Talk:Hard disk drive/Archive 6

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Archive 4

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Tom being disruptive again

I urge an adminstrator to read the summary by the uninvolved adminstrator and read how Tom was being disruptive in the section before the administrator stepped in. Then read how Tom is being disruptive again on exactly the same fact tag issue. Glider87 (talk) 02:40, 21 June 2009 (UTC)

I urge any admin who responds to focus on the more recent discussion, which has become an effort to develop a revision that justifies removal of the tag. If anyone is being disruptive here, it's Glider, who keeps posting without contributing anything constructive and has interfered by removing the passage under discussion without justification.Therealdp (talk) 04:34, 21 June 2009 (UTC)

As any admin who looks at your edit history will find it is you who is being disruptive because you just used several personal attacks. Also as I posted above there is justification for removing the offending content because the fact tag has been there fore quite some time and Tom has repeatedly failed to provide reliable sources related to the fact tag. As any admin will be able to see your account is new and has focussed on attacking me after it was me who showed Tom to be wrong in the first place. In Wikipedia terms that is known as a single purpose account attack account. Glider87 (talk) 12:23, 21 June 2009 (UTC)

Although I've been consulting Wikipedia for awhile, mainly to bring my computer-related knowledge up to date, it was only recently that I had a question (concerning the SMTP article) and created an account so I could post. Later, when I read this article, I had a suggestion and a question, so I posted those. Tom asked my opinion about the earlier debate and I shared it, then thought of a solution and shared that, too. You made a remark about my post that I thought missed its point, so I replied. Since then, we've debated, but it's only my last post that you deemed a personal attack (and I've apologized about that in the other thread). So, although our exchange has (unavoidably) skewed a near-virgin account, it wasn't created for the purpose of antagonizing you or altering an article I hadn't even thought to read yet and hasn't focused on attacking you. I've no history with you and there's been no collusion or connection between Tom and I (other than what you see on this page), if that's what you mean to imply. I'm merely a newbie who's become interested in improving this (and another) aspect of the article and judged it appropriate to respond to you.Therealdp (talk) 22:07, 21 June 2009 (UTC)

With two editors, myself and Therealdp agreeing the paragraph should not be removed I have undone Glider87s deletion. Tom94022 (talk) 04:39, 21 June 2009 (UTC)

I have undone your change because you are editing against consensus as demonstrated by the administrator's comments. Glider87 (talk) 05:58, 21 June 2009 (UTC)

There seems to be unnecessary edit warring going on here and it must stop. I found a ref that seems to cover the fact tag. Am I missing something? What other statements are in dispute here?--agr (talk) 22:24, 22 June 2009 (UTC)

Tom is edit warring again because he refuses to provide any valid argument supported by cites to support his claims. I've removed the last attempt he made because the last time he tried to use that PDF it was consensus that the PDF does not support his claims. Glider87 (talk) 23:21, 22 June 2009 (UTC)

It takes two to edit war and in my opinion both of you need to back off. The ref you removed does support statements that sealed drives are used above 10,000 ft. Again let me ask what statements or claims are you disputing in your fact tag? --agr (talk) 23:52, 22 June 2009 (UTC)

Tom thinks "it is trivially obvious that ordinary hard drives can safely be used in flight" but the PDF he included does not support that claim because nowhere in the PDF does it state that ordinary hard drives can be safely used in flight. Tom has failed to take into account the changes in pressure, even in a pressurised cabin there is variation, humidity, temperature and vibration. Tom's claim is orginal research because it makes an non-trivial assumption about a technical subject, see the section titles "Synthesis of published material that advances a position". The PDF link he provided doesn't go into enough detail about sealed disks to be useful for the purposes of being a reference. However I did find a cite that goes into much better detail to replace his poorly sources cite. Tom has a long history of being disruptive on this topic, just look at the consensus that was reached a month of two ago on this talk page. So in reality I am not edit warring, instead I'm removing the obvious attempts by Tom to be disruptive and removing his vandalism of this topic. Glider87 (talk) 00:32, 23 June 2009 (UTC)

Having just been pinged by Tom for some reason, I have to back Glider87 up here. This insistence that non-trivial technical detail is obvious enough to repeat without reference has been a point of contention for years on this topic now, with strong consensus against Tom's position. I would remind all editors not to get into edit wars, but would also strongly recommend that the content in question is left off the article until reliable secondary sources are found for it, if ever. Chris Cunningham (not at work) - talk 01:00, 23 June 2009 (UTC)

Tom pinged you? Oh, he left a message on your talk page. Oh I see! :) I agree, I would support an RfC against Tom's behaviour. Anyway that is off topic. Back on topic, it is precisely the addition of unreferenced technical details to this article that I have issue with. You and I know the consensus is against Tom's point of view so that is why I also think the claim from the article should be removed, which is what I did. For example, once a reliable source was found by ArnoldReinhold (the breather holes technical detail) I am happy to see the removed text put back again. Glider87 (talk) 01:14, 23 June 2009 (UTC)

It seems to me that it's flat out wrong to claim that because hard drives operate to 10,000 ft and commercial aircraft cabins are generally pressurized to a lower altitude it is safe to operate laptops in aircraft. Hard drive altitude rating is not the only issue involved. A laptop's air cooling system, for example, becomes less effective as air density drops. It might, however, be reasonable to say that since commercial aircraft cabins are generally pressurized to a lower altitude, hard drives with a 10,000 ft pressure rating do not preclude safe operation on such aircraft. Or if that is too much of a WP:SYN, simply state that commercial aircraft cabins are generally pressurized to a lower altitude and let readers draw their own conclusion. Incidentally, in looking for refs, I noticed that some hard drive vendors are now offering "automotive" hard drives that, among other things, operate at higher altitudes, e.g. [1] which is rated to 5500 m (18000 ft). I think that might deserve a mention. --agr (talk) 04:52, 23 June 2009 (UTC)

Your example is not a particularly good one since the altitude of some cities is higher than the cabin altitude of commercial aircraft, implying there are cities where such laptops cannot safely be used. It is difficult to prove a negative, but do you really believe such a prohibition would seriously be allowed by any laptop manufacturer. My point has always been that safe useage is "trivially obvious" to anyone who has traveled in a commercial aircraft and observed the many users of laptops and the specific enabling of their usage in flight other than during landing and takeoff. I have yet to hear any argument against this. Tom94022 (talk)

For whatever my opinion's worth, the first suggestion is excellent and the second is acceptable, too.Therealdp (talk) 18:01, 23 June 2009 (UTC)

Does anyone object to my adding the first version to the article?--agr (talk) 10:59, 24 June 2009 (UTC)

Yes, I think it is too WP:SYN. It's probably best to leave out the "oh by the way it is safe to use drives on flights" stuff until we can find a concrete cite. Glider87 (talk) 14:07, 24 June 2009 (UTC)

I think you should add the first suggestion. That makes 3 for and 1 against, consensus? Tom94022 (talk) 17:33, 25 June 2009 (UTC)

Writing as an uninvolved (except for one recent minor merge) established editor, I am surprised to see this level of drama over what is probably seen by many as a relatively minor disk drive environmental issue. This is not a Palestine vs. Israel, Abortion, Sara Palin, Gun Control, Cold Fusion, or other controversial or battleground article. It's just an article on computer technology, a rather uncontroversial subject area. Unless one is arguing platform, operating system, or programing language religions, of course ☺. — Becksguy (talk) 18:08, 24 June 2009 (UTC)

It is more than what seems to be a small issue about a small bit of text. This is because Tom is claiming he doesn't need to produce a cite for a claim when he thinks his synthesis to advance a position "is trivially obvious", it is that issue that has generated so much debate. Of course the Wikipedia wide consensus is that Tom's point of view is wrong. Did anyone else notice Tom making this edit against consensus to restore the same claim about drives in flight with the comment "cite is not needed"? He then must have read all of the comments demonstrating how his point of view is completely wrong and then reverted himself six minutes later.Glider87 (talk) 02:28, 25 June 2009 (UTC)

Glider is partially correct, I thought he had made a contentious edit to the article and corrected it. I then read the discussion page and found some real discussion, specifically, agr's suggested alternatives and decided to think about them before fixing Glider contentious edit. Tom94022 (talk) 17:33, 25 June 2009 (UTC)

I'll pit the great debate on binary prefixes at WP:MOSNUM against Palestine vs. Israel, Abortion, etc. any day. But seriously, I've been trying to find a consensus here. I think my second suggestion, just mentioning aircraft cabin altitude pressure without drawing any conclusion would not violate WP:SYN. At for tom, I've warned him to stop making contentious edits without consensus. I hope we can find some consensus here and end this dispute amicably.--agr (talk) 15:47, 25 June 2009 (UTC)

I love all these warnings, as I said on my talk page, I have made no contentious edits to the article since my second removal of the fact tag on or about 14 April and I will be happy to defend what I have done. I do appreciate your starting some discussion. Tom94022 (talk) 17:33, 25 June 2009 (UTC)

Do we now have consensus to add:

Commercial aircraft cabins are generally pressurized to a lower altitude so that hard drives generally with a 10,000 ft pressure rating are not precluded from safe operation on such aircraft.

with no fact tag?Tom94022 (talk) 17:33, 25 June 2009 (UTC)

