Talk:SD card/Archive 2

This is an archive of past discussions about SD card. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2

Incorrect pinouts for microSD

The SPI pinouts listed in table format seem to be for SD and incorrect for microSD (even though it claims it applies to all 3 standards, it doesn't seem that way). Please refer to:

edit: fixed Anthiety (talk) 18:53, 7 January 2013 (UTC)

I was the one that created the tables in this article and originally wrote the electrical section per what I dug out of the official specs. I think the problem is those other web sites have a different pin numbering scheme compared to the photos in this article. http://en.wikipedia.org/wiki/File:Micro_SD_card_pinning.jpg I don't have time at this exact second to validate, but wanted to quickly drop my initial thoughts here. • Sbmeirow • Talk • 20:37, 7 January 2013 (UTC)

I didn't create the photos with the numbers in this article. They were added after I created the tables. I just now sent off a email to sdcard.org to ask for a reference. I was in contact with them with I wrote the electrical section. • Sbmeirow • Talk • 21:07, 7 January 2013 (UTC)

We need to determine the correct answer (with proof), then correct the TEXT and/or PHOTO to match it. Don't get in a big rush....discuss....then do it right. • Sbmeirow • Talk • 21:07, 7 January 2013 (UTC)

It does seem like that is the case, and that the 9-pin configuration for mini- and micro-SD may no longer be used or standard. All of the diagrams from the reference links and general schematic & image searches seem to indicate mini- and micro-SD have only pins 1-8, sitting flush (no offset 9th pin). When you get time can you double-check if this is indeed the case and if so update the mini and micro SD images so they reflect the current standard? Anthiety (talk) 21:19, 7 January 2013 (UTC)

Here are the internals of some microSD/miniSD to SD adapters, which shows how the pins are connected to each other: • Sbmeirow • Talk • 21:23, 7 January 2013 (UTC)

http://www.camerahacker.com/Digital/Inside_miniSD_Adapter.shtml

http://club.dx.com/forums/forums.dx/threadid.412614

http://en.wikipedia.org/wiki/File:SD-microSD_adaptor.jpg

Indeed, all of them are of the 8-pin variety. I'm not going to re-edit it, I'll let you do that to maintain page consistency, but I think we have the facts now. edit: I see the current image does have 8 pins, the first of which is labelled 9 (#3 missing). Again, in all of the references I've encountered they've never numbered the pins like that. Usually numbering the pins from 1 to 8 starting on the left. For example, page 4: http://www.digitalspirit.org/file/index.php/obj-download/docs/sd/Kingmax_microsd.pdf Anthiety (talk) 21:27, 7 January 2013 (UTC)

Just to give a quick picture of what's going on, this is an example of the overwhelming consensus of the microSD (transflash?) pins:

I am hard-pressed to find anything which disagrees with this or supports the pin assignment of the current images. Anthiety (talk) 21:45, 7 January 2013 (UTC)

For Wikipedia, what matters is...does it match the official SD Card specification? If we can't get SD Card specs, then we'll step back to SD card makers and SD socket makers for their numbering scheme...which likely matches the official specification. The lowest reliability is blogs and various other non-official website....they might be a good source but they aren't official. SD card makers and SD socket makers have to pay a license to SD Card Association, so they are likely the closest non-official source for pin numbering. • Sbmeirow • Talk • 21:54, 7 January 2013 (UTC)

Going over the official SD association standards, they make several references to DAT[0:3] pins but never seem to actually mention physically where these pins must be:

I assume it's either not standard - the physical layout of the pins - or it's not in the freely available specifications. As you said I'm inclined to believe the actual card makers since they pay the licensing and in any case set the de-facto standard. All the manufacturer published specs seem to agree on the commonly found pin layout (1-8 starting from left), another example:

http://www.dtt8.com/images/micro-sd%20specification.pdf

Anthiety (talk) 22:18, 7 January 2013 (UTC)

I sent an email to my last contact at sdcard.org requesting a reference for us to link on their website (for proof). Hopefully they will help us out, but they also might not. I'll respond HERE after I get a response from them. Also, I'll do more investigation tonight and hope other people join this discusion. • Sbmeirow • Talk • 22:07, 7 January 2013 (UTC)

What does matter for Wikipedia though is that it report not "what-ought", but rather what-is. Very likely all signs point to the standard agreeing with the manufacturers, but in any case, the article should properly explain how SD is actually used and implemented. Towards that, I'm inclined to favor WP:BOLD here and push for an immediate change (i.e. not wait for a standard which is likely not to come for free or in any short order). I'd say update the page to reflect the overwhelming consensus among manufacturers, implementers, schematic diagrams and users. If and when you're able to obtain the full standard we can update the page with any new information, but in the meantime the current state of the article does not represent the current state of the industry's implementation of microSD.Anthiety (talk) 22:18, 7 January 2013 (UTC)

I didn't ask for the full specification, because I'm very aware that it costs money. We need to ensure BOTH the microSD and miniSD are correct. It does seem the numbering in the photo doesn't match the microSD card vendors, but at the same time the article is technically correct between the numbers in the photos VS the numbers in the tables, so it's not like everything is out of whack. That part of the article has been in its current state for a long time, thus 1 or 2 day delay is no big deal in comparison. I have invited a couple of other editors to comment. • Sbmeirow • Talk • 22:55, 7 January 2013 (UTC)

I added some TEMPORARY text under each photo to buy us some time to get this fixed. • Sbmeirow • Talk • 23:08, 7 January 2013 (UTC)

Sbmeirow, thanks for asking me to join this discussion. But I have no information with which to disagree with Anthiety. My role in this material was only clerical reformatting. Good luck in finding out what the right answers are. Spike-from-NH (talk) 23:39, 7 January 2013 (UTC)

I'd also like to point out the urgency here since it's more of a disservice to pass off wholly inaccurate information as accurate rather than having some (stated) inaccuracies. If at least we should put a disclaimer stating that the current information is highly discrepant with what's out there, then others can find this information easily. However since this article is currently easier to reference than any other (even the standards themselves) I think the longer we wait the more people (such as myself) are going to be burned by misinformation (literally, in this context inaccuracies can result in burning). I didn't focus too much on miniSD so I agree that it presents a less clear picture (I think 1 or 2 references seem to indicate the current pin mapping, a few others the microSD mapping). But I think with some searching around it should be as easy to clear up as microSD. However I think we have an overwhelming amount of information pointing to the correct microSD pin layout. I think we should get that information presented as hastily as possible, even if it's accompanied by a disclaimerAnthiety (talk) 23:47, 7 January 2013 (UTC)

What disservice or urgency? I've already added a TEMPORARY note under the photo to TEMPORARILY address this issue, which is good enough until it gets fixed. This is NOT an end-of-the-world issue, so PLEASE don't treat it in such a manor! • Sbmeirow • Talk • 01:05, 8 January 2013 (UTC)

Second that. The only problem here that needs to be fixed at once is someone trusting Wikipedia. For all you know, everyone who has edited this page is being paid by the Bubble Memory Cartel (Slogan: "We'll be back!") to spread false information about SD cards.

