Talk:Hard disk drive/Archive 1

message: I have no idea why the article claimed that MFM was invented for floppy drives.  As far as I've been able to determine, MFM was first used on the IBM 3330 in 1971.  The 3330 was most certainly NOT a floppy drive.  The first use of MFM for a floppy drive appears to have been the IBM 53FD drive, introduced in 1977.  --Brouhaha 08:04, 3 Sep 2004 (UTC)
thread_title: MFM History

message: There's nothing written about the damage to hard disks: we should have at least a cursory explanation of the terms MTBF (mean time before failure), bad sectors/blocks/clusters, BBR (bad block relocation), handling by software and by hardware, hot swapping, something about refurbishing... --Joy [shallot] 14:29, 27 Sep 2004 (UTC)
replies: text: Repeated use of specific sectors is not a common failure mode.  The only thing similar is a particular use pattern may expose some design flaw that wasn't that obvious before.  --A D Monroe III 21:39, 20 January 2006 (UTC)
thread_title:  damage 

message: "Some modern drives include flying height sensors to detect if the pressure is too low, and temperature sensors to alert the system to overheating problems."
I do not believe that as of today, April 2005, there are any hard drives that have an altitude sensor as these are still to costly. Every modern drive has a temperature sensor. Channel parameters are typically adapted to the measured temperature. BruceSchardt
An altitude sensor is not necessary to detect flyheight change—there are other methods of doing so.  Of course, the statement above is somewhat misleading.  GMW 15:31, 6 February 2006 (UTC)
thread_title:  Altitude Sensor? 

message: I changed the discussion of startstop or CSS testing because the statement that 50% of the drives fail at 50,000 cycles is not correct. Typical specification for a desktop harddrive is 50,000 cycles. However this is not a mean time (cycles) till failure specification. This is a specification that all drives are supposed to achieve without failure. In typical testing a population of several hundred drives are contact-start-stop (CSS) tested for >100,000 cycles. No failures caused by the head-disk interface are allowed at less then 50,000 cycles. Testing for more then 50,000 cycles insures that the HDI design has margin. In proof, the Maxtor Diamondmax 10 hardrive specifies Start-Stop cycles at >50,000 min. Notebook hard drives are all load-unload designs that never park the heads on the disk, instead the heads are unloaded onto a ramp. This is done to increase the magnitude of non-operational shock that the drive can withstand.
BruceSchardt  RESEARCHER:John Raineil Bayani
----
The article currently says
: Most manufacturers design the sliders to survive 50,000 contact cycles before the chance of damage on startup rises above 50%. ... the Maxtor DiamondMax series of desktop hard drives are rated to 50,000 start-stop cycles. This means that no failures attributed to the head-disk interface were seen before at least 50,000 start-stop cycles during testing.
This makes it sound like Maxtor uses a different, more stringent test, and that their hard drives (or at least the sliders) are more reliable than "most manufacturers".
Is that really true?
I wish I had a reference that explained what is really meant by "at least 50 000". Does it mean that after 50 000 cycles, at least half the drives still worked? Or does it mean that after 50 000 cycles, *all* the drives still worked?
--DavidCary 05:59, 1 December 2005 (UTC)
thread_title:  Start Stop CSS Testing 

message: I don't wish to rain on your parade but hard disks crash no matter what technology has been produced to prevent this.. I would wish that labels be put on iPod's to notify the users of the iPod's that in certain ccircumstances jostling the player around could crash the hard disk and render the player useless.. Maybe someone can tell me differently.. 
--Rofthorax 08:13, 15 August 2005 (UTC)
replies: text: Do not degauss your hard drive. --Ihope127 18:29, 16 August 2005 (UTC)

text: Well, that's not entirely true.  HDDs made for portable CE devices typically have a shock sensor or drop sensor that allows the firmware to detect if the device has been jostled or chucked toward the ground at high velocity.  The firmware then unloads the heads.  (On the other hand, what happens after the drive bounces off the ground is an entirely separate concern!)  Furthermore, portable music players usually buffer data in memory and then unload the heads so as to minimize the risk when the people in those iPod "silhouette" commercials do their shimmy.  Of course HDIs are caused by other mechanisms as well, such as particulate contamination hitting the head or from deformation of the ABS during start-stop.  Hey, no technology's perfect, especially in the volumes HDDs are produced in.  GMW 18:05, 4 February 2006 (UTC)
thread_title:  Dangers 

message: Hard disk == the spinning CD-like thingy
Hard disk drive == the hardware that reads and writes to the hard disk
just thought I'd point it out :)
:Semantics, semantics =)  The old IBM Storage Tech term for HDDs is "file".  Veteran engineers still use the term, but newer engineers just say "drives".  "HDD" is too unwieldy.  (I suppose I'm a bit surprised that no one from Seagate has adjusted the spellng of "hard disk" to be "hard disc", which they seem to prefer.)
:HDD media isn't really CD-like, since the substrate is aluminum or glass and not polycarbonate plastic.  Nor does it exhibit the interference spectrum, as there are no pits and lands; an HDD platter actually looks like a mirror because of its exteme flatness and plated magnetic surface.  One of my coworkers keeps a 2.5" disk on his desk propped up by one of those binder clips (black metal spring clip with chrome latches) for preening =)
:I do agree, though, that this article should be called "Hard disk drive" rather than "Hard disk", as that's technically more correct.  GMW 16:52, 25 March 2006 (UTC)
replies: text: Perhaps silence can be assumed to be passive agreement? Ardric47 00:41, 16 April 2006 (UTC)
thread_title:  Hard disk != Hard disk drive 

message: The "Mechanics" part of this article is full of repeats. Somebody should clean it up. --Nappilainen 20:12, 26 January 2006 (UTC)
thread_title:  Rewrite 

message: 2005 - 1 TB hard drives
Any references to this? Last Avenue 00:52, 27 January 2006 (UTC)
thread_title:  2005 - 1 TB hard drives 

message: I removed the sentence and the section regarding derivative technologies.  The sentence was poorly written and confusing.  That could be fixed, though.  The real sticking point is the lack of references or citations to support this allegation.  If it's true that floppy disks and CD-ROMs are derivatives of hard disk technology then this fact certainly needs to be mentioned - with supporting references.  --ElKevbo 14:39, 2 February 2006 (UTC)
thread_title:  Derivative Technologies