First, my apologies. I saw a recent edit from you and didn't notice that you had self-reverted. As long as everything stays on the talk page and we avoid name calling we're cool. As for your proposed language, I see two problems. First, Wikipedia should not say anything is "safe" without an attribution or, better, a direct quote. See WP:NOTMANUAL. Second is the "so" language that draws a conclusion. I've been looking at manufacturers' pages and they vary a lot. Apple rates its laptops to 10,000 feet. Dell says nothing. Both sell airplane power adaptors. I'd prefer to just say that hard drives are generally rated to 10,000 feet and commercial aircraft cabins are normally pressurized to a lower equivalent altitude, except when servicing an airport at higher altitude. Then readers can form their own conclusion, as WP:SYN recommends. --agr (talk) 19:55, 25 June 2009 (UTC)

I understand and accept yr concern about "safe" - see my proposal below. Tom94022 (talk) 23:43, 25 June 2009 (UTC)

Found this via a Google Scholar search. From the Journal of Military Electronics and Computing (cached version since I can't find direct link): [2]

Harsh: C4ISR Aircraft In-Cabin

Many C4ISR aircraft are wide-body platforms designed to carry large numbers of crew and large amounts of sophisticated equipment on missions. Examples of aircraft in this class are the E-3 AWACS, Airborne Stand-off Radar (ASTOR), or C-130, which functions in the C4ISR role in several variants. These aircraft present moderate levels of shock and vibration such as that from air turbulence, jet or turboprop engines and their spinning blades or propellers, and landing gear contact with a runway. Cabins in these aircraft are pressurized, typically to an altitude of 8,000 to 10,000 feet above sea level, and temperature controlled to enable the human crew to work comfortably. In-cabin use is a good example of an application where hard disk drives can be used. As long as the equipment is mounted inside the cabin, hard disk drives are able to operate because the required pressurization needed to float the drive head exists, and the ambient temperature is above freezing. With steps to isolate the hard disk drives from the moderate amounts of shock and vibration encountered during flight, they can function very reliably.

I think that is probably sufficient to include the statement in the article about using laptops with hard disk drives in normal pressurized aircraft cabins (in-cabin environment). Note: C4ISR = Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance. See: C4ISTAR — Becksguy (talk) 21:20, 25 June 2009 (UTC)

Can you find a link to something that doesn't include Google cache? That cite is probably going to disappear soon and isn't very good for verifiability. The cite also mentions vibration/shock and isolation from the drives to enable them to operate reliably which refutes Tom's claims on the subject. Glider87 (talk) 22:59, 25 June 2009 (UTC)

So with or without a fact tag, how about:

Ordinary HDDs do not have flying problems in commercial aircraft because the cabin is pressurized to an altitude that is less than the HDD's specified maximum altitude.

This combines the two sentences that Glider has unilaterally obliterated. Note that the article I cited states "typical hard drive specifications are ... Max operating altitude 10,000 ft". Tom94022 (talk) 23:43, 25 June 2009 (UTC)

That still violates WP:SYN. I did not unilaterally obliterate anything either, I removed your attempts to be disruptive and removed text that doesn't have valid supporting cites. The Blattau cite is useless because it does not support the claim you are making because as ArnoldReinhold says above it is "flat out wrong...". So Tom a challenge for you, prove me wrong by showing the exact place in the Blattau cite where it says clearly that "Ordinary HDDs do not have flying problems in commercial aircraft" like you claim. The cite of course does not therefore what you write violates WP:SYN. End of story. Now then the cite from Becksguy is good to know but it is a link to the Google cached version which will probably disappear quite soon so a more permanent link would be useful. Glider87 (talk) 23:59, 25 June 2009 (UTC)

Found the direct link:

Boham, Tom (July 2007). "Storage for Harsh, Harsher and Harshest Mil Environments". Journal of Military Electronics and Computing (COTS Journal). Retrieved 2009-06-25.

— Becksguy (talk) 00:34, 26 June 2009 (UTC)

Good! All this time Tom has been claiming "typical hard drive specifications are ... Max operating altitude 10,000 ft" or "Ordinary HDDs do not have flying problems in commercial aircraft because the cabin is pressurized to an altitude that is less than the HDD's specified maximum altitude" i.e. Tom has completely failed to represent the effects of vibration in any of his claims. However the cite from Becksguy proves that Tom's point of view is wrong because the cite clearly states "with steps to isolate the hard disk drives from the moderate amounts of shock and vibration encountered during flight, they can function very reliably." i.e. Pressure, temperature and vibration are important factors. This is a good example of why we cannot rely of what Tom thinks is "trivally obvious" because Tom's synthesis of material has completely forgotten the effects of vibration and as the cite seems to show the effects are important things to consider for drives to function reliably. If we had just believed Tom and let him keep claims in the article that did not have a valid cite then the information in the article would be incomplete and unverifiable. Tom has still yet to prove exactly where in the Blattau cite it says says clearly that "Ordinary HDDs do not have flying problems in commercial aircraft" like Tom claims. There is just one point of order I feel I must point out: The article cited is written by "Tom Boham, vice president for business development, VMETRO" and the article does make advertisement like claims for VMETRO SANcab and other VMETRO products. It is a bit like a paid for advertisement like appears like a news story. So I think the cite is a bit like a primary reliable source rather than a reliable secondary source, can we try to find a reliable secondary source that says something similar to this seemingly primary source? Glider87 (talk) 01:54, 26 June 2009 (UTC)

It is hard to see the relevance of an article in the Journal of Military Electronics and Computing discussing C4ISR about JBOD storage in military aircraft has much to do with use of HDDs in laptops in a commercial aircraft. The current proposed sentence is not WP:SYN since it combines three reliably documented facts with mathematics:

HDDs rely on air pressure inside the the enclosure to support the heads at their proper flying height.
HDDs are typically specified to operate at up to 10,000 ft.
Commercial aircraft cabins are pressurized so that the altitude typically does not exceed 8,000 ft.
8000 < 10000

HDDs have many physical specs, dry and wet bulb temperature, temperature gradient, humidity, shock, vibration, altitude, RFI/EMI, amongst others any one or all of which may be exceeded in any operating environment, including aircraft. The current proposed sentence only deals with altitude and raising any or all of these is just a strawman's argument. Glider never has proposed anything constructive and I suppose we will have to see if we can come to a consensus not withstanding his obstructionism. Any one have any comment on this:

Ordinary HDDs do not have head flying problems in commercial aircraft because the cabin is pressurized to an altitude that is less than the HDD's specified maximum altitude.

with or without fact tags? Tom94022 (talk) 22:36, 27 June 2009 (UTC)

It violates WP:SYN because you combine those three facts you just mentioned and your cite does not combine and explicitly state those three facts can be combined in such a way. WP:SYN is all about not combining facts on your own because you are not an expert on the subject and you need to provide cites in the form of reliable secondary sources that demonstrate that combination of facts. Just because you think it is trivially obvious does not mean you can include it in the article because that does violate WP:SYN and also WP:RS. Read WP:SYN again to see exactly why your point of view is against consensus. Everyone else is telling you that it is against WP:SYN so just drop it, if you do not drop it then that will be in violation of WP:POINT. You are the person who is being disruptive because you repeatedly misrepresent the truth and now you are personally attacking me again just because I make stronger arguments. Given the recent comments by others [3] [4] [5] you have two choices here, provide cites for the claims you want to include in articles or stop edting before you get blocked for disruption. This has gone way beyond adding something to the article, this is about your repeated attempts to violate policy. Glider87 (talk) 02:13, 28 June 2009 (UTC)

My thoughts

After reading the whole article i think someone with a technical knowledge in the subject should go thoroughly over the language to make sure it is more exact. As it stands now it seems to me its a bit superficial and in many cases the language used makes the point unclear. I.e the use of plate instead of platter, "laptop HDDs" insted of 2,5" HDD etc. It could also be a bit more organized. —Preceding unsigned comment added by 213.236.242.126 (talk) 02:02, 4 July 2009 (UTC)

Capacity and access speed

Under the "Capacity and access speed" section, the article reads,

"A typical "desktop HDD" might store between 120 GB and 2 TB although rarely above 500GB of data (based on US market data[17]) rotate at 5,400 to 10,000 rpm and have a media transfer rate of 1 Gbit/s or higher. Some newer have 3Gbit/s.[citation needed] (1 GB = 10⁹ B; 1 Gbit/s = 10⁹ bit/s)."

It then talks about enterprise hard drives:

"The fastest “enterprise” HDDs spin at 10,000 or 15,000 rpm, and can achieve sequential media transfer speeds above 1.6 Gbit/s.[18] and a sustained transfer rate up to 125 MBytes/second."

I would argue that the article incorrectly sites the media transfer rate for the desktop HDD and should instead refer to it as the drive interface rate (3Gbit/s is the maximum interface transfer rate of SerialATA 2nd generation. I know of no HDDs that can actually read/write that fast). If you agree with that statement then I would continue and argue that providing only the interface rates for desktop HDDs and only the media transfer speeds for enterprise hdds is confusing to the reader.

