cotner@jif.berkeley.edu (Carl Cotner) (07/18/88)
After some recent discussions and testimonials on the net, I've been convinced that I should leave my PC and hard disk on 24 hours a day to spare it the trauma of being powerred it on and off each time I use the machine. Now I hear that I should park the heads of my disk whenever it is not in use to prevent data corruption from a power surge. That sounds reasonable. When I bought my Mountain HardDrive, the disk came with a head parking utility for such a purpose. Now I'm wondering how do I UNPARK the hard disk to use it again? As far as I know, I have to turn off the PC and turn it back on in order to bring up the hard disk. However this this seems to defeat the purpose of leaving the computer on continuously to save wear and tear on the hard disk. Can anyone set me straight? Is there a utility to unpark a parked disk? Thanks for any advice and input. cc PS: I'm also leaving my monitor on 24 hours a day, but with the brightness switch dimmed to pitch black, operating under the same assumption that transients during power on is not good for the monitor either. Is this a reasonable assumption, or should I just switch the monitor off?
bkliewer@iuvax.cs.indiana.edu (Bradley Dyck Kliewer) (07/18/88)
In article <12184@agate.BERKELEY.EDU> cotner@bosco.berkeley.edu.UUCP (Carl Cotne > >As far as I know, I have to turn off the PC and turn it back on >in order to bring up the hard disk. However this this seems to defeat the >purpose of leaving the computer on continuously to save wear and tear on >the hard disk. Can anyone set me straight? Is there a utility to unpark a > >PS: I'm also leaving my monitor on 24 hours a day, but with the brightness >switch dimmed to pitch black, operating under the same assumption that >transients during power on is not good for the monitor either. Is this >a reasonable assumption, or should I just switch the monitor off? Simply accessing the disk will unpark it (unless your park program hangs the computer). I have seen a park utility which locks out the keyboard so the power must be turned off (although Alt-Ctrl-Del might work). All a park program usually does is move the head to the very last cylinder (which is not supposed to used). Any disk access (such as DIR, reading or writing) will move the head off the park track. As far as monitors are concerned, turning them on and off seems to put quite a bit of strain on the circuitry (my EGA monitor just fried itself this weekend). However, because of the strong, rapidly oscillating electric and magnetic fields, there is also a lot of stress during operation. My preference is to turn monitors off for the night, but never during the day. Note: I knew my monitor was going bad -- it had problems starting up, so I kept it running continously. I suspect this extended the life very slightly, but it burned up anyway (leaving quite a bad smell in the house). Bradley Dyck Kliewer Hacking... bkliewer@iuvax.cs.indiana.edu It's not just an adventure It's my job!
tomk@lakesys.UUCP (Tom Kopp) (07/19/88)
In article <12184@agate.BERKELEY.EDU>, cotner@jif.berkeley.edu (Carl Cotner) writes: > Now I hear that I should park the heads of my disk whenever it is not in > use to prevent data corruption from a power surge. That sounds reasonable. > When I bought my Mountain HardDrive, the disk came with a head parking utility > for such a purpose. Now I'm wondering how do I UNPARK the hard disk to use it > again? > > As far as I know, I have to turn off the PC and turn it back on > in order to bring up the hard disk. However this this seems to defeat the > purpose of leaving the computer on continuously to save wear and tear on > the hard disk. Can anyone set me straight? Is there a utility to unpark a > parked disk? Carl...Now maybe the Mtn HD is different, though I doubt it. All hard drives I've worked with (Siders, internals on PS/2's etc) Were parked by means of a program (which you apparently have). All this does is move the head away from the recording platter. The reason your manual probably tells you to turn it off is, I think, drives are usually parked for shipping. My guess is that the next read/write command you issue will 'unpark' the head. (Lemme know if I'm wrong on this, folks) B-) -- _____ _____ |"Reading computer manuals without |tomk@lakesys.UUCP | | | the hardware is as frustrating as |uunet!marque!lakesys!tomk | \_| | reading sex manuals without the |uunet!uwmcsd1!lakesys!tomk ------------- software" - Arthur C. Clarke ----------------------------
EACELARI@pucc.Princeton.EDU (Edward A Celarier) (07/19/88)