When you read something on Wikipedia, you should think "that's interesting. I wonder if it's true. Time to check the citations!" While Wikipedia is usually quite reliable, there is a reason why people get flunked or fired for relying on it. Take a look at Wikipedia:List of hoaxes on Wikipedia if you have any doubts. --Guy Macon (talk) 05:50, 8 January 2013 (UTC)

I got a reply from SD Card Association. They don't have any public drawings on their site for us to reference. It cost zero for me to ask, so no loss. • Sbmeirow • Talk • 09:00, 8 January 2013 (UTC)

I'm currently working on 3 new drawings to replace the current 3 photos. I need a couple more evenings to finish them. • Sbmeirow • Talk • 09:00, 8 January 2013 (UTC)

I made these changes to this section: add 2 new columms, add 2 new rows, center items in table, change from tables on 1 row to 2 rows (because tables are too wide now). • Sbmeirow • Talk • 06:26, 9 January 2013 (UTC)

I added my new drawing and removed the previous 3 photos. It took longer to complete because I was experimenting with colors / fonts / various ways to present the cards. I added a MMC column to the tables too. • Sbmeirow • Talk • 15:05, 17 January 2013 (UTC)

4 Gb SDSC bis

Noq today correctly reverts Anon as "unsourced," but it was more than unsourced, it was overt advocacy based on personal anecdote. The article already documented the potential problems with using SDSC cards above 1 Gb and even gave the technical reasons; we should not go further into recommendations, either that they are "most worthwhile" or about their availability "despite rumors to the contrary." Regarding Anon's material about the behavior under Win9x, we recently correctly deleted text I had added about write-protected SDs under those old operating systems. Spike-from-NH (talk) 15:20, 20 January 2013 (UTC)

Write Protect Switch

A word about the purely mechanic write protect switch might be practical. Knowing its function (just for a switch in the reader; lower part of cutout only to hold switch, otherwise not needed) allows you to easily fix a broken off and missing write protect switch by scotch tape with a little piece of solid cardboard, wood or paper clip underneath. – Fritz Jörn (talk) 09:41, 22 March 2013 (UTC)

I think we have enough of a word now (at Section 2.2.1) that a reader would see how to work around a broken switch as you describe. Spike-from-NH (talk)

PS--On 16-May, Zedtwitz added text that SD readers detect this tab optically and not mechanically, achieving higher reliability through the absence of moving parts in the reader. I deleted this contribution, asking in the Change Summary whether the SD spec mandates this implementation of a card reader, and even so, whether the article wants to start describing the rationales behind engineering decisions. "What they specified" is easier for us to document than "what they were thinking," as there are sometimes good arguments for and against engineering decisions. Spike-from-NH (talk) 12:02, 29 May 2013 (UTC)

I cannot find anywhere in any spec that optical vs mechanical is specified. --Guy Macon (talk) 07:47, 30 May 2013 (UTC)

nanoSD

Sbmeirow and Anon are having a revert war over dimensions for a form factor called "nanoSD." My Google search turns up matches that, on the first page, cease to have anything to do with data storage, including an offer on alibaba.com for something alternately called "nano SD" and "nano SIM"--but also a blog at craptastic.net "to collect and share funny (but fake) products that parody or satire real ones" [1]. I conclude that there may be a SIM card with this name and with an adaptor to SD form factors, but (especially as it is not in the SD specification), it is not properly in this article, any more than SD should be in the CompactFlash article because you can buy an adaptor to make it look like a CompactFlash. Spike-from-NH (talk) 11:42, 20 December 2012 (UTC)

http://rookery.s3.amazonaws.com/3316000/3316302_6c93_1024x2000.jpg ;P

It appears to me that some Chinese manufacturers did a web search for "nano SD", "nano SDHC", etc. found multiple sites that mention "iPod nano SD" or "iPod nano SDHC", and assumed that the "nano" was a prefix for the card, not part of the Apple product name. It is common for vendors on alibaba.com to list products for sale that they don't actually have. The theory is that you list hundreds of product names, and when you get a big order you start looking for a source.

I see no convincing evidence that a nano SD card exists.

http://www.google.com/search?q=NanoSD

http://www.google.com/search?q=NanoSD+FemtoSD

http://www.google.com/search?q=NanoSD+FemtoSD+AttoSD

http://www.google.com/search?q=NanoSD+FemtoSD+AttoSD+ZeptoSD

http://www.google.com/search?q=NanoSD+FemtoSD+AttoSD+ZeptoSD+YoctoSD

--Guy Macon (talk) 16:20, 20 December 2012 (UTC)

Then we would both agree with Sbmeirow in keeping nano's dimensions out of the article. Spike-from-NH (talk) 18:22, 20 December 2012 (UTC)

Yes. If the IP editor tries to re-insert it, revert on sight with an edit comment that invites him to discuss it here. If he reverts again, give him a user warning with Template:Uw-3rr, and if he hits 4RR, report him at Wikipedia:Administrators' noticeboard/Edit warring. Please note that such reports are rejected if the user was not warned before the 4th revert, and multiple warnings are better. --Guy Macon (talk) 23:22, 20 December 2012 (UTC)

Thanks for each of your investigations. I did the same thing before I reverted the first time, including searching for official SD documents and rumors. The nanoSD is some bastardized concept that is stealing the SD name to promote itself. I also wonder if it was SIM related, but in the end I don't care because it's not official and didn't belong in this article. Even if SD Card Association is working on a new spec or concept, we can't include it until we have some type of official proof. • Sbmeirow • Talk • 00:09, 21 December 2012 (UTC)

Your guess about the source being the Apple iPhone sounds like an even better reason. Good job! • Sbmeirow • Talk • 00:13, 21 December 2012 (UTC)

Just for fun I repeated the search. Nope. No such thing. --Guy Macon (talk) 07:52, 30 May 2013 (UTC)

Fakes

Elvey, in the section on Fakes, has reinserted wording that is tighter than his original (13-Apr) that the SD "marketplace is rife with defective, counterfeit products." I have no doubt that fraud exists, but do doubt that we can quantify its magnitude (in numbers or in words) compared to the market at large. And surely fake cards fail in all the ways he has listed. But his sources are all blogs--he now cites three now rather than just one. I can blog anything I like, then quote my personal opinion. He asserts in the Change Summary that "Some blogs meet RS. Cited one does."--which to me is yet another personal opinion.

It is unremarkable to me that, if you buy a branded product and someone defrauds you, the product will not perform as you expect from that brand. Is there anything authoritative we can say about it besides, "Beware!"? Elvey accuses me in the History of being a seller of fakes. (Anyone who pages through the History sees that my edits are not merely to make the world safe for fraudsters.) It is he who seems to be on a campaign. Spike-from-NH (talk) 12:02, 29 May 2013 (UTC)

I didn't accuse you of being a seller of fakes; I asked a question which you've answered, but I'm sorry if you took offense, Spike.--Elvey (talk) 18:56, 29 May 2013 (UTC)

You wrote in your change summary: Are you a seller of frankenflash? Yes, it is a question and not an assertion, but either implies that my edit was made to achieve personal gain, which is offensive. Spike-from-NH (talk) 10:55, 30 May 2013 (UTC)

Spike-from-NH is a well-respected Wikipedian who has a reputation for doing good work on technical topics. Implying that he is a seller of fake SD cards is not only deeply offensive, but also completely unsupported by any evidence. --Guy Macon (talk) 11:47, 30 May 2013 (UTC)

To the extent that my English was flawed, and allows an interpretation that implies Spike is a seller of fakes, I apologize. In the English language as I know it, and I know it very, very well, I didn't accuse Spike of being a seller of fakes; I asked a question which he's answered, and I didn't imply that he is a seller of fake SD cards either. --Elvey (talk) 06:51, 5 June 2013 (UTC)

This is original research, and thus not a suitable source for editing the article, but a while back I was running compatibility tests on SD cards. I bought well over two hundred different cards from a wide variety of manufacturers and from different sources (buying the same model from Amazon, eBay and Newegg is a good way to get different lot numbers). I don't believe I got any fakes, and I certainly did not get any cards with mislabeled capacity (my tests would definitely have found that). Rife with defective, counterfeit products? Not really. Now I do buy from reliable vendors; if I had picked new eBay sellers with bad reputations and too-good-to-be-true prices, or bought from Craigslist, a local swap meet or the back of a truck somewhere, I might very well have ended up with a pile of fakes.