I can provide some links to average transfer speeds for both types of hdds if someone wishes to continue this discussion. —Preceding unsigned comment added by Axonjacksn (talk • contribs) 14:40, 6 July 2009 (UTC)

First image

It might be helpful to change the image to show an assembled 3.5" drive with a cover in place. Almost every picture on the page shows drives in various states of disassembly. A person might be misled into believing a drive naturally has the platters exposed. Alexdi (talk) 22:18, 7 August 2009 (UTC)

I agree. The infobox used apparently does not support more than one image and caption. Otherwise I would have added the image from later down the page that is an enclosed HDD, which is named, appropriately, File:hdd.jpg. — Becksguy (talk) 16:24, 29 August 2009 (UTC)

Durability of data on hard disk

How long I can assume that data is readable from hard drive if it is not used while storing? In other words how long data remains unchanged in magnetic hard disk plate in ideal environment? --Jouni Valkonen (talk) 02:16, 4 February 2010 (UTC)

There is no reason to expect the data to be gone although it might be difficult to access it. For example, an IBM RAMAC 350, last used in the 60s still has readable data today at the Computer History Museum! Most of the electrical and mechanical components had long since failed or disappeared so it took a restoration team to access the data, but it was there. I recently powered up an HDD last used circa 1995; it worked and I was able to retrieve data. If a drive hasn't been used for a long time, I'd worry about parts sticking together and preventing motion (either spindle turning or actuator moving heads or both). Rumors are that some folks have recovered stuck drives by freezing and thawing them. If its a real old drive, you might have trouble interfacing it to a system, but the data are likely there. Tom94022 (talk) 00:29, 23 March 2010 (UTC)

I agree that hard drives and magnetic media is the most time-tested and proven long-time storage technique. However, while the media will probably be fine in 50 years, I would be concerned about the mechanics getting stuck or lubrication drying up. I've heard that some national archives employ personnel whose only job is to spin up hard drives periodically to make sure they don't get stuck. But I can't find any sources to confirm this, so take of it what you will. -- intgr [talk] 15:38, 23 March 2010 (UTC)

"Analysis of data from an accelerated life test predicts that, if data is written to 160GB RDX removable hard drive cartridges based on 2.5 laptop disk technology, and the cartridges are then stored in realistic conditions for 30 years, more than 99% of the drives will then read their entire contents with no errors. ... To the best of our knowledge, this is the first published work on non-spinning media and thus complements these studies"^[1]

Such 2½-inch drives generally use ramp loaded heads which prevents heads sticking to a disk while not in use, but that doesn't prevent the head arm from binding to the plastic ramp, nor the cold welding or brinelling of motor bearings nor other mechanical or electrical aging problems. However, the results from such accelerated test are encouraging. Tom94022 (talk) 16:40, 23 March 2010 (UTC)

"RAID should never be relied on as a backup"

From [the article]:

"Eventually all mechanical hard disk drives fail. And thus the strategy to mitigate loss of data is to have redundancy in some form, like RAID and backup. RAID should never be relied on as backup, because a localized event such as a power-surge or a fire could destroy several drives at once. Following a backup strategy; for example, daily differential and weekly full backups, is the only sure way to prevent data loss."

This seems controversial, is it just an endorsement for offsite backup providers? --129.244.241.84 (talk) 18:26, 9 April 2010 (UTC)

No it is not. How does RAID protect you in the event of fire, theft, or plain old operator error? It doesn't. Mechanical breakdown is not the only reason to keep backups. CrispMuncher (talk) 02:10, 10 April 2010 (UTC)

Yes it is controversial. RAID protects you to a degree, that is, no single failure of the RAID protected components will cause loss of data. That may be sufficient for most people. A power surge is unlikely to cause any one drive failure much less multiple failures and with regards to fire, how many people make duplicate copies of their photos and store one copy off site? Personally I use a pair of local mirrored systems with a third local backup system - basically three copies and take my chances that a fire will take them all out. However, if you really value your data then an off site backup may not be enough, take a look at LOCKSS (Lots of Copies Keep Stuff Safe) for one end of the spectrum - a key aspect there is continuous checking that all the copies are correct. Tom94022 (talk) 03:47, 10 April 2010 (UTC)

Not controversial, in my opinion, but should be expressed in a more factual and less authoritarian manner. Just as RAID does not cover the situations listed, backup is not a 100% "sure way to prevent data loss" either, as the backups could be destroyed or rendered useless due to any number of causes. How about:

"RAID cannot be relied on as backup, because a localized event such as fire or theft could destroy all the drives at once. Following a backup strategy, such as daily differential and weekly full backups to an off-site location, offers better protection."

Or "RAID is vulnerable to a localized event such as fire or theft that could destroy all the drives at once."

Amniarix (talk) 12:17, 12 April 2010 (UTC). Updated article Amniarix (talk) 10:34, 16 April 2010 (UTC).

It may be useful to distinguish various types of backups. Raid does help prevent data loss from drive failure, but it is not in the strict sense a backup system. It does not providing version control (for example, if I run incremental backups to tape every day, I can get the version of last tuesday), and if the raid fails, data loss can occur (ask me how I know). --Nuujinn (talk) 00:05, 13 April 2010 (UTC)

"RAID is vulnerable to a localized event such as fire or theft that could loss of data." as a footnote makes sense to me; everything else, including the original sentance seems to be TMI and more appropriate to articles on RAID and Backup. Tom94022 (talk) 15:56, 16 April 2010 (UTC)

And areal densities are...?

How many bits per square centimeter are these devices storing? —Preceding unsigned comment added by 207.81.141.207 (talk) 22:37, 23 April 2010 (UTC)

image of magnetic domain structure

can someone add an image of the microscopic magnetic domain structure on the disk surface?

for example: http://www.azonano.com/images/Article_Images/ImageForArticle_2248(4).jpg from: http://www.azonano.com/details.asp?ArticleID=2248 —Preceding unsigned comment added by 109.186.154.174 (talk) 00:08, 14 May 2010 (UTC)

'Hard' why exactly?

This entire article does not at any point explain why HDDs are called called hard disk drives. H0dges (talk) 22:26, 22 January 2010 (UTC)

Now answered. Please do not put new sections at the top of a talk:article Tom94022 (talk) 22:53, 22 January 2010 (UTC)

Nope, new sections should be at the bottom, please read WP:TALK. -- intgr [talk] 15:08, 23 March 2010 (UTC)

The reason for "hard" is to contrast it to "floppy". This was done in seventies to reduce confusion between floppy drive and hard or "rigid media" drive when Shugard Associates started shipping the floppy drives. (I hope people still remember what a floppy dive is). (Astrin (talk) 20:40, 1 June 2010 (UTC))

Spliting Lagest capacity hdd table 2.5inch category in two

"Current hard disk form factors"

I would like to ask for spliting category of Largest drives capacity, 2.5inches drives into two heights category.

I do not know it exactly. But It should divide this according to height of slot for hdd in most of laptops, and other which gives largest capacity of 2.5inch hdd avaible. {There are times when it is the same amount of capacity.}

Since this table has 3 rows, it shoudn't be a problem to add one. —Preceding unsigned comment added by 95.108.17.230 (talk) 12:09, 21 May 2010 (UTC)

I would not recommend it; the maximum capacity in a form factor is almost always with the tallest drive. Also there are or have been several z heights within a form factor, so where do you stop? Tom94022 (talk) 07:18, 25 May 2010 (UTC)

Merge Enterprise disk drive

Enterprise disk drive contains a combination of duplicate and overlap material. For example, drive class is effectively covered by Capacity and Access Speed. Any overlap, such as a mention of increased reliability drives, should be integrated into this article, possibility into respective integrity and disk failure sections. Should this merge proceed? Mamyles (talk) 01:55, 24 April 2010 (UTC)

Yes Tom94022 (talk) 04:21, 24 April 2010 (UTC)

I agree.Galmicmi (talk) 19:07, 29 May 2010 (UTC)

Agreed. Music Sorter (talk) 04:40, 15 June 2010 (UTC)

Agree. Becksguy (talk) 08:55, 15 June 2010 (UTC)

Done, editorial improvement would be appreciated. Tom94022 (talk) 19:14, 15 June 2010 (UTC)

Intro Missing Binary vs SI Units Discussion

I am going to jump and and say it's fascinating for people to argue over the trivial and ignore the elephant in the room. You would think for the NPOV you could have at least have a mention of that whole GB/GiB 2+2=5 rewriting of history. A more disturbing clearly not NPOV or rewriting of history is:

Raw unformatted capacity of a hard disk drive is usually quoted with SI prefixes (metric system prefixes), incrementing by powers of 1000...

With no mention that apparently for pretty much all of the consumer PC era up to about 1994 or 1995, since after that...when the "1 GB" mark was "reached" by changing the definition...not only was it confusing and a major story, but actually for a time only drives above that "1 GB" threshold used the "SI" math that it took years for them to get groups like the IEEE and NIST to change the definition for them.

No standards body changed the definitions of the SI prefix; we misused them deliberately, and often grotesquely, e.g., "M"=1024000, "Octal K"=512, and newcomers were unaware that it was a misuse. What the IEC did was to introduce a new series of prefixes. Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:19, 18 June 2010 (UTC)

Excluding this part of history and more importantly the huge impact and ripple effect it has had in general on the concept of specs and standards is to not give credit or blame where it is due. Strangely (or no surprise) almost all the timelines of storage history skip over that "1 GB" mark for 3.5 inch hard disks which turned out to be the most important storage or capacity threshold in history and the first and only one I know of where a single sector's or company's marketing scheme retroactively became a standard in time. This is not like rewriting even the 1950s. If the car or airline industries are stuck with their historic mistakes or legal or marketing missteps...why should another get off so easily when it is well within recent memory.

