Talk:Hard disk drive

Dead References

Reference 63 is now 404. Please find additional sources to support the notion of a capacity ceiling. — Preceding unsigned comment added by 46.7.165.130 (talk) 22:14, 10 December 2011 (UTC)

I used the site search facility and repaired the link. It is common practice to either tag dead links with {{dead link}}, or make a good faith attempt to find out if the page was moved and update the link. But thanks for letting us know. What really needs to be done is permanent archiving of pages that are likely to disappear. This procedure is explained at Wikipedia:Using WebCite. Elizium23 (talk) 02:45, 11 December 2011 (UTC)

"In machine-readable data storage..."

Referring to this edit and comment, I think "machine-readable data storage" will be more puzzling to the hypothetical farmer from Africa than "hard disk drive" without a qualifier. It also struck me that the lede took a long time to get around to stating what a HDD is for. (My favorite uncivil editor is fond of ridiculing articles that never, or at least take a long time to, point out what the subject of the article is used for.) By adding "for storing and retrieving ..." to the end of the first sentence, we address both issues in a way much more quickly understood, not to mention far less awkward and stilted, than "In machine-readable data storage...".

Yes, there are uses for hard drives other than computers (consider the Ampex HS-100, which used a hard drive to store analog signals, and with the head contacting the surface besides) but again, it's just the lede. It's enough to say "digital information, primarily computer data". Examples of other uses can appear later. We don't need to mention the occasional analog hard drive here either. It is not the purpose of the lede to describe every exception and special case.

Speaking of which, I also removed some unnecessary detail (and a huge run-on sentence) from the lede. Jeh (talk) 00:17, 16 December 2011 (UTC)

I agree with Jeh's edits. Tom94022 (talk) 06:43, 16 December 2011 (UTC)

More on the lede

Tom94022, re your recent change to the lede... I appreciate the updated info but I think that's really too much very deep detail for the lede. Jeh (talk) 07:32, 16 December 2011 (UTC)

Hi Jeh, Are you talking about this change to the lead subsection of the Technology section? If so, I think I made it less technical by taking out MFM, GCR, etc and distinguishing between user data and the data as it is encoded onto the disk. I thought about using Morse code as an analogy but thought that would be TMI. My problems with the original version were the added tape analogy (IMO not a good one), the several obsolete codes that are just a form of RLL, the way recording was described (sequential changes in polarity versus transitions) and the lack of distinction between encoding and decoding, all of which I tried to fix. Take a hack at it yourself but please don't go backwards :-) Tom94022 (talk) 19:32, 17 December 2011 (UTC)

Rewrite Integrity Section

The Integrity section of this article has little to do with Integrity, something about Reliability and a lot about Head Crashes and their mitigation and they are all mashed together with little flow. The recent unsourced addition on [Modes of failure] didn't help. It needs a rewrite, rename and or split. I'll make a proposal here and perhaps sandbox the changes but I thought I would ask for comments before I do major surgery Tom94022 (talk) 19:43, 17 December 2011 (UTC) I thought about this over night and propose that the section be retitled Reliability with the following subsections

7. Reliability

1. Metrics
2. Modes of failure
3. Historical examples
4. Recovery from failures

All of the above would be developed from reliable sources such as the Google study, several papers on HDD reliability such those by Elerath, and web material from HDD companies and HDD recovery services. The stuff on head load/unload and landing zones would be moved to section 2. Any comments Tom94022 (talk) 17:41, 18 December 2011 (UTC)
I am now working on this in a sandbox. Contributions are welcome Tom94022 (talk) 19:47, 18 December 2011 (UTC)

If you look around on the websites of data recovery firms (bit dubious if those could be used as reliable sources), firmware corruption, especially corruption of the P-LIST and G-LIST, caused by firmware bugs seems to be a common cause for failure of modern drives. This isn't covered yet. —Ruud 23:35, 29 December 2011 (UTC)

using 4gb ram to a 500gb hard disk causes hard disk burn

hello i want to know that,using a 4gb ram to a 500gb hard disk causes the hdd to burn or not. my brother who had to be using a 4 gb ram to a 500gb hdd which burned a lot of times,thanks to the warranty,He got a new ones every time,so in addition he used to be using a cable connection to the desktop for tv,that time if the hdd burns he use to think that the voltage present in the cable cause that burning.and now he upgraded his hdd to 1tb now there is no burning of the hdd of the same company please help me with this — Preceding unsigned comment added by 117.200.98.44 (talk) 19:29, 29 December 2011 (UTC)