:As for the accusation, I have placed a friendly warning on his talk page. If the behavior continues, please drop me a line on my talk page and I will escalate it to the proper venue. --Guy Macon (talk)

I have nothing to do with the sources I referenced; the list of ebay fake flash sellers is crowdsourced; certainly the claims are readily verifiable by looking up all or a sampling of the >1600 the ebay sellers. 'Some blogs meet RS' is fact, not personal opinion. Whether the cited one does is a separate question. Guy, bunnie fount the marketplace was rife with fake microSD cards when he went looking for 'em. (And if you want to insist that even bunnie's blog isn't a RS, http://www.gizmodo.com.au/2010/02/even-kingston-knocks-off-kingston-microsd-cards/ or boingboing have roughly the same story. And, "rife" is long since gone from the article; didn't bother to read what I'd actually written, clearly.) --Elvey (talk) 20:57, 29 May 2013 (UTC)

Elvey, some blogs and forum posts can meet our criteria for RS, but most of them don't. For example, anything posted anonymously or under a pseudonym does not qualify. And for a forum or blog to qualify, the site and the author should have built up a reputation for quality over years. Also, the links should be static and the likelihood, that the site will continue to exist (without changing the link structure) in a number of years, should be high. Ideally, the site should be non-commercial and free of ads. Finally, if the information can be found elsewhere in RS, we should use these sources instead.

I'm sure the problem has been discussed in reliable sources like printed computer or photo magazines already, so we should use them. (I could certainly provide some RS, but they are not English and therefore I leave it to others to find English RS). --Matthiaspaul (talk) 22:29, 29 May 2013 (UTC)

It appears that Elvey has decided to respond to my warning[2] with defiance.[3] As I said before, if he repeats the behavior, let me know and I will see to it that is is addressed appropriately. ( "Experience is a dear teacher, but fools will learn at no other." --Benjamin Franklin ). I also see that Elvey has decided to use reverts in an attempt to get his way.[4][5] I undid his revert[6] and encourage him to seek consensus on the talk page. Given his previous violations of Wikipedia policy,[7][8] we may have to deal with edit warring or sockpuppetry,[9] but so far he has not crossed that line. --Guy Macon (talk) 02:16, 30 May 2013 (UTC)

I see you have responded to my warning with defiance, Guy. If you're going to threaten me here, then you need to respond to my warning on your talk page.--Elvey (talk) 02:45, 30 May 2013 (UTC)

If you have a specific problem with the heise, gizmodo or boingboing references, state them. Guy keeps removing ~~even these~~ refs. If he continues to refuse to discuss the specific references, reverting, e.g. simply restoring "Such fakes have been around since at least 2007.<ref>{{cite web|url=http://www.heise.de/mobil/meldung/Gefaelschte-SD-Karten-151283.html}}</ref>" (What's wrong with that???) doesn't constitute edit warring. --Elvey (talk) 03:11, 30 May 2013 (UTC)

Don't you love the way these (Personal attack removed)s call a single edit "Guy keeps removing..."? It's as if they can't wrap their minds around the concept of an editor who actually follows WP:BRD --Guy Macon (talk) 06:50, 30 May 2013 (UTC)

Elvey had replaced the above with "[removed personal attack]"--a comment which, still affixed to Macon's signature, seemed to be Macon's statement that he was removing some other personal attack rather than getting censored himself. Indeed, Macon was not making a personal attack but saying he was pursuing Wikipedia policy and Elvey is not, also criticizing Elvey for overstating the number of reverts that actually occurred. Above, Elvey apologizes to me, in the form: "I'm sorry if my English was flawed so as to lead you to interpret it erroneously, though there is nothing wrong with my English." In the article, Elvey now gives a better citation for his assertion that there is fraud in the market for SD chips; but the assertion itself still strikes me as unremarkable. Spike-from-NH (talk)

I reworded the section to give it about as much weight as the similar sections in Rolex, and Prada, which is being generous -- both have a far bigger counterfeiting problem than SD cards do. Louis Vuitton and Montblanc don't mention fakes at all. nor does Microprocessor --Guy Macon (talk) 08:02, 6 June 2013 (UTC)

[I've removed my last responses here and on our respective talk pages since Guy has accepted my suggestion we "get back to building an encyclopedia [rather than] engage in conflict."] --Elvey (talk) 09:04, 7 June 2013 (UTC)

I have ~~stricken~~ my comments above concerning Elvey. He says he wants to get back to building an encyclopedia and so do I. If anyone wishes me to remove rather than strike, I would need to see a general consensus for that. I consider this to be resolved and unless someone has any objections, I am going to collapse this section and mark it resolved in a day or so. --Guy Macon (talk)

Thanks. Please don't collapse it; just let MiszaBots care of it.--Elvey (talk) 01:38, 8 June 2013 (UTC)

refinements - prevalence, location

Regarding moving: Moving it to a section retitled "Markets" makes sense, otherwise I don't think moving it puts it under a more appropriate heading. I found a media source (heise but 2013) confirming indicating the problem is still common, so let's add it: http://translate.google.com/translate?hl=en&sl=de&u=http://www.heise.de/mobil/meldung/Smartphones-waehlerisch-bei-microSDHC-Karten-1825259.html If you shop around for the best deal, pricewise, on what you're looking for in an SD card, you'll probably get a fake. There's plenty of evidence of it being a big problem in sources with OR and RS issues, so I think saying that it's 'common', as heise reports, avoids the appearance of whitewashing. --Elvey (talk) 18:45, 9 June 2013 (UTC)

"Features" section

This section has become de-organized since my rewrite of last year:

The sentence at the start of "Card security" used to be an overview of the following material, but it was reorganized so that there is nothing beneath it.
The sentence at the start of "Read-only cards" did look like an overview of what follows, but it should not be; it describes commands to the SD card about which nothing more is said later.
The section on the write-protect tab now begins by copying text from the preceding section, including the phrase, "The host device can command the SD card" though security via tab has nothing to do with host commands.

I've changed this section to correct these problems, intending not to change any of the substance. Spike-from-NH (talk) 12:30, 8 June 2013 (UTC)

PS--I would hate to reopen the previous can of worms, but such information as we elect to have on Fakes does not belong at the end of the section on History. A better location would be at the end of the section on Market penetration or at the end of the section on Types of cards. Spike-from-NH (talk) 12:34, 8 June 2013 (UTC)

PPS--Elvey's "boldly tightening wording" of my edit was elegant. Based on his concurrence in a preceding section, I've moved Fakes to underneath Market penetration. Spike-from-NH (talk) 01:08, 10 June 2013 (UTC)

Thanks. Appreciate your recent edit to my edit too. --Elvey (talk) 07:29, 26 June 2013 (UTC)

Android sdcard?

Android machines appear to have some reserved storage they call 'sdcard' but is internal and visible to users. I THINK it's part of ordinary internal storage, but I'm not an expert. For example, the earlyNexis, which has no external SDcard capability at all, refers to items in sdcard. It appears to be a subdirectory of user storage, or rather the top level subdirectory visible to users.

