure the heads are more likely to land in the correct place. terrymason (entropy@fluke)
keithe@tekgvs.UUCP (Keith Ericson) (01/18/86)
In article <659@isrnix.UUCP> mr@isrnix.UUCP (michael regoli) writes: >]:[ ]:[ > > >how many folks out there "park" your read/write heads >*daily* when you power down your pc's? > I *never* power down my PC. And it's 'cause I have problems sometimes getting the 10 meg hard disk to come up to speed when I power it up again. I can get it going, but I have to putz around with it. So I just *never* shut the thing off. I've been operating like this since last Thanksgiving. keith
mr@isrnix.UUCP (michael regoli) (01/20/86)
]:[
well, i wanted to follow-up to this article and let you know
what i have found.
it seems that _everyone_ who wrote me parks their heads regularly;
on a daily basis. one gentleman wrote and said he parks the heads
even to leave his desk for a short time. you never can be too
cautious (esp. if you work in the middle of a large, busy room.)
parking does no damage and may help in the long run -- even if your
location is prone to brown/black-outs.
one individual indicated that dos provides no utility to park the
heads.
maybe someone out there can post some code to assist in this endeavor.
--
--
.^. michael regoli
/|\ ...ihnp4!inuxc!iuvax!isrnix!mr
'|!|` <mr@isrnix.UUCP> raymund@sci.UUCP (Raymund Galvin) (01/21/86)
In article <1322@tekgvs.UUCP>, keithe@tekgvs.UUCP (Keith Ericson) writes: > In article <659@isrnix.UUCP> mr@isrnix.UUCP (michael regoli) writes: > >]:[ ]:[ > > > > > >how many folks out there "park" your read/write heads > >*daily* when you power down your pc's? > > > I *never* power down my PC. And it's 'cause I have problems sometimes > getting the 10 meg hard disk to come up to speed when I power it up > again. I can get it going, but I have to putz around with it. So I > just *never* shut the thing off. I've been operating like this since > last Thanksgiving. > > keith I don't think leaving the PC on indefinitely is a good idea. The MTBF of typical small hard disks is usually between 5000 and 10000 hours. This implies that a hard disk that has been powered up since 11/28/85 is 25% along the way to a failure. These failures are the real nasty ones - where the drive needs to be replaced or repaired - not just a read error. Ray Galvin
keithe@tekgvs.UUCP (Keith Ericson) (01/24/86)
[a continuing saga, edited for brevity] >> >how many folks out there "park" your read/write heads >> >*daily* when you power down your pc's? [michael] >> > >> I *never* power down my PC. [keith] >> >I don't think leaving the PC on indefinitely is a good idea... >A hard disk that has been powered up since 11/28/85 is 25% along the >way to a failure. [ray] I'll let you all know when it dies. As long as it lasts long enuff to get it onto my weekly (monthly?) (occasional?) tape backups...:-) keith
desj@brahms.BERKELEY.EDU (David desJardins) (01/24/86)
In article <144@sci.UUCP> raymund@sci.UUCP (Raymund Galvin) writes: > >I don't think leaving the PC on indefinitely is a good idea. The MTBF >of typical small hard disks is usually between 5000 and 10000 hours. > >This implies that a hard disk that has been powered up since 11/28/85 >is 25% along the way to a failure. These failures are the real nasty ones - >where the drive needs to be replaced or repaired - not just a read error. This number is just that, a "*mean* time between failures." In particular it is based on an average pattern of usage. Obviously a hard disk which is just idling will be less likely to break down than one which is being used. Most hard disk failures presumably involve the head, which should be affected relatively little by running the drive continuously. On the other hand there certainly are bearings and such in the drive mechanism which can fail even if the disk is not being accessed. Can anyone give us a reliable estimate of the MTBF for a drive which is on for long periods but is accessed relatively rarely? This should also be of interest to BBS operators, etc. -- David desJardins
neese@curly (01/27/86)
Most of the full-height hard drives will automatically park
the heads on a landing zone. This is true of Quantum, Micropolis
and Seagate. These drives shutdown the read/write circuits as soon
as power is lost and in the case of the Quantum, if power drops
below a certain level it will shut off the read/write circuit and
perform a recalibration of the head assembly. So I don't see any
benefit to parking the heads of these drives.
On half-height hard drives, it is a good idea. I do not know of
any half-heights that automatically park the heads for you.
Roy Neese
UUCP @ .. {ihnp4!convex!ctvax,microsoft}!trsvax!sysvis!cpe!curly!neese
.. {ihnp4!convex!ctvax,microsoft}!trsvax!doc!cpe!curly!neese
.. {ihnp4!convex!ctvax,microsoft}!trsvax!vaxnix!cpe!curly!neese
.. {ihnp4!convex!ctvax,microsoft}!trsvax!sneaky!cpe!curly!neese
nqcdsf:curly!neese