In article <12184@agate.BERKELEY.EDU>, cotner@jif.berkeley.edu (Carl Cotner) writes: >After some recent discussions and testimonials on the net, I've been >convinced that I should leave my PC and hard disk on 24 hours a day >to spare it the trauma of being powerred it on and off each time I >use the machine. > >When I bought my Mountain HardDrive, the disk came with a head parking utility >for such a purpose. Now I'm wondering how do I UNPARK the hard disk to use it >again? > No, no. The next time you issue any instruction to the disk, it will unpark itself. In fact, the PARK utility I have brings the CPU to a grinding halt after it parks the disk, precisely to avoid this happening! I would not place bets on leaving the disk running all the time, though I know plenty of people who do just that. I am just a little uncomfortable with the idea that some environmental problem may crop up while I'm away (like jack-hammering on the floor below -- don't laugh, this happened to me). Also momentary power failures (e.g. during electrical storms) can make it go bonkers (you will have to reboot anyway, since your controller will have gotten confused). I wonder if there are some authoritative engrg. types out there who can address this issue as something other than a question of "religion". >PS: I'm also leaving my monitor on 24 hours a day, but with the brightness >switch dimmed to pitch black, operating under the same assumption that >transients during power on is not good for the monitor either. Is this >a reasonable assumption, or should I just switch the monitor off? Probably, you should just switch it off. Transients won't be any good for the things you can't see, too!
anand@vax1.acs.udel.EDU (Anand Iyengar) (07/19/88)
In article <12184@agate.BERKELEY.EDU> cotner@bosco.berkeley.edu.UUCP (Carl Cotner) writes: >Now I hear that I should park the heads of my disk whenever it is not in >use to prevent data corruption from a power surge. That sounds reasonable. >When I bought my Mountain HardDrive, the disk came with a head parking utility >for such a purpose. Now I'm wondering how do I UNPARK the hard disk to use it >again? Parking the heads just means moving them over a part of the disk that you don't care about (a place where you don't have any data stored -- usually the extreme inside (or outside) of the platter). This is done so that if the drive is disturbed in some obscure (or not so obscure) manner, and the heads somehow try to change some data, the data will be garbage anyway, and not something that you care about (usually the heads are "parked" over a cylinder which is not in the area for storage, so there's really no data there at all). You don't need to worry about unparking the heads: just use the drive as you normally would (pretent it's not parked), and the heads will return to the storage area to read data -- it just takes them slightly longer to do so. Anand.
ajmyrvold@violet.waterloo.edu (Alan Myrvold) (07/19/88)
In article <12184@agate.BERKELEY.EDU> cotner@bosco.berkeley.edu.UUCP (Carl Cotner) writes: >After some recent discussions and testimonials on the net, I've been >convinced that I should leave my PC and hard disk on 24 hours a day >to spare it the trauma of being powerred it on and off each time I >use the machine. > >Now I hear that I should park the heads of my disk whenever it is not in >use to prevent data corruption from a power surge. That sounds reasonable. I heard from an almost reliable source that parking the heads on a hard disk actually retracts the thingamabob that reads the disk. Acording to my source, the joint which retracts the thingamabob becomes sloppy after overuse, causing it to skip on the media surface, bringing up chips of the magnetic media which scrape the **** out of the drive as the head goes round. Now if this is true, and I wonder myself, then parking the heads of your disk daily (as opposed to only when it is shipped) actually dramatically decreases the life of your hard disk. The surges and transients due to turning the beast ON and OFF should be small enough to be handled by the computer. They also should be taken into consideration in the design of the PC. On the other hand, the surges that COULD result during a thunderstorm can ruin every part of your PC. I NEVER use my 'puter during a thunderstorm. Doesn't really make sense to do so. So it seems silly to leave a computer on unattended in all weather conditions - if there is no function that the computer is performing. And for people who use there computers at work - if you are in an industrial setting then you might be surprised by the power surges that occur at night. Basically I think it boils down to this : your computer equipment should live an honourable life if treated as it was intended to be used. By the time it breaks down due to normal use (assuming it survived the infant mortality period covered by warantee) it is probably time to buy a new system anyway. Alan J. Myrvold ajmyrvold@violet.waterloo.edu ---- So how much $$$ do these .sig's cost to send anyway?