There must be a single person in the industry or otherwise to put in a proper reference. I think I recycled all my hard copies of Byte making fun of the first past that goal line...after moving the line. This almost makes many historic war revisionist history seem pale by comparison. The public evidence in all the lawsuits related are likely available too and will not be scrubbed so easily.

Can I really be the only person this bothers? I know they already won and we have our new "GB" and "MB" now, but I would like to keep my reality based memory and history and give these influential companies full credit/blame for a monumental shift in computing history....pretty much the day the marketing departments got the engineers to surrender.

Thehighlndr (talk) 21:44, 5 June 2010 (UTC)

I moved this material into a new section because it is really a separate discussion. I agree your sentence about this issue is worthy of the introduction and will shortly move it there. The topic is treated in detail within the article at Hard disk drive#Capacity measurements. Your participation in the Binary Prefix war next time it starts would also be appreciated. Tom94022 (talk) 22:59, 5 June 2010 (UTC)

Air Bearing Question

Copied the following from above section to separate two discussions

Similarly, while modern disk drives exploit the Bernoulli effect, older drives had a larger air gap and relied on the mechanics of the arm for correct positioning. Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:08, 18 June 2010 (UTC)

I'm not sure I understand or agree with yr Bernoulli comment - the word does not appear in the article. The first disk drives had hydrostatic air bearings, but they were then quickly replaced with hydrodynamic air bearings which lasted until today (if you accept today's negative pressure air bearings are still hydrodynamic), all of which are accurately summarized by the exiting text in the article. I suppose detail as to how heads fly or how air bearings are and were created might be added in a new section, but as it stands I don't see any changes necessary on the flying head material in the current article. Tom94022 (talk) 18:17, 18 June 2010 (UTC)

The phrase Bernoulli effect does not appear in the article, but the text float on a cushion of air above the platters describes an application of it. My recollection is that the use of small air gaps started in the late 1970's with the IBM 3350. Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:06, 18 June 2010 (UTC)

I think we started with RAMAC at about 100 uinch and as I recall the 3330-11 was about 40 uinch and the 3350 was in the range of 12 uinch - it looks like a pretty continuous descent to me. Some might argue there was a change in 1973 with the 3340 from high mass high load slider to low mass low load sliders and then in 1990 with the IBM Sawmill from positive pressure air bearings to negative pressure air bearings, but that would be TMI. Tom94022 (talk) 00:28, 19 June 2010 (UTC)

Intro NPOV

I don't have much time to elaborate but the second paragraph of Alexdi's edit regarding flash is not supported by any industry analyst while his first paragraph about performance is TMI at this point in the article. I will elaborate more later, but my recommendation is both paragraphs be deleted. Here they are

Performance Paragraph [added for clarity Tom94022 (talk) 20:55, 28 May 2010 (UTC)]

Despite their utility, hard disk design introduces inherent performance compromises. The manipulation of sequential data depends upon the rotational speed of the platters and the data recording density. Because heat and vibration limit rotational speed, advancing density becomes the sole method to improve sequential transfer rates. While these advances exponentially increase storage capacity, the performance gains they enable are only linear. Performance relative to capacity in new generations of hard disks has therefore fallen with time. Operations on non-sequential data are further compromised by the overhead of moving the read/write heads to new positions. The more scattered the data, the more transfer rates suffer. The multi-layer caching structure of modern computers is a direct response to these limitations.

Uncertain Paragraph [added for clarity Tom94022 (talk) 20:55, 28 May 2010 (UTC)]

As of 2010, the arrival of inexpensive non-volatile flash memory has made the continued dominance of hard disks in personal computing uncertain. Storage capacity has increased at a rate far in excess of the data requirements of common productivity applications. Media-streaming from distant servers continues to rise in popularity,[5] concurrent with the appearance of portable devices that call for a level of power consumption, durability, and instant-access that a hard disk cannot provide. While the aggregate data demands of all users will continue to expand, future hard disk market share may shift to the enterprise sector.

Tom94022 (talk) 07:14, 25 May 2010 (UTC)

Naturally, I disagree. I rewrote the introduction because it didn't have any context. To a person unfamiliar to hard disks, the article appears to be a mass of technical information with very little perspective. Because the performance characteristics of hard disks are inherent to the design and so fundamental to understanding why they're used the way they are, I think they merit inclusion in the introduction.

That said, the second paragraph (about flash) is factual. The neutrality tag could apply to the third paragraph, but these trends are sufficiently established allow inclusion in this article. Only the last sentence is debatable. It's inevitable that solid-state memory will overtake mechanical storage. Whether enterprise will be the last bastion for hard disks is less certain.

Here's an outside reference: http://www.tomshardware.com/reviews/hitachi-interview-hdd-ssd,2586-2.html

The last two questions are on point. The first touches on the erosion of hard disk use in portable devices. Alexdi (talk) 20:49, 25 May 2010 (UTC)

Of course u disagree, but u should not remove the tag until we have had a chance to discuss it amongst ourselves and with other editors. I also believe the first paragraph is not NPOV since it is all about alleged performance issues with HDDs. A neutral paragraph would talk about both the advantages and limitations. Tom94022 (talk) 06:17, 26 May 2010 (UTC)

Comments on Uncertain Paragraph

[added subsection to allow for clarity of discussion]Tom94022 (talk) 20:55, 28 May 2010 (UTC)

Flash has nothing to do with introducing HDDs. It does belong in this article, but in it's own section. All the intro needs is a statement about the future of HDDs being uncertain due to the introduction of flash with various benefits.71.4.236.2 (talk) 17:04, 26 May 2010 (UTC)

I agree that Flash has does not belong in the introductory paragraph. No serious observer of the HDD market suggests that there is any uncertainty about the continuous dominance of HDDs for the foreseeable future; the debate is mainly about what small market share the SSDs will obtain by 2015. I will have some cites later, but in the meantime is seems to me speculation about alleged HDD uncertainty violates Wikipedia is not a crystal_ball! Tom94022 (talk) 00:00, 27 May 2010 (UTC)

I'm amenable to revising the first and last line of the third paragraph to present a softer and less committal view of the trends I listed. Or if you don't think they're representative of the market at large, the paragraph could be shifted to a new section on market growth and positioning. As to the earlier paragraph, there are no 'alleged performance issues' in the new content. All of the relationships I mentioned are fundamental to the architecture. Whether they're an issue is a matter of perspective; to those building portable devices, many of them are. Alexdi (talk) 04:44, 27 May 2010 (UTC)

I fully believe that HDDs will soon be replaced by SSDs. But that has nothing to do with the definition of HDD, and is just opinion anyway. Of course the paragraphs should be deleted from the intro. --A D Monroe III (talk) 12:25, 27 May 2010 (UTC)

The lead section is not just a definition. Per Wikipedia's guidelines, "The lead should be able to stand alone as a concise overview of the article. It should define the topic, establish context, explain why the subject is interesting or notable, and summarize the most important points—including any notable controversies." I rewrote it with these goals in mind. Insofar as an issue cannot be reduced to facts (as would be the case when gauging the significance of anything), opinion is not excluded from Wikipedia. Alexdi (talk) 21:29, 27 May 2010 (UTC)

They way the paragraph is presented it sounds as though HDDs are a dying technology.

"As of 2010, the arrival of inexpensive non-volatile flash memory has made the continued dominance of hard disks in personal computing uncertain." 100% opinion, everything from non-volatile flash memory being inexpensive, as something thats inexpensive to someone might not be to another, to HDDs future in personal computing. Should be re-written to say that the costs of producing non-voliate flash memory are contining to drop and may soon be on par with HDDs. No mention to HDDs future should be made.

Would this sentence work if the section about 'continued dominance' was sourced? Alexdi (talk) 03:38, 29 May 2010 (UTC)

"Storage capacity has increased at a rate far in excess of the data requirements of common productivity applications." Is this sentence detailing how the capacity of SSDs have increased or HDDs, no distiction is made and may confuse the reader. Currently, I can purchased a fairly large HDD (>=2TB) for considerably less than a SSD with a storage capacity only a fraction of what the HDD has.

I agree that it should read "Hard disk storage capacity". Alexdi (talk) 03:38, 29 May 2010 (UTC)

"Media-streaming from distant servers continues to rise in popularity,[5] concurrent with the appearance of portable devices that call for a level of power consumption, durability, and instant-access that a hard disk cannot provide." I fail to see how this sentence is relevant. Media-streaming has more to do with the internet than HDDs as there is generally no way to tell whether the server is using HDDs or SSDs. HDDs and SSDs power consumption is similar according to Tom's Hardware (http://www.tomshardware.com/reviews/ssd-hard-drive,1968.html). I agree with the durability of HDDs vs. SSDs, however, the instant-access of each storage device is dependant on the interface, whether its in a lower power state or not as well as condition, generally HDD dependant though. The access times are on the order of milliseconds and only enthusiasts would really be able to tell much of a difference.

The gist of the first part of that sentence is that local storage isn't as important as it once was. The primary driver of the storage market is media: movies, music, and recorded television. While a few people may keep movies and the like on a personal server, the rest rely on Netflix, Pandora, and other streaming services that require very little local storage.

