PAX@PSUVMA.BITNET (11/17/86)
I'm thinking about putting hard disks in my PC-6300's. They currently have
2-360k floppies. My first question is should I go with AT&T hard drives or
a third party manufacturer. I've heard about problems with AT&T's drives.
My second question is terminology. I've talked to some people, and they said
I should look into "plated" disk drives, and ones that have "disk parking".
These terms are foreign to me, so if you know what they are, please let me
know.
What do you think about half-height hard drives over 3-1/2" slot hard
disks?
Please respond to this newsgroup, or to me direct E-mail.
Bitnet: FIB @ PSUVM
O05 @ PSUVM
Glenn S Piper
Penn State University
Berks Campus
RD#5 Reading, PA 19608
(215)320-4819merlin@hqda-ai.UUCP (David S. Hayes) (11/18/86)
In article <8519PAX@PSUVMA>, PAX@PSUVMA.BITNET writes: > My second question is terminology. I've talked to some people, and they said > I should look into "plated" disk drives, and ones that have "disk parking". > These terms are foreign to me, so if you know what they are, please let me > know. Plated: Refers to thin-film plated platters. This is a method of depositing an extremely thin magnetic layer onto the aluminum disk platters. A thin-film platter has a higher data capacity than an equivalent conventional platter. This is not really a user-visible feature, other than through the higher capacity. Disk Parking: On a winchester disk, certain cylinders are reserved "landing areas" for the heads. The head sits over these cylinders when the drive is spinning up to speed, or spinning down after being turned off. Because the drive is not operating at full speed, the heads will actually be in contact with the platters during this process. These areas are subject to extra wear, from physical contact with the heads, and cannot be used to store data. The heads should be moved to the landing area before powering down the drive. On cheap drives, you must run a program to do this. More expensive drives do this automatically. Generally, these more expensive drives also are better constructed, may have faster access times, have better head positioners, braking systems... If you opt for a drive without this feature, and forget to run the parking program before shutting down, you *WILL* damage your drive. It may take several occurrances before you start losing files, but every shutdown without prior parking will decrease the reliability of your drive.
psfales@ihlpl.UUCP (Peter Fales) (11/19/86)
> The heads should be moved to the landing area > before powering down the drive. On cheap drives, you > must run a program to do this. More expensive drives do > this automatically. > > If you opt for a drive without this feature, and > forget to run the parking program before shutting down, > you *WILL* damage your drive. It may take several > occurrances before you start losing files, but every > shutdown without prior parking will decrease the > reliability of your drive. This is news to me, and if drives with this (mis)feature are commonly in use it is probably something that should be more widely known. Most personal computers I am familiar with have a utility for parking the disk heads, but the documentation generally indicates that the heads only need to be parked if the computer is going to be moved. Does anyone have more information on what drives do and do not require explicit parking before shutdown? Pete Fales ihnp4!ihlpl!psfales
cej@ll1.UUCP (One of the Jones Boys) (11/20/86)
- > If you opt for a drive without this feature, and - > forget to run the parking program before shutting down, - > you *WILL* damage your drive. It may take several - > occurrances before you start losing files, but every - > shutdown without prior parking will decrease the - > reliability of your drive. - - Most personal computers I am familiar with have a utility for - parking the disk heads, but the documentation generally indicates - that the heads only need to be parked if the computer is going to - be moved. - - Does anyone have more information on what drives do and do not require - explicit parking before shutdown? - - Pete Fales The documentation does seem to be correct, and is in agreement with all documentation I have ever seen for winchester drives that don't auto-park. At one time I supported (installed/maintained) over 50 AT&T 6300s and IBM-PCs for a period of about a year and a half, and none of the drives were ever parked except to be moved. And in that time, other than infant mortality, we had only one failure of a drive that was related to the media or heads. So you can feel quite safe following the documentation. This time... :-) ...ihnp4!ll1!cej Llewellyn Jones
dw@rocksanne.UUCP (Don Wegeng) (11/20/86)
In article <1504@ihlpl.UUCP>, psfales@ihlpl.UUCP (Peter Fales) writes: > > The heads should be moved to the landing area > > before powering down the drive. On cheap drives, you > > must run a program to do this. More expensive drives do > > this automatically. > > > > If you opt for a drive without this feature, and > > forget to run the parking program before shutting down, > > you *WILL* damage your drive. It may take several > > occurrances before you start losing files, but every > > shutdown without prior parking will decrease the > > reliability of your drive. > > This is news to me, and if drives with this (mis)feature are commonly in > use it is probably something that should be more widely known. Most > personal computers I am familiar with have a utility for parking the > disk heads, but the documentation generally indicates that the heads > only need to be parked if the computer is going to be moved. I disagree with Peter Fales. Most inexpensive (and maybe expensive too) winchester disk drive manufacturers coat their platters with a lubercant so that when the heads land on the surface of the platter it will not cause damage. If you were to always power down the drive with the heads over the exact same cylinder then you might over time wear through the lubercation, at which point you would start damaging the platter surface (read "head crash"). Most personal computer usage patterns do not result in this condition. In general I believe that it is a good practice to park the heads before you power down a computer, but I don't consider it an absolute necessity. One thing that *is* worth considering is that PC component manufacturers design their products for a five year life time, and in fact have no idea what failure modes are to be expected after that time period. It probably makes sense to be nice to your disk drive. /Don -- "So lie to me, but do it with sincerity." --M. L. Gore (Depeche Mode) Don Wegeng Wegeng.Henr@Xerox.COM seismo!rochester!rocksanne!dw
jkg@gitpyr.gatech.EDU (Jim Greenlee) (11/20/86)
In article <459@ll1.UUCP> cej@ll1.UUCP (One of the Jones Boys) writes: >- Most personal computers I am familiar with have a utility for >- parking the disk heads, but the documentation generally indicates >- that the heads only need to be parked if the computer is going to >- be moved. > > The documentation does seem to be correct, and is in >agreement with all documentation I have ever seen for winchester >drives that don't auto-park. > > At one time I supported (installed/maintained) over 50 AT&T >6300s and IBM-PCs for a period of about a year and a half, and none >of the drives were ever parked except to be moved. And in that >time, other than infant mortality, we had only one failure of a >drive that was related to the media or heads. So you can feel quite >safe following the documentation. This time... :-) When I purchased my PC 6300, I was specifically told NOT to park the heads with the DOS 3.1 "SHIP" utility. The salesman claimed that it would cause problems, but did not elaborate. Any reason why I would have been given this advice? (the drive is an ST-235, I believe). Jim Greenlee { What follows are blank lines so our stinking news system will take this article (something about including more lines than new lines) Please hit "n", or whatever, now } -- The Shadow...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!jkg Jryy, abj lbh'ir tbar naq qbar vg! Whfg unq gb xrrc svqqyvat jvgu vg hagvy lbh oebxr vg, qvqa'g lbh?!