bobmon@iuvax.cs.indiana.edu (RAMontante) (07/19/88)
A lot of people are telling the originator of this question that all he has to do is issue another instruction to unpark the drive head -- I've seen at least one head-parking program, named SHIP, that was intended to be used as the last operation before moving the computer. Because of this one- dimensional thinking, the program parks the head, and then goes into a tight machine-code loop in which it ignores minor irritants like the keyboard. The head could be easily unparked. You merely can't get the computer's attention to do so, so you have to reboot. A silly way to write the program, but there it is. There's a TSR called pdtimprk, by Dick Flanagan of this net, that works fine except for being automatic-only. When I DO want to park the head, power-down, and run for the storm shelter, I still need to use SHIP. No problem. (There's at least one more, called timepark, by Sanford Zelkovitz, which seems to work. Both are public domain, both come with .asm source, but pdtimprk is smaller and I'm memory-tight.) -- -- bob,mon (bobmon@iuvax.cs.indiana.edu) -- "In this position, the skier is flying in a complete stall..."
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (07/19/88)
In article <12184@agate.BERKELEY.EDU> cotner@bosco.berkeley.edu.UUCP (Carl Cotner) writes: Your next disk access should unpark the heads. There are several PD programs which park the heads after N seconds of non-use. I don't use any TSRs anymore, but I test one at some time and it seemed to work. | PS: I'm also leaving my monitor on 24 hours a day, but with the brightness | switch dimmed to pitch black, operating under the same assumption that | transients during power on is not good for the monitor either. Is this | a reasonable assumption, or should I just switch the monitor off? I definitely wouldn't cycle power on the monitor during the day, I would shut it down over a weekend (unless you're going to use it). I personally power down my monitor every night, but the rationale for this is primarily that this particular type of monitor has been know to burst into flames at out site. The one I'm using has burned twice, although it hasn't actually had flames coming out of the case yet. Mono monitors may be more sensitive to phosphor burn than color and should be turned down when not in use. There are several programs which do this after N sec on non-use. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
jamesa@amadeus.LA.TEK.COM (James Akiyama) (07/20/88)
In article <12184@agate.BERKELEY.EDU>, cotner@jif.berkeley.edu (Carl Cotner) writes: > After some recent discussions and testimonials on the net, I've been > convinced that I should leave my PC and hard disk on 24 hours a day > to spare it the trauma of being powerred it on and off each time I > use the machine. > > Now I hear that I should park the heads of my disk whenever it is not in > use to prevent data corruption from a power surge. That sounds reasonable. > When I bought my Mountain HardDrive, the disk came with a head parking utility > for such a purpose. Now I'm wondering how do I UNPARK the hard disk to use it > again? > > As far as I know, I have to turn off the PC and turn it back on > in order to bring up the hard disk. However this this seems to defeat the > purpose of leaving the computer on continuously to save wear and tear on > the hard disk. Can anyone set me straight? Is there a utility to unpark a > parked disk? > > Thanks for any advice and input. > > cc > > PS: I'm also leaving my monitor on 24 hours a day, but with the brightness > switch dimmed to pitch black, operating under the same assumption that > transients during power on is not good for the monitor either. Is this > a reasonable assumption, or should I just switch the monitor off? First, a few notes about parking disk drive heads. The IBM PC/AT (not sure about PC's) contain the landing zone information as part of the information associated with the drive type table. The AT sends the fixed disk to the specified track when requested to park. Note that drives will vary in the method or need to park them. Most of the "voice coil" drives self-park upon power down and may not have a landing zone accessible during operation. Voice coil drives also tend to "lose" their track information when parked (otherwise it would be necessary to record track information in the parking zone--a no no). This requires them to perform a recalibrate and seek to zero upon "unparking"--both require a considerable amount of time. Note that some voice coil drives (e.g. Maxtor 1140) DO NOT SUPPORT BUFFERED SEEKS DURING THE INITIAL RECALIBRATE AND SEEK TO TRACK ZERO. In the case of the Maxtor drive, buffered seeks during the recalibrate and seek to zero may cause a