If you add a real SDcard, then it's usually referred to as extsd or something similar. This might be worth a paragraph because I came here looking for answers and didn't find one. --71.1.200.230 (talk) 22:43, 10 June 2013 (UTC)

Usually? I've seen only Android machines that mount sd cards in /sdcard, IIRC. And I'd say such info belongs on a page specificaly about Android technology, not here.--Elvey (talk) 07:29, 26 June 2013 (UTC)

OS handling of read-only media

I removed this from the article:

Using a read-only device in Microsoft Windows may produce errors because, even when merely reading a file, Windows tries to write a timestamp to the device. (Comparable behavior by Linux can be disabled, and doing so reduces the number of writes to the SD card.)

This is incorrect information and was flagged by a citation needed template for over a year. Windows drivers do not exhibit this behavior; they know not to attempt a metadata write on a read-only device. Linux drivers behave the same way. And, although the advice about disabling update of the last-referenced date information is valid, this article is not a Linux how-to. Discussing the prevention of write operations seems confusing (and a bit odd) in a section on read-only devices. — UncleBubba ^{( T @ C )} 07:53, 20 October 2012 (UTC)

As you are correct even back to WinXP, I concur. I seem to recall the Blue Screen of Death under Win95 and maybe Win98, but this error in OS's from two decades ago certainly says nothing about the SD card. Spike-from-NH (talk) 11:43, 20 October 2012 (UTC)

I don't think this was an issue with 95 or 98 either. I used a switch in the IDE cable to write protect my secondary hard drive on DOS, 95, and 98 (you can't protect the windows boot drive, of course). I don't remember whether I switched to SATA before or after switching to XP (I tend to be a late adopter of Windows versions). Microsoft has a KB on this at [ http://support.microsoft.com/kb/331895 ]. Also see [ http://www.digitalintelligence.com/products/ultrakit/ ] which is used by police departments to read hard drives without any chance of erasure. --Guy Macon (talk) 00:25, 21 December 2012 (UTC)

While this is not related to SD cards specifically, I would still like to add that the statement "Using a read-only device in Microsoft Windows may produce errors because, even when merely reading a file, Windows tries to write a timestamp to the device." is in fact true!

Some versions of Windows attempt to write to a medium even on seemingly read-only disk accesses. This goes unnoticed in most cases, but it can also have fatal consequences. There are three known areas affected:

OEM label (boot sector) - removable media under Windows 95, 95B, 98, 98SE, ME
MBR disk timestamp - partitioned media under Windows 95B, 98, 98SE, ME
MBR disk signature - partitioned media under Windows NT 3.5 up to at least Windows 7

In the first case, Windows overwrites the OEM label in the boot sector whenever a freshly inserted medium is not write-protected, even on something trivial like a "DIR A:". While the OEM label is officially documented as "not used by operating systems and free for OEM use", many Microsoft and IBM operating systems (including MS-DOS/PC DOS 3.1 (and higher), OS/2 as well as Windows 95, 98, SE, ME) undocumentedly use it in order to determine the format of the BPB in the boot sector and which BPB entries they trust. Untrusted entries are ignored and recalculated from other entries, and sometimes they are modified on the fly even if they were correct in the first place. This can lead to the odd situation that the BPB values are perfectly okay and the operating system would just have to use them, but instead those operating systems are no longer able to recognize them for what they are because they overwrote the OEM label in the first place. Instead of using the provided correct BPB values, they will then calculate faulty values to the effect that the mounted media can no longer be accessed at all or appear to have a completely trashed filesystem. Windows then typically gives misleading error messages like "Cannot read sector" etc. as if the media were physically defective, while in reality they are logically and physically intact (except for the OEM label, which, by definition, should be don't care for the operating system). Non-Microsoft and -IBM operating systems can still access such media without problems, of course, but most users will assume their media were faulty...

In the second and third case, Windows undocumentedly overwrites certain areas in the Master Boot Record, which are normally used by the boot loader. This can make these volumes unbootable.

--Matthiaspaul (talk) 16:57, 26 June 2013 (UTC)

The above is useful information--but is mostly information on very old operating systems that is not specific to SD, the basis on which I agreed with the original removal of the paragraph. Spike-from-NH (talk)

Yes, it's unrelated to SD cards and therefore does not belong into this article. I just wanted to correct the statement above. --Matthiaspaul (talk) 08:44, 28 June 2013 (UTC)

This talk page eventually gets archived; can you put that information somewhere in mainspace where it can be found? Spike-from-NH (talk)

SDHC/SDXC incompatibilities

I concur with Reatlas in reverting Luigiacruz today. The new paragraph went from informative to normative (using "should" to give advice to the SD user). The section describes in detail the possible problems in using a newer family of SD card in an older device, and there is a preview of it in the Introduction. Spike-from-NH (talk) 13:53, 25 August 2013 (UTC)

Using SDXC cards on SDHC hosts

Back when we migrated from SD to SDHC, I found many devices would not read or write SDHC cards.

I presumed the move from SDHC to SDXC would introduce the same incompatibilities. However, my tests so far suggest that SDHC host controllers typically DO support SDXC. On inserting the Kingston 64GB Micro SDXC card to Android, it recognises the card as unformatted. Accept format (which writes a FAT32 file system). Tested with two MTK6589 based Android phones, Allwinner A31 based Android tablet, RK3066 based Android TV, February 2010 HTC Desire G7 A8181. I have not yet found an incompatible SDHC controller if formatted with Fat32. I'm not suggesting that there aren't incompatible controllers, but my tests suggest a good level of compatibility at least on devices with firmware capable of handling Fat32 file systems of over 32Gb.Nick Hill (talk) 22:18, 28 January 2014 (UTC)

The invention of SDHC redefined fields to force a change to the way the controller computes sector addressing, introducing problems that are now stated at Section 7 of the article. The invention of SDXC did not do the same thing; it introduced features that a controller for SDHC cards would not know about, but didn't change anything about operating the SDXC as an SDHC. However, your observations might not hold on all SDHC devices, because the specification allowed the device to assume that no card would ever exceed 32GB. Spike-from-NH (talk) 23:58, 29 January 2014 (UTC)

SDXC Capacity Discussion

Discusion about official capacity of SDXC cards. I feel the article should follow the official description of SDXC from sdcard.org instead of what some SD card maker does.

These sdcard.org webpages state >32GB:

Pretec says they are selling 32GB SDXC (which I say is unofficial):

If you drill down through all the current Pretec products, you won't see any SDXC cards smaller than 64GB. I'll bet that sdcard.org put a thumb down on them, per SD license agreements.

http://www.pretec.com/products/memory-cards/sd-card

• Sbmeirow • Talk • 20:31, 23 February 2014 (UTC)

I agree. I now realise that the contradiction I'm trying to resolve here on this page is actually just mirrored from the real situation! I've attempted to capture this in my re-edit. I hope you accept this. —James Haigh (talk) 2014-02-23T20:44:36Z

SDHC shortsighteness?