Highly unlikely. Likely causes include a bad power supply, a bad model hard disk (hard disk manufacturers sometimes produce models with above average failure rates), or just plain bad luck. In the future, please consider posting such questions at the Reference desk. —Ruud 20:06, 29 December 2011 (UTC)

IMO it is not possible for the DRAM to cause any failure of an HDD, period, much less causing it to "burn". Since the system now works with the same 4 GiB of RAM, the same power supply, the same cables and a new drive from the same manufacturer it sounds like just plain bad luck. The cable connections are the only thing that really changed as the drives changed and it is hard to see how they could cause a drive to "burn" - for example, I doubt if an intermittent power supply ground pin or wire would cause a drive to "burn". Likewise the drives are pretty robust so an intermittent power supply is liable to do a lot more damage to other electronics long before it "burns" the drive I vote for bad luck. Tom94022 (talk) 22:06, 29 December 2011 (UTC)

Hard disk drive "too technical"?

173.180.88.123 (talk) 23:40, 31 December 2011 (UTC)I would like to comment on the heading that states:

"This article may be too technical for most readers to understand. Please help improve this article to make it understandable to non-experts, without removing the technical details. The talk page may contain suggestions. (October 2011)"

This is a technical article, and is therefore "technical". As politically incorrect as it may be, there are many topics that when properly presented, will be beyond the scope of understanding for many readers. I found it quite interesting, there are numerous links, and if I don't understand something, I'll just have to look it up.

All disciplines of study have their own language or terminology that have a specific meaning for the discipline, but a very different meaning to those who have not been educated in the discipline. Replacing this specific terminology or language with simpler language so it becomes more "understandable" will only create ambiguity, and confusion for those who do understand the terminology.

There are no short cuts to learning or understanding.

I do not consider myself a "techie" or "geek", but the vast majority of computer users have very little knowledge about their systems. Some of my friends consider me an "expert", but compared to the real experts I have known over the years, I am not much more than a "newbie".

One of the best examples of misunderstood terminology can be drawn from statistics; accuracy and precision have very different meanings, but they are used interchangeably in common usage.

Trying to “dumb down” information or knowledge to the lowest common denominator leads to mediocrity, and is a disservice to those who have taken considerable time, often at considerable expense, to acquire their expertise.

Wikipedia should also be a source of information for those of us who willing to stretch our minds to acquire more knowledge.

Pablum is not the solution.

jloimand@telus.net

Agreed, we should take the tag down. If the IP tag bomber neither took the time to explain why he/she thought the article was "too technical" nor made any attempt to clean up examples then we shouldn't bother to give him/her too much credence. Tom94022 (talk) 23:48, 31 December 2011 (UTC)

Agreed and done. The IP's other contributions do not lend much credence to him or her either. Jeh (talk) 02:24, 1 January 2012 (UTC)

Failure modes and drive orientation

User Johnnynolan2 (contribs, talk) added a claim that vertically orienting a hard drive could contribute to failure. I have reverted this for these reasons:

• All Wikipedia content must be verifiable by being referenced to reliable sources. There was a source, but it's a self-published blog; those don't count.
• The claim is contradicted by information from hard drive manufacturers. They do recommend that the platters be within a few degrees of horizontal or vertical, but there is no recommendation against vertical.
• The claim on the referenced blog is unlikely in that it depends on the access arms simply moving in and out (like a piston). Rather, the arm assembly rotates around a pivot, in the manner of the tone arm on a record turntable. And, like a turntable arm, it is counterweighted on the other side of the pivot. Due to the counterweight, a vertical orientation does not cause gravity to pull the arms in or out. (Hey, the manufacturers did anticipate the possibility of vertical orientation!)
• The exact arm position is determined by the drive reading signal from the tracks and micro-positioning the heads for the best signal. The drives do not simply command the heads to move to a position and hope for the best. They used to do that (a couple of decades ago, using stepper motors) but no more. So even if gravity did exert an influence on the head position, it would be corrected by the drive.