high-speed crash at cylinder zero, damaging the head assembly. Note that Maxtor explicitly warns about this in their OEM manual. Because of this the initial "unparking" can be a relatively slow process. Other drives (the Miniscribe 8425 is an example) requires a specific cylinder to guarantee parking. In the case of the Miniscribe 8425 you must send the drive to cylinder 663 to park it--any other cylinder (higher or lower) will result in a seek error with the head generally going to a random location. Since many PC vendor's only worry about matching the drive type number to the disk's number of heads; number of cylinders and (hopefully) the write precompensation cylinder; and often times do not worry about the landing zone, a park utility may not actually park your drive. Some park utilities seek to the last cylinder location and consider the heads parked. This is not a valid park, in most cases. Although it is true that DOS does not use the last cylinder, other operating systems may (e.g. I believe Unix places the bad cylinder table there). Also the physical head is much larger than one track--a crash generally wipes out all neighboring cylinders as well (I've found tracks 50 cylinders away damaged). In fact, it is generally the cylinders under the edge (and not the center) of the head that are most likely to be damaged. Most drive manufacturers actually park the head many cylinders (30-50 cylinders) away from the data region. As far as leaving a PC on or turning it off, I believe that this depends a lot on the duration the equipment is going to be idle, the system configuration, and the design of the power supply. Power supplies which have soft start circuitry and a controlled output ramp during power-up, are much less stressful on the electronics (and themselves), then one's that do not. Also note that some PC's are not adequately cooled. These PC's may overheat if left on indefinitely, especially in a building where the air-conditioning is turned off during the weekends. Note that most PC's (at least IBM's) are designed to operate at temperatures where humans are comfortable. They are not designed to run in an unheated or excessively hot environment. In a PC, the fixed disk and monitor are the two most likely parts which would "wear out" if left on. In the case of the monitor, this can be helped by either turning down the brightness or using a blanking utility. Note that this prevents the phospher from becoming "burned" but does not eliminate wear on the cathode gun. Over a long term, this may result in the CRT becoming dim as the tube begins to "wear out". In the fixed disk the normal idle wear process is generally associated with the spindle motor and spindle bearing. I have found at work, that drives will tend to wear out in about 1 to 2 years if left on continuously (although these figures are improving with the newer drives). As far as my personal PC's, I generally power them up when I need them, then power them back down before going to bed. Since I am now looking into being able to do remote logins I may have to change this a bit. Right now I'm looking at building some circuitry which allows remotely powering down/up the fixed disk under software control. As far as the monitor, I will probably power it down when I'm not present (I never did trust any unattended CRT). The rest of the PC will remain powered up constantly. I'm not entirely sure this is the best approach, but, in my opinion, it is at least reasonable. Oh, I should mention that these opinions are my own and not part of Tektronix. As far as the fixed disk stuff, I'm fairly sure most of it is accurate since part of my job description at Tek is to evaluate fixed disk for our product lines. We generally perform extensive burn-in and environmental testing before qualifying anything; unfortunately, most of the resulting data is considered company confidential. Hope this helps. James E. Akiyama jamesa@amadeus.LA.TEK.COM UUCP: ....!tektronix!amadeus!jamesa ARPA: jamesa%amadeus.LA.TEK.COM@RELAY.CS.NET
mikes@mntgfx.mentor.com (Mike Stanbro) (07/20/88)