The second part of the sentence is an overview of solid-state characteristics that benefit portable devices. Any counterpoint is quibbling; almost every small portable device (e.g., iPads, smartphones, music players) uses solid-state storage for those reasons, and for at least five years, the market share of non-mobile computers has fallen relative to portables. Alexdi (talk) 03:38, 29 May 2010 (UTC)

"While the aggregate data demands of all users will continue to expand, future hard disk market share may shift to the enterprise sector." Again, no distinction between HDD and SSD as *hard drive* is a technical term shared by both. Should be re-written with less opinion and designations made between HDDs and SSDs. Ulrichcp (talk) 16:49, 28 May 2010 (UTC)

Does there appear to be consensus that the "Uncertain" paragraph should be stricken? Tom94022 (talk) 20:56, 28 May 2010 (UTC)

Per Wikipedia guidelines, the focus should be on revision, not deletion. Given that hard disks are the dominant storage mechanism, an overview of storage trends should be in the introduction. Alexdi (talk) 03:38, 29 May 2010 (UTC)

This is an HDD article not a storage article. Perhaps something along the lines is at most appropriate in the introduction:

Hard disk drives have been dominant device for secondary storage of data in computer systems since the early 1960s. They have maintained this position because advances in their areal recording density have kept pace with the requirements for secondary storage. Over this fifty year history there have been many proposed “gap-filler” technologies which have failed to provide superior cost and performance requirements than HDDs have provided for such storage.

You are still the only editor advocating the "uncertain" theme of this paragraph. There is nothing in the Wiki guidelines that says POV and TMI should not be deleted. Tom94022 (talk) 05:19, 29 May 2010 (UTC)

I disagree with your characterization. Context isn't TMI; the intro should contain a paragraph of where the hard disk was, is, and perhaps even will be. By contrast, the mechanical details in the quote you provided are vastly more appropriate for the body of the article. Those details just clutter the introduction, and they're awful writing besides. As to POV, that's a matter of phrasing. The trends themselves have no POV. Alexdi (talk) 20:18, 29 May 2010 (UTC)

To insist on the significance of the small current trend into the future is POV. HDDs have been "doomed" many times before, by bubble memory, optical, even improvments in tape, and yet HDDs are still here. A single line about tape, floppies, and SDDs as alternatives is all that's warrented. I think the paragraph is so contrived it should be deleted, but I'd be okay if it were just moved out of the intro. --A D Monroe III (talk) 17:11, 30 May 2010 (UTC)

PROPOSED REPLACEMENT FOR THE ENTIRE UNCERTAIN PARAGARPH

HDDs have been dominant device for secondary storage of data in computers since the early 1960s. They have maintained this position because advances in their areal recording density have kept pace with the requirements for secondary storage. Over this fifty year history there have been many proposed replacement technologies which have failed to provide superior cost and performance requirements than HDDs have provided for such storage. Flash Memory in forms such as Solid state drives is the latest contender to replace HDDs; however most analysts doubt that such a replacement is likely in the foreseeable future.

I will find a suitable reference for the last sentence - The first two sentences come from Mee & Daniel. There probably should be a footnote that Flash dominates hand held computing devices, a market segment in which HDDs have had little success. Again this is an introductory paragraph in which only top level material should be present. Comments? Tom94022 (talk) 17:33, 30 May 2010 (UTC)

The first sentence duplicates the second paragraph of the article.

I agree that the idea should be incorporated into the second paragraph but it is not duplicative. Tom94022 (talk) 18:04, 7 June 2010 (UTC)

The second sentence is incomplete and not necessarily accurate. Some would say that storage capacity drives storage utilization, or that the two are symbiotic. The real reason hard disks dominate is that all other technologies have had flaws fatal to mainstream adoption. Other forms of long-term storage have all been one of two types: magnetic and mechanical (tapes, floppies), or optical and mechanical (CDs, DVDs). Both were either displaced by hard disks or never intended to be primary storage. We haven't had any attempts at the use of non-volatile memory for mass storage in the last thirty years. Flash memory is a paradigm shift with little historical precedent.

The second sentence comes from a reliable source; SSDs have the same fatal flaw. Their is no evidence that Flash memory is any more of a paradigm shift than bubble memory. Tom94022 (talk) 18:04, 7 June 2010 (UTC)

The third sentence would have to read something like, "... failed to provide a balance of cost and performance capable of of displacing hard disks in the mainstream."

good idea but I would add the idea of mainsteam secondary storage. Tom94022 (talk) 18:04, 7 June 2010 (UTC)

The latter half of the fourth sentence is mealy-mouthed and probably not accurate. You can't say "most analysts" unless you've taken or found a recent sampling of most analysts. Nevermind most, I doubt you could even find one to agree that hard disks won't be replaced in significant market segments in the foreseeable future. The near-future of the next few years, perhaps, but "foreseeable" extends quite a lot further.

I wanted to say "all mainstream analysts" but I figured someone would find some analyst to say otherwise. Tom94022 (talk) 18:04, 7 June 2010 (UTC)

HDD and SSD cost-per-gigabyte have accelerated at near the same rate for years. If this trend continues, we can expect SSDs to stay more expensive at any particular capacity. But since capacity requirements for mainstream users rise at a much slower rate, we can also expect that small-capacity drives (relative to the largest available capacities) will eventually become acceptable for most users. Since the cost advantage of hard disks at these sizes will be minimal or even inverted (hard disks have a higher base materials cost), SSDs will eventually displace hard disks. The question isn't if, it's when, and since it's already happening with high-end laptops, I don't think it's reasonable to say 'hard disks will be dominant in the foreseeable future'.

I actually agree that there is chance that SSDs might replace HDDs in laptop computers and even desktop computers since there maybe a capacity above which there is no value in these applications, much like there was not much value above 4 GB in MP3 players. BUT that is POV and OR of the first order and so far there has been no reliable source to say so. Therefore it is not appropriate for the introduction to the article.

That said, I don't think hard disks are dying. There will always be a place for the highest capacity at the lowest price, and long-term storage benefits less from SSD advantages. If my original phrasing seems to suggest that death is imminent, it should be softened.

Alexdi (talk) 22:30, 1 June 2010 (UTC)

Please read Flash Cache is Back for one of the latest views on why SSDs haven't and will not replace HDDs. Tom94022 (talk) 18:04, 7 June 2010 (UTC)

At this point there has not been a single editor that supports the "Uncertain" paragraph (including Johnuniq (talk) in Performance paragraph) - can we delete it now? Tom94022 (talk) 18:04, 7 June 2010 (UTC)

Please. Stericulous (talk) 04:19, 8 June 2010 (UTC)

Comments on Performance Paragraph

As I stated above this paragraph is all about alleged performance issues with HDDs whereas a neutral paragraph would talk about both the advantages and limitations. HDDs have dominated the secondary storage portion of the storage heirarchy since the 1960s and all observers believe they will continue to do so for the foreseeable future. In an introduction to HDDs I would think the article would point to the [Data Storage] article and explain how a disk drive works and thereby achieves a balance in cost and performance between memory on one hand and secondary storage such as tape on the other hand. The introduction should be based upon a reliable source and not some ad hoc WP:OR by an editor. By reliable source, for example, I mean this paraphrase:

Hard disk drives consist of a single disk, or stack of disks, which have a thin magnetic coating and rotate at a high speed. The disk surfaces are recorded using heads mounted on arms that are moved across the disk surfaces by a high-speed actuator. User data are recorded in sectors of circumferential tracks on the disk surfaces. Position information (called servo data) is embedded in the tracks as prerecorded sectors. Digital recording is used and information is read back as strings of encoded positive and negative voltage pulses that are detected in a recording channel. The mechanical and electronic systems of a hard disk drive usually consist of a head-disk assembly; the data channel, which processes the analog read signals and digital write-current pulses; and the actuator control system, which controls the position of the actuator and the head-arm assembly over the disk surfaces.

Tom94022 (talk) 20:55, 28 May 2010 (UTC)

Alexdi now proposes the following paragraph about performance:

The mechanical nature of hard disks introduces certain performance compromises. The manipulation of sequential data depends upon the rotational speed of the platters and the data recording density. Because heat and vibration limit rotational speed, advancing density becomes the sole method to improve sequential transfer rates. While these advances exponentially increase storage capacity, the performance gains they enable are linear. Performance relative to capacity in new generations of hard disks has therefore fallen with time. Operations on non-sequential data are further compromised by the overhead of moving the read/write heads to new positions. The more scattered the data, the more transfer rates decline. The multi-layer caching structure of modern computers is a response to these attributes.