I hope this adequately explains why I reverted these edits. Further discussion here, please, if anyone wants. Jeh (talk) 06:05, 7 January 2012 (UTC)

I've seen some pretty convincing diagrams that imply vertical mounting can significantly raise the number of seek errors (which would reduce performance, but not cause failure), but I don't think those were published on a reputable tech site. —Ruud 16:53, 7 January 2012 (UTC)

I agree with Jeh's analysis and support the removal. In modern HDDs the rotary actuators are balanced and the closed loop positioning mechanism can easily compensate for any residual force caused by any residual unbalance. I doubt if vertical mounting has any effect upon seek errors in modern drives. Tom94022 (talk) 17:54, 7 January 2012 (UTC)

I found an interesting forum thread [1]. According to manufacturers any the 6 orientations is fine although they usually make no comment on tilted ones or say not to mount them tilted (Hitachi). The thread itself is of course not a reliable source, but some of the sources they bases their conclusions on are. We should probably add something on this to the article. —Ruud 18:59, 7 January 2012 (UTC)

I suppose a single sentence someplace in the article that modern disk drives can be mounted in any orientation citing the references in the thread would be OK although I am not sure it adds much to this already overlong article. Regarding tilt - ever seen a prohibition on operating your laptop on your lap? FWIW, I'm typing this on an IBM T23 in an IBM docking station with a designed in tilt measured at about 3 degrees; this laptop came with and IBM now HGST soon to be WD HDD, so I suspect HGST's prohibition is not substantive :-). Tom94022 (talk) 20:04, 7 January 2012 (UTC)

Vertical and stranger orientations are quite common in servers, consumer electronics and external drives, so yes I completely agree there not going to be a problem with this. Still, orientation could perhaps affect temperature distribution, (platter) vibration and bearing load (all probably more in 3.5" drives than in 2.5" drives), so I wouldn't be surprised if this resulted in some empirically measurable performances differences from the drives having a harder time locking onto a track. But without any reliable sources confirming this, it shouldn't go into the article. Perhaps we should add a short section on "Mounting" and summarize manufacturer recommendations, discuss some industry practices, vibration in storage arrays (enterprise drives compensate for this) and perhaps a historical note on stepper drives? It surely is a point that seems to be discussed quite often. —Ruud 20:42, 7 January 2012 (UTC)

I suppose a single subsection with a single short sentence in section 5, Performance, would be more than enough. FWIW, IMO orientation would not substantively change temperature distribution, (platter) vibration and/or bearing load sufficient to cause any measurable change in seek performance or HDD reliability. Of the three it is true that orienting the long access of the drive with the air flow could produce a lower temperature rise but the difference in rise is small and at least some empirical studies have not shown any correlation between temperature rise and reliability. Since gravity is reasonably consistent even stepper motor drives were relatively immune to orientation so long as you didn't change the orientation after formatting. Open loop linear actuator drives (stepper and voice coil) couldn't be vertically mounted but most of them were so big they couldn't be so oriented. An interesting historical footnote, IMO, not worthy of mention. Tom94022 (talk) 22:54, 9 January 2012 (UTC)

New technology 4k sectors

I am was trying to get info. on the new hard discs where sector size has increased from 512 bytes to 4k per sector. While this information is available at https://en.wikipedia.org/wiki/Disk_sector amd preferably https://en.wikipedia.org/wiki/Advanced_Format somehow mention of this new technology is not there in the entire article. At the very least this should be mentioned giving link preferably to the wiki page on Disk_Sector. Shirishag75 (talk) 03:01, 10 January 2012 (UTC)

Please see 3.2 HDD formatting wherein it states, "Modern HDDs, such as SAS and SATA drives, appear at their interfaces as a contiguous set of logical blocks; typically 512 bytes long but the industry is in the process of changing to 4,096 byte logical blocks; see Advanced Format." I suggest that is enough for this article. Tom94022 (talk) 06:24, 10 January 2012 (UTC)

Recertification

---

relocated this section from first to appropriate time sequence on this talk page ---- Tom94022 (talk) 17:21, 17 January 2012 (UTC)

I'd like to see something in the article about recertification. Recently, previously used (presumably) hard drives are being sold as "recertified". Questions to answer include things like:

• Is there a standard meaning or process of recertification?
• What should the user expect as to lifetime or reliability of a recertified drive?
•  ??

Rhkramer (talk) 14:29, 17 January 2012 (UTC)

I don't see a need for such a section and unless there is a reliable source it would be impermissible OR any how. FWIW, based upon my understanding of the industry:

• Is there a standard meaning or process of recertification?

No. It depends upon the vendor of the recertified drive.

• What should the user expect as to lifetime or reliability of a recertified drive?

Disk drives are pretty reliable so you can expect the drive to outlive the warranty provided by the vendor but by how much is not predictable.

I wouldn't have too much problem buying a reconditioned or refurbished drive from an HDD vendor but I wouldn't trust anyone else. Tom94022 (talk) 17:21, 17 January 2012 (UTC)