From article <12184@agate.BERKELEY.EDU>, by cotner@jif.berkeley.edu (Carl Cotner): > After some recent discussions and testimonials on the net, I've been > convinced that I should leave my PC and hard disk on 24 hours a day > to spare it the trauma of being powerred it on and off each time I > use the machine. > Here's a wild thought I had several months ago but never pursued it because it seemed a bit risky. There are two voltages to hard disks: +5V and +12V. The +5V powers all of the electronic circuits, the +12V powers the spindle motor and actuator motor or coil. If you shut the +12V off and leave the +5V on, the spindle motor will shut down but the disk remains "intelligent" and will continue normally after the +12V is reapplied and the platters spin back up to speed. What do you think about a "black box" that plugs in-between the hard disk and the power supply cable and controller cables. My idea is to have a timer in the black box that senses the select signal going to the hard disk. As long as the select signal is toggled every now and then, the black box does nothing out of the ordinary. If the select line is inactive for more than a pre-established cut-off period (maybe 2 hours), the black box cuts off the +12V to the spindle motor to save wear on the bearings of the spindle and the spindle motor. But wait ... there's more ... when the select line goes active again, the black box reapplies the power to the motors and the disk spins back to life. I tried this with a manual switching setup. The only oddity is that DOS times-out waiting for the hard disk to respond and issues the familiar message you have seen from floppy drives: "Drive not ready: Abort, Retry, Ignore". If you wait for a second or two until the drive is at full speed, then issue a "retry" response, everything seems to work great. Well guys ... is that a wild idea or what? Mike Stanbro, Research Engineer (503) 626-1437 Mentor Graphics Corp., 8500 SW Creekside Place, Beaverton OR 97005 ...!{sequent,tessi,apollo}!mntgfx!mikes OR mikes@pdx.MENTOR.COM These are my opinions, & not necessarily those of Mentor Graphics. -- Mike Stanbro, Research Engineer (503) 626-1437 Mentor Graphics Corp., 8500 SW Creekside Place, Beaverton OR 97005 ...!{sequent,tessi,apollo}!mntgfx!mikes OR mikes@pdx.MENTOR.COM These are my opinions, & not necessarily those of Mentor Graphics.
pavlov@hscfvax.harvard.edu (G.Pavlov) (07/20/88)
In article <7837@watdragon.waterloo.edu>, ajmyrvold@violet.waterloo.edu (Alan Myrvold) writes: > I heard from an almost reliable source that parking the heads on a hard > disk actually retracts the thingamabob that reads the disk. Acording to > my source, the joint which retracts the thingamabob becomes sloppy > after overuse, causing it to skip on the media surface, bringing up > chips of the magnetic media which scrape the **** out of the drive as > the head goes round. > Good thing that none of the hard disks in our machines (up to 5 yrs. old, parked daily) ever heard of this problem... greg pavlov, fstrf, amherst, ny
demoedf@iitmax.IIT.EDU (ed federmeyer) (07/20/88)
I thought this might be of interest to you... I have a friend who has a hard drive in his PC, and he has it set up so that if you don't access the hard drive for a certain ammount of time (a few seconds for example), the read/write head is sent out to the last cylinder. That way, even if you ARE using your computer and you get some power glitch you will be okay. Offhand I don't remember the name of the software, but if there is enough interest, I will find out and post the name to the net. I find it hard to believe that turning a PC on and off every day can be harmfull... Even in the long run. I had a (what many of you would call a "wimpy, toy") Commodore 64 for maybe 5 years or so until I "upgraded" to a PC clone. I used to turn that sucker on and off HUNDREDS of times a week! (Most C-64 software, once started, will only be stopped by shutting the machine off). Well, I never did have any trouble with it, and when I bought my PC clone, I sold the '64 to a friend who is still happily using it. My Atari 2600 (I can't even remember how old it is... but it is one of the real old ones) still works! I even have, and use the ORIGINAL joysticks that came with it. (If you are not up an video game machines, let me tell you that many companies made some bucks selling replacement joysticks for that machine!) The moral of all this is that if you take care of your "stuff" (Electronic, or otherwise) it will last along, long time. (Assuming it works when you first get it! :-) Take Care, Ed Federmeyer
davidsen@steinmetz.ge.com (William E. Davidsen Jr) (07/20/88)
In article <1988Jul19.153220.854@mntgfx.mentor.com> mikes@mntgfx.mentor.com (Mike Stanbro) writes:
Here's a wild thought I had several months ago but never pursued it
because it seemed a bit risky. There are two voltages to hard disks:
+5V and +12V. The +5V powers all of the electronic circuits, the +12V
powers the spindle motor and actuator motor or coil. If you shut the
+12V off and leave the +5V on, the spindle motor will shut down but
the disk remains "intelligent" and will continue normally after the
+12V is reapplied and the platters spin back up to speed.
A bit risky indeed. Depending on the disk design it could be a small
problem of a large one. Consider the following disk types.
Head floats on air, lands at powerdown:
Stopping the rotation would cause the heads to land every time.