Anyone know the thinking behind SDHC? It's maximum capacity of 32GB doesn't seem like that big of a leap from the previous 2GB limitation. And SDXC was introduced just three years later. --209.203.125.162 (talk) 01:47, 17 December 2013 (UTC)

An increase to the power of five and it took three years to upgrade it? Sounds reasonable. Especially considering that the difference between SD and SDHC is (((x^2)^2))*2 and the difference between SDHC and SDXC is only (x^2)*2 — Preceding unsigned comment added by Xnamkcor (talk • contribs) 04:49, 13 March 2014 (UTC)

Shortsightedness is understandable, especially given that the original market for SSFDC chips was, literally, making a Solid State Floppy Disk (0.00144 GB) replacement. I imagine that, at the time SDHC was adopted, putting your entire movie collection on a single chip was not a criterion. If something is at Sector 1000, there is a reluctance to render it as Sector 0000001000, everywhere, based on what the future might bring. Also, engineers sometimes underestimate how the first product to market becomes the de-facto standard, even when international standards committees are working to do it "right." The fits and starts in this technology induced me to use USB for anything over 2 GB. Spike-from-NH (talk) 14:18, 13 March 2014 (UTC)

Should we even try to imagine the cost and time issues with releasing SDHC to be able to have a max capacity closer to 512GB?xnamkcor (talk) 01:38, 16 March 2014 (UTC)

Changing the original specification would have entailed no additional cost or time — but some manufacturers would not have embraced it if it forced them to also support hypothetical and unrealistically (at the time) large chips. Changing it now is impossible, as manufacturers are guaranteed there will never be an SDHC over 32 GB. Spike-from-NH (talk) 12:42, 16 March 2014 (UTC)

Split

Discussion closed: consensus is clearly against splitting.

The following discussion has been closed. Please do not modify it.

Added this section per article split request that someone else requested. • Sbmeirow • Talk • 10:10, 10 February 2014 (UTC)

"It has been suggested that this article be split into articles titled SDHC and SDXC, accessible from a disambiguation page. (February 2014)"

Where would the SD cards go? --Guy Macon (talk) 10:21, 10 February 2014 (UTC)

The suggestor is Rx5674. I don't agree with the suggestion. Most of the technical material and all of the history is common to all three products, and the key usefulness of this article — the presentation of incompatibilities — is vital for all three. I don't see how an article on SDHC would benefit from omitting the history of "SDSC" and the development of SDXC. No one goes out to buy an SDHC card; one buys an SD card that happens to be SDHC. One might set out to avoid buying an SDXC card, depending on the intended device, and if he consulted Wikipedia first, he would be better served seeing information on the complete spectrum of products than reading about SDHC alone. Spike-from-NH (talk) 13:59, 10 February 2014 (UTC)

USB 3.0 is also splitted becuase it is a major revision. The differences of SD/SDHC/SDXC should be written in three articles.--Rx5674 (talk) 14:48, 10 February 2014 (UTC)

USB has it's own article (USB) that covers all versions, plus an additional article (USB 3.0) that focuses on one version. In addition, we have a number of redirects, including:

USB 3.0 (Separate article, not a redirect), and

USB 3.1.

We should handle Secure Digital the same way; keep the one article (Secure Digital) that covers all versions, and if any editor wants to, they are free to create a separate article focusing in on just SDHC or just SDXC. That new article would, of course, have to meet our notability standards. --Guy Macon (talk) 17:08, 10 February 2014 (UTC)

I don't think it should be split for similar reason as Spike-from-NH. • Sbmeirow • Talk • 00:52, 11 February 2014 (UTC)

No split. It's always a red flag for me when an editor flags an article for a major change like a split, merge, neutrality disputed, whatever, and then doesn't care enough to start the required discussion on the talk page to explain the action. I agree with editors Spike-from-NH and Sbmeirow, and Guy Macon. Keep the current main article intact with its useful comparison charts, and like Guy Macon says, anyone can try to write a separate article if they want and then provide a "main article" link in the appropriate section here. 5Q5 (talk) 16:55, 31 March 2014 (UTC)

I am closing this discussion. Consensus is clearly against splitting. --Guy Macon (talk) 17:29, 31 March 2014 (UTC)

Photo of counterfeit

Having not heard back from editor Metareview in a week, I have removed the photo of a counterfeit SD card that he added. Apart from documenting his personal experience, it doesn't add anything to the article. Spike-from-NH (talk) 09:46, 9 April 2014 (UTC)

Apart from documenting Spike-from-NH personal experience, it surely adds something. Metareview (talk) 08:55, 12 April 2014 (UTC)

Sir: Parroting my words back to me is not a rebuttal, and it would be fascinating to know what your personal testimonial adds. (There are slightly more details in my post to Metareview's talk page, which he deleted.) Spike-from-NH (talk) 11:10, 25 April 2014 (UTC)

Separately, now, Landroo asserts on the page that some fake SD chips mimic correct operation using the owner's hard disk "until after the feedback reporting period expires for some online buying sites." This is entirely anecdotal, is offered without citation, and would be outrageously complicated engineering for a retail scam. Landroo leaves the three citations (two in German), but the one I can read doesn't disclose anything this sinister. Presumably his fakes have detected that he has posted to Wikipedia and will now install pop-ups in his browser? Spike-from-NH (talk) 11:10, 25 April 2014 (UTC)

Ultra High Speed bus

I've edited the introduction of SDXC in Overview to move all references to the problems with exFAT into the subsection (currently 1.3.1) and delete the conclusion of the "unsuitability" of SDXC. I retained the statement that SDXC is not a universal exchange medium to SDXC readers (though this is unremarkable, as no SD card is a universal exchange medium to readers designed for an earlier generation of SD card).

Now, someone has moved Ultra High Speed bus into the Overview. While UHS may be a big engineering feature, this reorganization conflicts with our consensus last year that the article burdened the user with technical details early on. I think that this section belongs inside Speeds, and that all of Speeds belongs lower in the article. The Overview properly describes the major device types, and it would be followed by Features, things that are also highly visible to the user. The discussion of whether a given card can deliver acceptable throughput is important to the article but it is really a technical detail, like the interface and compatibility issues we discuss later in the article. Would like discussion before doing this gut-and-paste. Spike-from-NH (talk) 12:29, 17 June 2014 (UTC)

No-one uses these Features, they are mostly useless. Writing speeds and card bus speeds are far more important, as they directly impact end-user performance with most photo/video equipment that requires fast cards, and that's why they are given prominent markings by the creators of the standard. --92.242.59.6 (talk) 12:46, 18 June 2014 (UTC)

Older SD cards

I just listed a 32MB SD card (as part of a bundle of SD cards) on eBay. Looking at the back, I have noticed that it has a lot more pins than you show in your diagrams. I think it has about 14 or 15 pins depending on how you count them.--TonyTheTiger (T / C / WP:FOUR / WP:CHICAGO / WP:WAWARD) 01:09, 1 August 2014 (UTC)

Sounds like an MMCplus card rather than an SD card. --Matthiaspaul (talk) 01:34, 1 August 2014 (UTC)

You are correct. On the front it says MMC Plus.--TonyTheTiger (T / C / WP:FOUR / WP:CHICAGO / WP:WAWARD) 01:51, 1 August 2014 (UTC)

SD is based on MMC, but they both evolved differently, thus is why I didn't include the various MMC styles in the drawing in this article. The MMCplus is an evolution of the MMC. • Sbmeirow • Talk • 01:58, 6 August 2014 (UTC)

UHS Host Devices ?

I've had a quick google, but found nothing that will actually take real advantage of UHS cards. They will work in SDHC, but not at their best. Is it a dead non-adopted standard ? Seems odd !

--195.137.93.171 (talk) 15:05, 28 August 2013 (UTC)

Found one - Nikon D600

Presumably it's an emergent standard, just in its infancy.

--195.137.93.171 (talk) 11:59, 1 September 2013 (UTC)

Most newer cameras from 2013 support UHS-I. For UHS-II there is a card reader from Panasonic.