There are a multitude of technologies that have contributed to the increased capacity and performance of hard disk drives. Of the many, rotational speed is relatively unimportant and therefore is TMI for the introductory section of this article. Furthermore there evidence is that both speeds and data rate can and will be increased as the market demands - if nothing else we can always go to parallel head transfer. There is no evidence that performance relative to capacity is a meaningful metric. There is no evidence that the caching structure has anything to do with disks, in fact, it has much more to do with memory bus bandwidth. This whole paragraph is POV and/or bad OR and should be stricken. A few sentences about the progression in areal density, its likely continuation and something placing its performance in the memory heirarchy is all that should be in an introductory paragraph. Tom94022 (talk) 23:31, 5 June 2010 (UTC)

The disputed section absolutely has to go. Its inclusion in the introduction would be akin to having a paragraph about the theoretical limitations of copper in the opening of the article about Cat5e. Make a section called limiting factors or something similar and stick it there, but please take it out of the opening. It sounds like a sales pitch from someone who sells flash memory, solid state drives, or off-site storage and is planning on sending prospective clients to Wikipedia to back up their hard sell. Stericulous (talk) 07:09, 7 June 2010 (UTC)

The comparison to CAT-5 is inapt. The performance paragraph is specific to hard disks, not a component or substrate. It's a generalization, not a theory. As above, however, I'm not adverse to moving it elsewhere.Alexdi (talk) 22:51, 11 June 2010 (UTC)

This article is not the place to decide which is the superior technology, and it is absurd to have an editorial on the merits of flash memory in the lead of an article on hard disks. Articles should not speculate about the future, apart from reporting important developments supported by reliable sources (and predicting the future requires a really reliable source). It would be reasonable for this article to have a small section referring to the fact that some current systems use alternatives (flash memory and what have you), for some good reasons (briefly list them). There is no reason to refer to alternatives in the lead. Johnuniq (talk) 08:29, 7 June 2010 (UTC)

Wikipedia's lead guidelines differ with your opinion. The lead should summarize and abstract major points from the article. Given that flash are hard disks are the only two competitors of any significance for long-term storage, it's not out of order to expect a mention. I think I've been overruled on this point, however. Alexdi (talk) 22:51, 11 June 2010 (UTC)

But there is no section in the article on the future of flash, so there should not be such a section in the lead (which is a summary of the article). Of course flash will continue to improve and replace disks in small/portable/military systems, and that could be briefly mentioned, with sources and a link to a main article. OTOH people have been predicting the death of hard disks for some years ("death" in the sense of reaching the limits of technology, so not economically improvable). Johnuniq (talk) 00:57, 12 June 2010 (UTC)

I think I am in the most recent string of comments on the topic of Flash memory and any relevance to the HDD article. I have not been monitoring the discussion until today, so I hope I have followed the above (messy) thread on the topic. I agree with Johnuniq that there is no section in the article on flash and that is something we should address. I would recommend something at the end possibly titled "Alternative secondary storage" or maybe just get to the point and call it "Solid state drives impact on HDDs". We could start with a {main|Solid state drive} entry and then point out the numerous sources that talk about how little an impact the SSD has had on total HDD volume and cover the different viewpoints on the controversy. We could cover the basic differences between HDDs and SSDs without getting into the significant details. I think anyone looking at the HDD article would expect to see something on the technology that at least claims to be on the forefront of taking part of its marketshare. § Music Sorter § (talk) 06:03, 23 June 2010 (UTC)

Revisions for consideration, 6/1

The mechanical nature of hard disks introduces certain performance compromises. The manipulation of sequential data depends upon the rotational speed of the platters and the data recording density. Because heat and vibration limit rotational speed, advancing density becomes the sole method to improve sequential transfer rates. While these advances exponentially increase storage capacity, the performance gains they enable are linear. Performance relative to capacity in new generations of hard disks has therefore fallen with time. Operations on non-sequential data are further compromised by the overhead of moving the read/write heads to new positions. The more scattered the data, the more transfer rates decline. The multi-layer caching structure of modern computers is a response to these attributes.
Alternatives to hard disks for large-scale non-volatile storage are few. Only solid-state disks based on flash memory have made significant headway, aided by the popularity of portable devices that call for a level of power consumption, durability, and instant-access that hard disks cannot provide. These benefits come at a comparatively high cost-per-gigabyte, a factor that has slowed mainstream adoption. As of 2010, hard disks maintain the dominant market position.

In the first paragraph, I've removed or modified most words that could be considered inflammatory. The second paragraph is new, though it incorporates part of a sentence of the original. I've removed two trends that, while interesting, may not be sufficiently universal to draw conclusions, as well as the speculation of the last line. Alexdi (talk) 23:29, 1 June 2010 (UTC)

Since the discussions of the two paragraphs (Performance and Uncertain) you are proposing are likely to be different, I suggest you keep your comments and proposals within in the two sub-paragraphs above. IMO, your two proposed paragraphs in the quote box immediately above continue to be POV and/or TMI and I will respond above later in Comments on Uncertain Paragraph or Comments on Performance Paragraph as appropriate. Tom94022 (talk) 15:45, 2 June 2010 (UTC)

I think my revisions are reasonable. I would consider a conclusion from a 20-year-old text in this field to be vastly more POV. Other portions of this article are in such need of rewriting that your time would be better-spent letting this area lie. Alexdi (talk) 18:41, 2 June 2010 (UTC)

Hard drive 2.5 750 GB

It should be noted that Western Digital has made a 2.5 750 GB hard drive with a height of 9.5mm (Example, 2 platters) Change it. 209.188.63.194 (talk) 19:32, 11 June 2010 (UTC)

Well that sounded pretty demanding from someone without a login name and considering we are all volunteers. I made a few changes in that section including locating a more current citation from the same authors and publication. I also added citations for other parts of this section still needing a general improvement to meet Wikipedia standards.

I would love to see this page move to GA or even FA status. With all the editors we have watching this page maybe we can focus on the bigger picture to get it there and not worry so much about the nits. Of course that is just my opinion. :) § Music Sorter § (talk) 08:15, 23 June 2010 (UTC)

Data as singlar or plural

Yes, to be precise, "data" is plural, and "datum" is singular. But it makes no sense to edit war (as in: [6], [7], [8]) over the grammatical number of "data", when usage differs—or is ignored by—readers, writers, publications, dictionaries, and style guides. See Data in Wikipedia, data in Wiktionary, and data in Merriam-Webster for discussions of linguistic, grammatical, scientific, and daily usage. — Becksguy (talk) 15:29, 7 October 2009 (UTC)

It is more than precise, "are" is grammatically correct. Let's give 86.136.211.188 the benefit of doubt, perhaps he is not a native English speaker. But what excuse does Glider87 have, particularly since I explained the revision and he reverted without comment. Why don't u revert Glider87's revision and see who is edit warring? Tom94022 (talk) 21:37, 7 October 2009 (UTC)

Tom94022, don't try to insinuate others are edit warring when they are not. The change by 86.136.211.188 reads better than your revert, so you were reverted. I suggest you disengage to cool off. Glider87 (talk) 07:06, 8 October 2009 (UTC)

Exactly my point, the platters are spinning way to fast and needs to be slowed down. South Bay (talk) 07:10, 8 October 2009 (UTC)

"In formal or scientific writing, this word is usually a plural noun, with singular datum" [several sources]

It is impolite at the least and arguably the beginning of an edit war to, as Glider87 did, revert without explanation.

Glider87s belated explanation "reads better" is not an reasonable excuse for incorrect grammar.

Creating a strawman argument of an edit war is not a good reason for incorrect grammar.

If this is an edit war, then the article should be returned to its original "data are" construction until the war is ended.

I'd like to hear why Becksguy and South Bay won't end this purported edit war by supporting the grammatically correct construction.

Tom94022 (talk) 21:59, 10 October 2009 (UTC)

Perhaps the actuator arms have become malfunctioned and as a result the computer wont recognize the hard drive.South Bay (talk) 23:37, 10 October 2009 (UTC)

Tom stop trying to push the blame onto others. Leave it alone and do something else more productive. Glider87 (talk) 09:44, 12 October 2009 (UTC)

By my count there were 3 instances of "data are" in the article in addition to the one instance of "data is" that Music Sorter corrected and Alexdi reverted; so I reverted back. We ought to be consistent and I prefer the grammatically correct version. Tom94022 (talk) 17:14, 21 June 2010 (UTC)

All three should be changed. Data is a mass or collective noun. Collective nouns are singular. See here for discussion: http://www.textinenglish.com/?p=435. The conception of 'data' is of a singular set, not of individual pieces. See here for more discussion: http://grammar.ccc.commnet.edu/grammar/plurals.htm. The existing phrasing is awkward, pedantic, and should be put to consensus voting. Your preference is not controlling. Alexdi (talk) 21:08, 21 June 2010 (UTC)

Likewise your preference should not be controlling. I happen to find "data are" grammatically correct and neither awkward nor pedantic. At this point there does not appear to be any consensus and according to policy we should revert to the usage in all four places. So please revert until a consensus is arrived at. Tom94022 (talk) 22:41, 21 June 2010 (UTC)

You might also want to look at Data and if you really think "data are" to be pedantic and awkward have at it there also. 22:51, 21 June 2010 (UTC)

I'm with you. What I find awkward is piece of data in place of datum, which is the wording you wind up with if you insist on treating a plural as if it were a singular. Shmuel (Seymour J.) Metz Username:Chatul (talk) 23:25, 21 June 2010 (UTC)

I don't think that wording naturally follows. As I see it, 'data' is akin to saying 'a set of datums,' just as 'information' in the example Music Sorter gives below is a set of knowledge. The composition of a set may be plural, but the set itself is singular. Alexdi (talk) 03:05, 22 June 2010 (UTC)

I apologize for the lengthy reply, but I thought I would put all my thoughts together in one place. I certainly have an opinion on this topic, but I did want to clarify that I had not made any changes to “data is” or “data are” on this article. I believe they way Wikipedia tracks changes, if you make a change to a page it will assume you are making a change to something written by the last person to edit the article. I had made an insignificant change to the XML in the company infobox, but Wikipedia assumed the subsequent “data is” change was modifying my work (which it was not, unless I forgot another edit I did).