Unless they were on the landing zone you could lose data. Most cheap
disks work like this, the only thing which keeps the head up is the flow
of air caused by disk rotation.
Head floats on air, lands on powerdown, parks on powerdown:
These disks retract the head to the landing track before it
slows down enough to land the head. Cutting the motor power MAY park the
heads, but I wouldn't bet my disk on it.
Head normally retracted, floats on air:
These disks retract the heads on powerdown, and only after the
disk is at speed do they move the head toward the platter to float on
the air cushion. This is usually found on top of the line drives. I
wouldn't bet that the motor power controls the heads, it might just be
the +5 for the electronics. In that case the heads would land, and the
head design wasn't intended to land... ever.
You have an interesting idea, something like the opwering down of the
5-1/4" disks. Without having it built into the drive I think that there
is a good chance of disk damage, depending on the type.
Disclamer: my little list of disk types is incomplete and simplified,
don't (a) use it for more than examples, or (b) flame me for not being a
treatise on hardware.
--
bill davidsen (wedu@ge-crd.arpa)
{uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -mejohn@wa3wbu.UUCP (John Gayman) (07/21/88)
In article <7837@watdragon.waterloo.edu>, ajmyrvold@violet.waterloo.edu (Alan Myrvold) writes: > I heard from an almost reliable source that parking the heads on a hard > disk actually retracts the thingamabob that reads the disk. Acording to > my source, the joint which retracts the thingamabob becomes sloppy > after overuse, causing it to skip on the media surface, bringing up > chips of the magnetic media which scrape the **** out of the drive as > the head goes round. > I beleive what your source might be referring to is that some very large drives, especially high capacity 8" drives actually "cam" the heads up off the platter in the "parked" position. You won't find very many of the 5 1/4 hard drives that most people use with this type of actuator. I could be made to beleive that repeatedly "loading" and "unloading" the heads could eventually crash or pit the platter although this in itself would be rare. Most of the drives in use in PC's and Mini's are built in such a way that the heads *never* actually leave the platter ---- ever. Whatever the positioning mechanism, be it servo motor or voice coil, the heads never leave the platter. On these drives when they are in the "parked" position, it simply means that the heads have been placed over a cylinder that has been designated as the "landing zone". The idea here is that if the disk takes a shock (like in shipping) and scratches or otherwise harms the disk platter, the effected area will be the "landing zone" and not some area of the disk where good data resides. If you don't park the drive, then the heads will basically stay positioned over the cylinder they were last at (at least with servo positioners). The exception here is with a lot of the "voice coil" positioning systems. Most of these are auto-parking. When you turn the drive off, you will hear a mild "clunk", this is the head mechanism being tossed out and "latched" at the landing zone cylinder, which is usually all the way towards the inside closest to the spindle. Once powered up, the selenoid energizes and allows the head assy to return to its position at track zero, re-calibrate or do whatever else it wants to. With this in mind, I can see no reason why "parking" a disk would be harmful. It simply means the heads stay positoned in the landing zone and not some random data cylinder. By design, you normally do not format out to, or use the landing zone cylinder. I hope this has cleared up some of the questions anyway. This sure is a hot topic on the net every couple months. :-) This and twisted disk cables. :-) :-) John -- John Gayman, WA3WBU | UUCP: uunet!wa3wbu!john 1869 Valley Rd. | ARPA: wa3wbu!john@uunet.UU.NET Marysville, PA 17053 | Packet: WA3WBU @ AK3P
pjh@mccc.UUCP (Pete Holsberg) (07/23/88)
In article <1310@iitmax.IIT.EDU> demoedf@iitmax.UUCP (ed federmeyer) writes:
...I find it hard to believe that turning a PC on and off every day can be
...harmfull... Even in the long run. I had a (what many of you would call a
..."wimpy, toy") Commodore 64 for maybe 5 years or so until I "upgraded" to
...a PC clone. I used to turn that sucker on and off HUNDREDS of times a week!
Perhaps the C-64 had all its chip soldered in place? Thermal cycling
can make a chip walk out of its socket, given enough cycles. Also, the
"strain" on any motored devices occurs during power-up, power-down, and
changes in the load. A motor will spin nicely almost forever.