AJ-MPD1G

Angerdan (talk) 07:36, 2 September 2013 (UTC)

Appears to be intended for video. I don't see an advantage on a still camera. Kortoso (talk) 23:15, 26 September 2014 (UTC)

Use of SPI mode withput a license

It is stated repeatedly throughout the article that host controllers can access SD cards through the SPI mode without needing to obtain a license. I am curious if there is any reputable source we can supply, which confirms that the SD Organization actually permits royalty-free use of their intellectual property with respect to hosts accessing SD cards via SPI.

I am aware that the simplified specification is supplied without requiring developers to sign a license agreement, and I am also aware that various reverse-engineering efforts succeeded in determining most of the SPI command set even before the simplified specification was released. However, if you visit the SD Association's web page, they clearly state that their decision to publish the simplified specification does not constitute a grant of any license to implement patented methods described by the specification. Reverse-engineering has never conveyed permission to implement patented methods.

If the SD Association really has made a promise to permit royalty-free host implementations over SPI, then it would be very useful to provide a link to confirm this fact.24.222.2.222 (talk) 12:57, 27 November 2014 (UTC)

I contacted SD Association a couple years ago and the person said that I didn't need a license to create a product that interfaced to SD card slots using SPI-bus. I think primarily because SPI-bus is kind of an "open bus". I seem to remember asking for the same proof, but I can't remember if there was any, anyway I haven't spent any time digging through their site to see if their ever clarified it. • Sbmeirow • Talk • 21:46, 28 November 2014 (UTC)

If you want to make and sell an SD card, then you need a license. If you want to add SD-bus capability to an IC chip so it can communicate with an SD card, then I think you need a license. If you want to use their symbol, I think you need a license. I'm not a lawyer, nor a SD Association representative, so you should contact them for accurate answers for specific license questions. • Sbmeirow • Talk • 21:46, 28 November 2014 (UTC)

I am not a lawyer nor an expert, but it strikes me that SPI is the prior art and SD cards were designed to be backward-compatible with it. Serial Peripheral Interface Bus says this is a de facto standard with no established publication defining it. (Section 5 of that article says that implementations vary widely.) This suggests that the SD Association does not even own this interface mode, in which case it might not be prepared to "promise to permit royalty-free" use of it. Spike-from-NH (talk) 23:48, 28 November 2014 (UTC)

versus eMMC and SSD

How would these be ranked in terms of best and worst? Would it be SSD (solid state drive) > SD card (secure digital) > eMMC (embedded MultiMedia card/controller) or some other order? Is SD better than HDD (hard disk drive)? Is eMMC better than HDD? --64.228.88.135 (talk) 00:16, 1 December 2014 (UTC)

What's better, train or bicycle? It depends on the criteria (f.e. purpose, usability, compatibility, size, speed, capacity, age, reliability, costs) used for the comparison. They cannot reasonably be compared except for in a particular context of application. --Matthiaspaul (talk) 16:27, 14 January 2015 (UTC)

Another point is that SD cards use for storage the same technology as SSDs, that is Flash memory. The main difference is that the interfaces are different. Interfaces are usually classed by speed, as this is the main factor. In the case of UHS-II it is 312 MB/s[10], while with SATA-3.2 it is 2GB/s[11]. So SATA is capable of the faster access, but of course these figures are in practice a lot lower, as flash memory is usually slower than either of these figures.

Traditional hard drives are usually slower than flash memory, but of course this won't always be the case, it depends very much on the technology used. And MMC technology is outdated[12], and a lot slower than SD or SATA.

So it is MMC < SD < SATA, if you look at peak performance from the latest standards. And usually HDD < flash memory, but this won't always be the case. Note that MMC and SD are always flash memory (I think) and SATA drives can be flash memory or hard disks. --Mrjulesd (talk) 17:25, 14 January 2015 (UTC)

"A SD"

Sdxu has just globally changed "An SD" (pronounced "an ess dee," I think) to "A SD" (pronounced "a SecureDigital"? I think not), change summary "corrected grammars." I've reverted; I brought up this question, without response, so long ago it's now archived. If there is a policy on this, I don't insist; but after Sdxu's change, it just looks wrong. Spike-from-NH (talk) 14:23, 14 January 2015 (UTC)

The rule to append an "n" to the indefinite article "a" is based on how the first letter of the immediately following word is pronounced, not how it is spelled. If the sound starts with a vowel, an "n" is added, otherwise not. Therefore, "an SD card" is correct. As English pronunciation can differ in different parts of world, this can sometimes cause confusion, but AFAI see it should not in this particular case. --Matthiaspaul (talk) 16:15, 14 January 2015 (UTC)

Oh, Matthiaspaul is right, I did think about it awhile before editing, but I bear the word "secure" when thinking a or an, but not "s", which apparently "secure" got no vowel at the front. It's about the "reading practice": when reading some acronyms which apparently have pronunciation, it goes, but when there is no, I return back to the long form, especially only a few or 2 letters. I check back Oxford Advanced Learner's Dictionary (British's), it's as Matthiaspaul said, follows how the first letter is said, but then the 2nd question comes: article a got 2 pronunciation forms: "normal" or strong form, what Spick-from-NH talks about is the strong form. I think it's ok to have a or an, but make it ALL a or an. It's not good to have a and an at the same time in an article. No need to be too serious on this. Language is changing, at a slow pace. — Preceding unsigned comment added by Sdxu (talk • contribs) 06:36, 15 January 2015 (UTC)

On a glance, there is no mention of how SD pronounced in article, or there is really an official pronunciation? How about the a or an SDIO? SDHC, SDXC? Just make it consistent and it'll be ok. Sdxu (talk) 06:43, 15 January 2015 (UTC)

While going to excuse, I think about this story and got the answer why I read the long form: I have been reading computer or Microsoft material in these 18 years, about 10,000 pages. And there is lots of acronyms, maybe 100, even in 1 single 1000-page book. Some only mentioned once, twice, or times I can count. And they are similar and sometimes short, 2 letters, 3 letters, or even the SAME. There is no use to talk in acronyms, even to another who is familiar with Microsoft's: we can't catch the acronyms in talking (at first). So I changed to read the long form for ALL acronyms not instantaneously recognized. That's why I read the long form in SD. Hope it adds info to your journey in a and an. Sdxu (talk) 07:45, 15 January 2015 (UTC)

Since they lack vowels immediately after the "S", saying one letter at a time is typical, like "S" - "D", or "S" - "D" - "H" - "C". • Sbmeirow • Talk • 08:16, 15 January 2015 (UTC)

SDIO, SDHC and SDXC

I just made a modest merger of three short paragraphs on SanDisk announcements of successively higher-capacity devices, but it strikes me that the section has become a long catalog of company product announcements with declining relevance to the reader. In fact, some of the earlier announcements will lead no one to read the citation in the footnote because some of these products must have been retired by now. Someone with better understanding of the technology's real milestones (and dead ends) should pare this down. Spike-from-NH (talk) 12:34, 9 March 2015 (UTC)

Good Article Nomination?