I often look to relevant style and grammar guides when trying to determine for myself whether I am right or wrong on a point of the English language (yes I am a native English speaker). In addition to that I also look at common usage where it makes sense.

I don’t think we are arguing that the original definition of Data (plural) and Datum (singular) are unclear. I think the question is whether society has now changed the meaning of the words. I think we all know this happens over time. Check out this from AskOxford.com:

http://www.askoxford.com/asktheexperts/faq/aboutgrammar/data

“Strictly speaking, data is the plural of datum, and should be used with a plural verb (like facts). However, there has been a growing tendency to use it as an equivalent to the uncountable noun information, followed by a singular verb. This is now regarded as generally acceptable in American use, and in the context of information technology. The traditional usage is still preferable, at least in Britain, but it may soon become a lost cause. Compare with agenda.”

Note the comparison with “agenda” which was in a similar situation and has since mutated like we are seeing for “data.”

Then I found this article and realized there was more to the definition than we all may be considering. I did not realize that Alexdi had already noted the mass noun definition for which I had not previously considered for this debate.

http://www.merriam-webster.com/dictionary/data

“Data leads a life of its own quite independent of datum, of which it was originally the plural. It occurs in two constructions: as a plural noun (like earnings), taking a plural verb and plural modifiers (as these, many, a few) but not cardinal numbers, and serving as a referent for plural pronouns; and as an abstract mass noun (like information), taking a singular verb and singular modifiers (as this, much, little), and being referred to by a singular pronoun. Both constructions are standard. The plural construction is more common in print, perhaps because the house style of some publishers mandates it.”

Here was the clincher for me when I considered other similar words (mass nouns):

Water, wheat, and information (mass nouns) are similar examples to the use of data in question. You can have “4 cups of water”, “5 pounds of wheat”, “9 pages of information”, and “500 bytes of data”. Water, wheat, and information are not plural in this case, but really mass nouns as is data in this usage. You can say “water is wet”, “wheat is grown”, “information is vital” and “data is saved” because they are all mass nouns.

I would vote that because data is both a mass noun and a plural noun that both are possible as long as the sentence structure would support the intended definition. I would further propose that if you can substitute the word "information" in place of the word "data" and the sentence is grammatically correct that it should stand as written under the definition for a mass noun.

I would vote that the 4 entries in this article can be defined as being used as mass nouns and can stand as written (also because the word "information" can easily be substituted for "data".

Data is encoded magnetically...

...onto which the data is recorded.

In this case the binary data is encoded...

...where no data is stored.

§ Music Sorter § (talk) 00:43, 22 June 2010 (UTC)

Yes please: "data is" is correct in these four instances, not from an examination of word origins, but from common usage (see "data is encoded" -wikipedia). Is there evidence of a contrary common usage in some places? Johnuniq (talk) 04:35, 22 June 2010 (UTC)

OK, I now understand that "data is" is acceptable in American English but that doesn't make "data are" unacceptable! Personally I don't use "data is." Wikipedia has 4,035 hits for "data is" and 2,224 hits for "data are". The Data article has in its first paragraph, "Data (plural of "datum", which is seldom used) are typically..." [emphasis added] but then uses both forms in the article explaining the various useages. So in the absence of a WP:MOS guide, shouldn't we respect the choice of the original author(s) and only impose a change in an article for consistency? If so, the article should be reverted to "data are." Tom94022 (talk) 14:08, 22 June 2010 (UTC)

If you are going to use the "respect the original" argument you need to go back to the original. The first entry in the history (looks like the 25 February 2002 version) use it as singular - the earlier dated one appears to be later in reality but also treats it as singular. So what "original author" are you referring to? My view is that in a computer context "25 data" is meaningless making the mass noun argument compelling. In any case do we really need to go all around this argument again? Crispmuncher (talk) 15:51, 22 June 2010 (UTC)

Nice strawman argument, I was referring to the original authors of the text in question, and not necessarily the original editor of the article. And in this case, I believe all four usages began as "data are", but clearly on Jun 21 three of the four usages were "data are." The one case I think was the previous go around. If the language police would leave the acceptable "data are" usages alone we could be done with this but I don't think they will. Tom94022 (talk) 01:23, 24 June 2010 (UTC)

No. You accept that the original text used data as a mass noun. If consistency is the goal then any subsequent edits should respect that usage. If subsequents edits introduce the plural sense it it they that are in error and therefore they that should be edited to ensure consistency: it is those edits that break the the MOS guidance. It is inappropriate to accept changes that alter the balance away from the original sense and then cite those as evidence of what the original usage was. That is not a straw man argument: attempting to casually dismissing it as such is nonsense. Exactly how did I misrepresent you? It is an argument for using the principle of consistency that you yourself advanced in a consistent manner. Crispmuncher (talk) 18:53, 24 June 2010 (UTC)

I suggested a Google search above ("data is encoded" -wikipedia). Here is another "data is encoded" site:.co.uk. These verify that "data is" is very commonly used in technical documentation in more than the U.S. Data#Usage in English shows widely differing views, but it claims "British usage now widely accepts treating data as singular in standard English", and Data (computing) (while very short) supports "data is". Johnuniq (talk) 01:54, 23 June 2010 (UTC)

The suggested Google search above will show approximately equivalent usages of "data is" and "data are" with many of the early hits explaining just that. I really don't think it is necessary to go back to the original, but if you do you will find that the "data is" usage was dropped after a few edits and I think "data are" adopted soon after. Sometime later it got mixed. What you should consider is that the on Jun 21 three of the four usages in the article were "data are" and Music Sorter (or someone) then made the article consistent by changed the one instance of "data is". In the absence of a WP:MOS that should have been the end of it. Alexdi's subsequent multiple reversions served no useful purpose other than enforce his view of the usage. Tom94022 (talk) 03:06, 23 June 2010 (UTC)

Dispute generality of claims

The article fails to distinguish between traits that apply to all disk drives and traits that apply only to some. In particular, not only is it incorrect that disk drives have an arm per platter, but the article cites drives that do not. The IBM 350, IBM 353 and IBM 355 all had arms that moved both vertically and horizontally. I'm not aware of any disk drive prior to the IBM 1301 that had an arm per platter.

Similarly, while modern disk drives exploit the Bernoulli effect, older drives had a larger air gap and relied on the mechanics of the arm for correct positioning. Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:08, 18 June 2010 (UTC)

I suspect the historically curious mechanisms belong in the History of HDDs article, if at all, and to be so specific in this article would be TMI. Perhaps this article could be qualified by the use of modifiers such as "today," "typically," etc. to make it accurate and thereby avoid TMI.

I'm inclined to go with adding, e.g., "contemporary", to the text, but I'm too new to Wiki to have an opinion on what constitutes TMI. Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:06, 18 June 2010 (UTC)

I added "In modern drives" which is used elsewhere in the article as a qualifier and therefore removed the dispute tag. Tom94022 (talk) 00:28, 19 June 2010 (UTC)

I caught a few more. I've also added a paragraph on disks that were not formatted into sectors. If you consider it appropriate I'll add some references, although I don't have anything going back before the 1301. Shmuel (Seymour J.) Metz Username:Chatul (talk) 01:54, 20 June 2010 (UTC)

I removed the added "modern drive" qualifications because they are not true. All HDD heads since the beginning have flown on a very thin cushion of air; it has gotten thinner and the way it has been generated has changed, but it remains a very thin cushion of air, aka air bearing.

Timeline: 50 Years of Hard Drives gives a date of 1961 for the air bearing. Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:46, 20 June 2010 (UTC)

The article is incorrect, the 1301 in 1961 was the first usage of hydrodynamic air bearings; the previous disk drives used hydrostatic air bearings, just do this Google search "RAMAC air bearing.Tom94022 (talk) 23:27, 20 June 2010 (UTC)

I am not sure that the RAMAC "read a track at a time" - can you provide a cite? I suspect it was fixed block addressable to the sector and the 1301 probably did introduce variable block with keys (aka CKD) but isn't this TMI for this article - why not put it into History of hard disk drives?

Tom94022 (talk) 19:14, 20 June 2010 (UTC)

I've programmed for the 355; it had 60 signed ten digit words per track and no sectors. I have no information on the 350 or 353.

This is what IBM says about the RAMAC 350

IBM 350 disk storage unit

It was configured with 50 magnetic disks containing 50,000 sectors, each of which held 100 alphanumeric characters, for a capacity of 5 million characters. (emphasis added)

IBM Archives

Tom94022 (talk) 23:27, 20 June 2010 (UTC)

The 1301 did not have CKD; it used a different flavor of self-formating track.

My concern wasn't completeness, but accuracy. Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:46, 20 June 2010 (UTC)

I too am concerned with accuracy; the phrase u use, "self-formating" track is not a term of the art; fixed block size (sector) or variable block size (ckd) are more common. Do you have a cite for either the 350 or the 355 that supports the full track read statement? Tom94022 (talk) 23:27, 20 June 2010 (UTC)

IBM 650 RAMAC® Manual of Operation Preliminary Edition, p. 18, 22-6270-3 (June 1, 1957)

86 RDS (Read-Disk Storage)

The purpose of this instruction is to read the entire track of 600 digits of data and place them in immediate-access storage.