Came across this article in my regular course of reading and think it deserves to be nominated for a Good Article. Thoughts regular editors? Sam.hill7 (talk) 19:26, 11 March 2015 (UTC) comment added by Sam.hill7 (talk • contribs) 03:45, 16 January 2015 (UTC)

FAT32X

I am in a revert tussle with Be..anyone. I presume (though do not know for sure) that the two successive list items seek to distinguish between an SD using FAT32 and an SD using FAT32X. I post-edited him with a piped redirect, to make the link he edited continue to appear as "FAT32X" but he said this was a BAD bypass redirect. FAT32X redirects to FAT32, but is nevertheless what this article should have in this position, which doesn't depend on whether a unique page exists. More knowledgeable editors need to give opinions at this point. Spike-from-NH (talk) 01:15, 23 April 2015 (UTC)

I bypassed the redirect, and so it was my bypass that would be bad if FAT32X could be something different from FAT32 now ending up at exactly the same section. The difference is only the partition type for LBA already covered here and again at the redirect target. It's exactly the same file system, and on GPT disks (no MBR/EBR) or superfloppies (no partitions) the different MBR/EBR partition types don't exist. –Be..anyone (talk) 07:18, 23 April 2015 (UTC)

Yes, they appear to be "exactly the same file system," but the article on FAT32 says that "FAT32X...indicate[s] usage of LBA disk access instead of CHS." I assume the previous editor meant something by writing [[FAT32X]] in this one case, and that is why I corrected your correction to say [[FAT32|FAT32X]]. Spike-from-NH (talk) 10:53, 23 April 2015 (UTC)

x86 systems not supporting LBA and limited to CHS are twenty years old and long dead. The devices supporting Secure Digital memory cards are not affected by old x86 history and 16-bit arithmetic. There is only one semi-official FAT32 specification, published by Microsoft for the purposes of UEFI. The FAT32X term is a marketing term used by two vendors of partition software, nobody else needs this WP:NEO for any practical purpose. –Be..anyone (talk) 07:26, 24 April 2015 (UTC)

Free formatters

80.1.145.168 reports/asks in the text of the article:

There are several free PC applications available online for formatting USB drives such as HP USB Disk Format Tool , 2Tware Fat32Format , and miniAide Fat32 Formatter. ^[1] Does this imply that exFAT is NOT so mandatory as stated here. Is the said mandatory FS a commercial 'deal'?

I am not sure a list of software tools should be in the text of the article, but am sure a broadcast to other editors should not be. On the query itself: In general, the existence of pirate software does not imply that piracy is now acceptable. Two of the tools refer in their names to FAT32, which makes no assertion about exFAT. If these tools are mentioned on a sandisk.com page and if they support exFAT, it may mean that the conditions for use of exFAT have changed, but I don't know that. Spike-from-NH (talk) 16:17, 28 June 2015 (UTC)

^ http://kb-eu.sandisk.com/app/answers/detail/a_id/10505

Copy protection

I don't understand how the copy protection can work. When the card sends out the data, it can neither tell nor control if the data is just displayed / played or copied to another card or drive. — Preceding unsigned comment added by 82.139.82.82 (talk) 03:21, 8 July 2015 (UTC)

As I understand it, the card refuses to "send out the data" under protection until the requesting software identifies itself with reference to information in the reserved area of the card, using an op-code that is not in the public specification. The size of the reserved area gives the card the ability to require a different authorization for each transaction and makes it harder for unauthorized software to pose as the correct software. Spike-from-NH (talk) 14:32, 9 July 2015 (UTC)

Confusing sentence about guarantees of limits

It is said in this article:

> Compliance with a higher speed rating is a guarantee that the card limits its use of the "busy" indication.

That doesn't seem to make any sense. Limits its use of the busy indication to what? 91.2.78.8 (talk) 19:22, 14 January 2016 (UTC)

SDIO

The SDIO section might need a separate article, it doesn't exactly fit here (see last row in the compatibility table). –Be..anyone (talk) 23:09, 11 April 2016 (UTC)

MB or GB for 2005?

This edit changed MB to GB, but has no source, so I'm not sure which is right. I tried reading more, but Flash_memory#Capacity made me even more confused in some ways. Also, it seems like capacity has not improved much since then if 128GB was available back in 2005? I realize maybe they're talking about different things, but I'm not sure. I feel it's unclear or hard to follow which products are being discussed when capacities are being discussed in general when numbers pop up all over in paragraph form. Thanks for any reply:) Zeniff (talk) 10:14, 22 August 2016 (UTC)

Thanks for the hint! microSD started with capacities of 8 MB. SDXC (including microSDXC) was published in 2009. One of the features of SDXC was to support cards larger than 32 GB. The first 64 GB SDXC card (not microSDXC!) was announced in 2009 and hit the market in 2010.

The IP must have confused with this CompactFlash cards, which were available in larger capacities and much earlier - 128 GB were supported since CF 1.0 as of 1994/1995 already (and 128 PB since CF 5.0 as of 2010), but such large cards did not became available until much later.

--Matthiaspaul (talk) 12:52, 25 August 2016 (UTC)

External links modified

Hello fellow Wikipedians,

I have just modified one external link on Secure Digital. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

Added archive https://web.archive.org/web/20080916035153/http://www.sandisk.com:80/Assets/File/pdf/retail/SDHC1.pdf to http://www.sandisk.com/Assets/File/pdf/retail/SDHC1.pdf

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

Y An editor has reviewed this edit and fixed any errors that were found.

If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 07:55, 9 November 2016 (UTC)

Technically irrelevant table row?

(INAL) In table "Comparison of technical features of MMC and SD card variants", the row "Open-source compatible" DO NOT make any sense at all. — Preceding unsigned comment added by Kuldeepdhaka (talk • contribs) 20:59, 16 April 2017 (UTC)

Proposal to include section on standards adherence

Upon reading this, I find that these values are idealized and gathered from specification documents. In practice, however, I have found it extremely rare for a device to actually adhere to the stated writing speeds. I recently bought a card from a prominent global brand and by using the Linux application dd (Unix) to pipe massive amounts random data sourced from a file to the card, I have only seen one card that actually delivered as promised (using a 4GiB card back in 2007). I think a detailed and reproducible description of the evaluation and certification procedure would also be a valuable addition. Timothy D Legg, 87.138.223.233 (talk) 08:23, 30 May 2017 (UTC)

Does this article Say anywhere

that the maximum capacity of an SDSC card is 2GB? Because if it does i can't see it. And it should. Flagpolewiki (talk) 16:29, 23 November 2017 (UTC)

it's in the upper-right infobox. • Sbmeirow • Talk • 16:50, 25 November 2017 (UTC)

Rename to SD card

Per WP:COMMONNAME, the term "SD card" is arguably more used and easily more recognizable than "Secure Digital". I think the article's title should change to reflect this.~ Arkhandar ^{(message me)} 17:24, 8 February 2019 (UTC)

On Google Trends, for example, it's clear that Secure Digital is far from the common name; it's beyond residual compared to SD card. I'm going to go ahead and WP:BOLD this change. ~ Arkhandar ^{(message me)} 17:32, 8 February 2019 (UTC)

Requested move 8 February 2019

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this section.

The result of the move request was: Moved — Amakuru (talk) 17:21, 15 February 2019 (UTC)

Secure Digital → SD card – Per WP:COMMONNAME, the term "SD card" is arguably more used and easily more recognizable than "Secure Digital". On Google Trends, for example, it's clear that Secure Digital is far from the common name; it's beyond residual compared to SD card. ~ Arkhandar ^{(message me)} 17:35, 8 February 2019 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's policy on article titles.

Support move. This one's so obvious that I'm not sure how it hasn't already been done. ONR (talk) 19:26, 8 February 2019 (UTC)
Support. The acronym is more common and the meaning is not common knowledge, as is USB (and USB flash drive) which are rightfully located at the acronym. I, too, am amazed that there has been no previous RM. Lazz _R 21:33, 10 February 2019 (UTC)
Support per WP:COMMONNAME. Rreagan007 (talk) 05:17, 11 February 2019 (UTC)
Support per WP:COMMONNAME. Calidum 03:12, 14 February 2019 (UTC)

Discussion

Per Wikipedia:Article titles, "When titling articles in specific fields, or with respect to particular problems, there is often previous consensus that can be used as a precedent."

Article name examples:

"MMC card" article is named MultiMediaCard, it isn't an acronym, and doesn't have the word "card" in it.

"CF card" article is named CompactFlash, it isn't an acronym, and doesn't have the word "card" in it.

"MS card" article is named Memory Stick, it isn't an acronym, and doesn't have the word "card" in it.

"SM card" article is named SmartMedia, it isn't an acronym, and doesn't have the word "card" in it.

"UFS card" article is named Universal Flash Storage, it isn't an acronym, and doesn't have the word "card" in it.

"SPI bus" article is named Serial Peripheral Interface, it isn't an acronym, and doesn't have the word "bus" in it.

"I2C bus" article is named I²C, and doesn't have the word "bus" in it.

• Sbmeirow • Talk • 20:56, 8 February 2019 (UTC)

Thanks for the input. I should note though that all of the examples you've provided are considerably niche when compared to the SD card. I would argue that the SD card is almost at the same level of notability as USB, and as is, the article is not name "Universal Serial Bus". ~ Arkhandar ^{(message me)} 11:39, 12 February 2019 (UTC)

Quit picking your favorite thing to rename. Either rename all of the card articles or none. • Sbmeirow • Talk • 17:53, 12 February 2019 (UTC)

@Sbmeirow: I don't have a "favorite thing", and that's not how it works... ~ Arkhandar ^{(message me)} 01:47, 13 February 2019 (UTC)

There is such a thing as article name uniformity on Wikipedia for many topics. • Sbmeirow • Talk • 08:03, 13 February 2019 (UTC)

A few points:

You missed "XD Card" which is actually under the article named xD-Picture Card - it IS an acronym AND has the word "card" in it.

MMC doesn't have "card" in the title as that would be MultiMediaCard Card, a tautology

Memory Sticks were never referred to as cards - I don't remember having seen "Memory Stick Cards" as it simply doesn't sound right.

As there is at least one example of Memory cards where the article uses and acronym & has the word "card" in the title, I see no reason for this change to not go ahead • Ian Devlin • 18:01, 13 February 2019 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

Implemented @Old Naval Rooftops, Lazz R, Rreagan007, and Calidum: please update the article's lead and infobox accordingly. --Ahecht (TALK
PAGE) 20:52, 15 February 2019 (UTC)

organization vs organisation

Concerning organization vs organisation spelling change on edit https://en.wikipedia.org/w/index.php?title=SD_card&type=revision&diff=946645178&oldid=943430460

It should continue to be spelled with "z" because of "MOS:RETAIN". • Sbmeirow • Talk • 20:16, 21 March 2020 (UTC)

Not forgetting MOS:COMMONALITY Dondervogel 2 (talk) 20:23, 21 March 2020 (UTC)

SD Card Formatting/Imaging Software: Raspberry Pi uses Etcher

The $35 credit card sized Raspberry Pi computer by default uses a micro SD card as its primary disk. Novice Raspberry Pi users are likely to turn to Wikipedia to find out more about SD and Micro SD cards. It would be helpful if they saw a reference to the recommended software: Etcher.

"Mac and Linux users typically use the dd command in the terminal, while Windows users require a program such as Win32DiskImager.

So we were pleased to come across Etcher. Etcher turns the whole process of flashing an OS image file into three simple steps: Select Image, Select Drive, and Flash Image.

More importantly, the same program, with the same interface, is available on all three types of computer – Windows, Mac, and Linux – which makes it easy for everybody to understand." ^[1]

"Etcher has completed over one million writes, collected nearly 3,000 stars on GitHub, and made its way into many official installation and getting started guides. It’s become one of the most reliable and, we think, pleasant ways to burn SD cards.

Etcher has also proven to be really valuable for image publishers like the Raspberry Pi Foundation. As Matt Richardson says, "Since its initial beta release, Etcher has quickly become an indispensable tool for our community. It runs beautifully on multiple platforms, has a user-friendly design, and is extremely reliable. Etcher is an excellent choice for our users to get up and running with Raspberry Pi. Etcher's ease-of-use is especially helpful to achieve the aims of our charitable mission and makes an educational impact because it removes barriers for new users who are just getting started." ^[2]

So, if anyone can boil this marketing hype down to concise information for Wikipedia readers that would be helpful. Jim.Callahan,Orlando (talk) 20:26, 12 June 2020 (UTC)

Discontinuation of 8GB,4GB,2GB,1GB microSD and SD cards

Hello, I really need to such information but don't know what phrase I should enter for search, please someone do search and provide several sources about it or suggest several phrase for searching. I just know 1GB microSD and 2GB microSD are discontinued/ceased and are no longer in production, but what about 4GB? and 8GB? is there any website or primary source to provide information about the discontinued capacity of microSD cards and the year of its discontinuation?. Such information can also be added to the article. -- THANX. Editor-1 (talk) 08:42, 17 August 2019 (UTC)

Such information can be added to the article and it would be very useful, so please help if you can, thanks.--Editor-1 (talk) 13:41, 10 September 2020 (UTC)

Disputed: 32 GB FAT32 limit

§ exFAT filesystem says that some SDXC host devices reject FAT32 file systems larger than 32 GB. That's been marked as needing a citation since September 2017 and although it's certainly possible (software may be arbitrarily perverse), it seems remarkably unlikely. Any objection to replacing it with a weaker statement that since such a file system violates the specification, it's not guaranteed to work? 209.209.238.189 (talk) 08:23, 21 December 2018 (UTC)

FAT32 on sdxc is not "endorsed" by the sd organization, but any sensible host should be able to read it. Wiekendraak (talk) 21:50, 28 December 2020 (UTC)

Powers of 1000 vs 1024

Closing zombie discussion being weaponized to try and fork conversations across the wiki. Continue discussion at WT:MOSNUM. —Locke Cole • t • c 16:41, 3 May 2021 (UTC)

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Why are the capacities in the thumbnail descriptions given in powers of 1000 (or 10^x where x is an int), e.g MB, GB, TB, while elsewhere they are in powers of 1024 (or 2^x where x % 10 = 0), e.g MiB, GiB, TiB? I'm concerned because as the capacities increase, esp for TB vs TiB and PB vs PiB, the difference in bytes is huge.

Highlighted inconsitencies of powers of 1000 and 1024, in revision https://en.wikipedia.org/w/index.php?title=SD_card&oldid=957885871

Fezzy1347 (talk) 17:12, 25 May 2020 (UTC)

Good question. My (limited) understanding is that the maximum capacities are binary (see exFAT), but that the published capacities are decimal. Dondervogel 2 (talk) 19:27, 25 May 2020 (UTC)

As noted by Fezzy1347 the difference is important. Hence the revert. Dondervogel 2 (talk) 10:14, 3 May 2021 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

@Fezzy1347: @Locke Cole: This thread has been transferred to WT:MOSNUM. Dondervogel 2 (talk) 09:25, 7 May 2021 (UTC)

[1] ttp://kb-eu.sandisk.com/app/answers/detail/a_id/10505

[2] ttps://magpi.raspberrypi.org/articles/pi-sd-etcher

[3] ttps://www.balena.io/blog/etcher-1-0-is-here/

[1]

[1]

[2]