As for the 1301, it was neither sector oriented nor CKD; there was a format track on each cylinder and an order called Set Format to establish the format of records in that cylinder. The terms variable block size and ckd are not equivalent. Shmuel (Seymour J.) Metz Username:Chatul (talk) 00:41, 21 June 2010 (UTC)

The 350 on a 305 was addressable to the sector so your statement "IBM's first generation of disk drives read a track at a time" is incorrect, see:305 RAMAC Programmers Guide pg. 8. Again I really don't understand what "self formatting" drives mean so I am not sure what point you are trying to make. I suspect you are trying to say something like IBMs early disk drives had a factory set fixed addressable block size but subsequent subsystems (beginning 1301?) allowed the addressable block size to be set for a disk drive by the customer or application and then later subsystems allowed the addressable block size to vary on a drive (beginning S/360?) or something like that. However, I really think this is WP:TMI for this article, possibly WP:OR and probably too much even for the History of hard drives article. Tom94022 (talk) 04:25, 21 June 2010 (UTC)

The 355 was part of IBM's first generation, so my statement was partially correct; I should have used a qualifier.

I was trying to say what I wrote, i.e., not all of the early disk drives had sector orientation. I suppose that you could claim that a full track was a sector, but when it comes to the 1301 there is nothing remotely like sectors. You defined the track layout on a cylinder with set format, and there wasn't even a requirement that all records be of the same size or format.

As for TMI, that's better than incorrect information. Again, my concern is accuracy, and if you want to resolve it by removing the incorrect statements rather than by qualifying them I have no problem with that. Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:57, 21 June 2010 (UTC)

My main point is that this is really way too much detail for this summary paragraph on history. It also needs to be correct. It probably belongs in the Disk formatting article which is totally void of any history prior to PCs. Your point is that the first disk drive like today's disk drives use fixed block architecture where all the blocks (sectors) are the same size and factory preset. Yes a track is a block when that's all you can read/write. Variable block size, that is variable by the user or application, was introduced by IBM with the 1301 and keyed variable block size called Count Key Data (CKD) was introduced by IBM with System/360. Most computer systems used fixed block sizes. Variable block formats fell out of use during the 1990s - with IBMs ECKD Extended CKD the smallest block is one track. Or words to that effect. Tom94022 (talk) 17:00, 21 June 2010 (UTC)

Reseting the margin

No, my point is that not all disks are sector oriented and that the text of the article should be changed to reflect that fact. I don't really care whether that is done by expanding the existing text to make it correct or by removing the text that is not universally true, as long as the result is accurate.

Please name one disk drive manufactured today that does not have fixed block size, usually 512 bytes, but sometimes a bit larger like 520. The industry is struggling with how to go to 4 KiB, see <http://www.anandtech.com/show/2888 Western Digital’s Advanced Format: The 4K Sector Transition Begins>, 12/18/2009. Tom94022 (talk) 18:04, 23 June 2010 (UTC)

Variable block formats did not fall out of use in the 1990's, at least on IBM mainframes. Your claim about ECKD is incorrect; the organization of data on the track for ECKD is the same as for CKD. IMHO the details belong in the article on CKD, unless that would be TMI, but not in this article.

I agree that any such material belongs in the Drive format and or Count Key Data articles. I was quoting an IBM article about the "smallest block size" and can't find it right now but the point is that at one time disk drives were written with variable block sizes, even on one track, but today the block size is fixed and the variation in file size is accommodated in the system or disk storage subsystem. So from an HDD viewpoint, variable block formats DID fall out of use in the 1990's - the last such HDD being the 3390 that I know of. Tom94022 (talk) 18:04, 23 June 2010 (UTC)

First, the last IBM disk drive that did not have an underlying sector (cell) orientation was the 3350; the 3375 was CKD on top of FBA, as were all subsequent IBM disk drives.

I'm pretty sure you are incorrect about the 3380 and the 3375; please see IBM Mainframe Disk Capacity Table and 3380 Reference Summary. I can speak from personal experience on a PCM 3380 that it was a native CKD machine at the track format ~~and that is my understanding with regard to the 3390~~. It is also my recollection that the 3375 was also native CKD at the track level. The 3370 and the 3375 to the best of my recollection used the same mechanism to be either a fixed block soft sector drive (3370) or a native CKD drive (3375) depending upon the controller which was housed in the first drive of a sting of drive, the so-called A box. Tom94022 (talk) 23:57, 27 June 2010 (UTC)

The capacity calculations for the 3375, 3380 and 3390 all involve rounding up to cell sizes. Shmuel (Seymour J.) Metz Username:Chatul (talk) 12:39, 29 June 2010 (UTC)

Further research suggests the 3390 was a fixed block drive, see 3390 Reference Summary. My guess is then that it was also a hard sectored machine. Tom94022 (talk) 00:48, 28 June 2010 (UTC)

Still further research makes it unclear as to the track format of the 3390 - in the IBM RAMAC Virtual Array manual a section labeled "Traditional DASD" (p 92) depicts a 3390 as an example with native CKD track format. Tom94022 (talk) 03:23, 28 June 2010 (UTC)

Final research, per IBM 3390 Direct Access Storage Introduction GC26-4537-03, Fourth Edition, May 1993, "All 3390 models store data using the count-key-data record format." Furthermore, Figure 8 shows 15 read write heads and one servo head suggesting this is a dedicated servo drive so the entire track is available allowing either CKD or soft sector, depending upon the controller, that is, there does not appear to be hard servo sectors. Tom94022 (talk) 04:04, 28 June 2010 (UTC)

Except in CE manuals, IBM normally documents its hardware in terms of what the programmer controls or sees, rather than the underlying implementation. Shmuel (Seymour J.) Metz Username:Chatul (talk) 12:39, 29 June 2010 (UTC)

Second, I believe that even on the 3375 and later disks the error codes were at the record level rather than the sector level.

All native CKD machines since the 3330 have ECCs on the count key and data fields. That does raise the interesting question of where are the ECCs on a CKD record emulated on a fixed sector machine. I suspect there are none other than the ECCs on the sectors. Tom94022 (talk) 23:57, 27 June 2010 (UTC)

Third, there should be a discussion of the hard sector versus soft sector issue.

Why in this document; that's way TMI? Any soft sector machine could be formatted with any block size up to a full track or could also be a CKD machine - it depended upon the controller. However, hard sector machines were initially limited in the choices of block sizes but that limitation went away with split field recording - nonetheless the HDD industry remained at 512 byte blocks because of OS limitations until just recently. Tom94022 (talk) 23:57, 27 June 2010 (UTC)

Shmuel (Seymour J.) Metz Username:Chatul (talk) 01:35, 27 June 2010 (UTC)

What you may be thinking of is that modern DASD controllers have large caches and that reads of single blocks are often satisfied from the cache, but that is true for both CKD and ECKD. You might also be thinking of the fact that modern ECKD disks are simulated on top of FBA disks, but that is invisible to the programmer except for capacity calculations. Shmuel (Seymour J.) Metz Username:Chatul (talk) 17:40, 21 June 2010 (UTC)

As you note, the CKD and ECKD simulate variable block sizes (and keys) onto fixed block size HDDs meaning there are no more variable block size HDDs, subsystems maybe, but no HDDS! Tom94022 (talk) 18:04, 23 June 2010 (UTC)

So what I intend to do is add a brief summary section on [Disk formatting] in either the Technology or the Market Segmentation section, linked to the [Disk formatting] article, and then correct that article to add the history as we have discussed above. The disputed paragraph will be deleted from the History Section. If u disagree let me know. Tom94022 (talk) 23:46, 25 June 2010 (UTC)

See above.

For some of the self formatting disk drives the logic was in the controller rather than the drive. Shmuel (Seymour J.) Metz Username:Chatul (talk) 01:35, 27 June 2010 (UTC)

The logic has always been in the controller; beginning in the 1970s, the controller started to get integrated into the drive (called intelligent drives in the industry) and by the middle of the 90s there were no more dumb drives. About the same time the industry went from dedicated servos to sectorized servos which more or less killed soft sectors and native CKD since the block size was constrained by the hard servo sectors. Again, the invention of split field recording eliminated this constraint but that didn't resurrect CKD or change the block size. But this is really TMI Tom94022 (talk) 23:57, 27 June 2010 (UTC)

I believe that we may be talking at cross purposes. I used the term controller to refer to the control unit attached to the channel, e.g., IBM 3880; you appear to be using the term to refer to the head of string. Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:03, 29 June 2010 (UTC)

I see more discussion but no objection so I am going ahead. Tom94022 (talk) 23:57, 27 June 2010 (UTC)

- Changes have been made to the HDD article and to the Disk formatting article that should resolve this issue. Please feel free to further edit there. Tom94022 (talk) 20:14, 28 June 2010 (UTC)

I've edited formatting and added a link to ECKD, without mentioning it by name. In the process I noticed that there are separate Count Key Data and Extended Count Key Data articles; should they be combined? If not, is there any reason to not cross link them?

Also, I've noticed that ECKD redirects to Count Key Datainstead of to Extended Count Key Data. I'll try to get to those in the near future, but if you have time, ...Shmuel (Seymour J.) Metz Username:Chatul (talk) 12:39, 29 June 2010 (UTC)

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