Talk:Comparison of memory cards

Where's SD?

I guess I will try to add that column in the next day or two. --WhiteDragon 05:08, 17 August 2006 (UTC)

ok, I'm blind. In my defense, it's late and I haven't had enough sleep :-P --WhiteDragon 05:09, 17 August 2006 (UTC)

Changed microSD Maximum storage capacity due to inconsistency with http://en.wikipedia.org/wiki/MicroSD

CompactFlash Out of Date?

I was just looking at this page and I notice a few things that seem out of date. I'd try editing myself but I don't really feel all that qualified on this subject.

1. The maximum for CompactFlash is listed as 12000MB but Sandisk currently has a 16GB card out. Is that because it's hasn't actually shipped yet? I notice that bhphotovideo.com says it is estimated to be available in November, which has passed.
2. The flash technology for CF is listed as NOR but I'm pretty sure that modern CF cards are NAND. If I am correct, maybe it should read NOR or NAND?: Please provide a verifiable reference to these 2 facts, for example, press-releases of major manufacturing companies. There are lots of hoaxes on high-capacity memory cards, such as counterfeits of SONY USB flashes that claim to be 8GB, but are 64MB in reality. For the NOR/NAND - if it's true and verifiable - let's add it as "NOR or NAND"? --GreyCat 10:20, 7 December 2006 (UTC)

For the Sandisk 16GB card, the Sandisk website should be believable shouldn't it?

http://www.sandisk.com/Products/Item(2207)-SDCFX3-16384-SanDisk_Extreme_III_CompactFlash_16GB.aspx

I just checked and bhphotovideo.com now has them listed in stock:

http://www.bhphotovideo.com/bnh/controller/home?O=1097&A=details&Q=&sku=461865&is=REG&addedTroughType=categoryNavigation

I've dealt with them for around 15 years and they have always been above board as far as I can tell -- which makes them unique among N.Y. mail order camera shops.

I can't find a reference on the NAND/NOR thing. Sandisk doesn't seem to have it on their site that I can find nor do they have a support email that I can find, just a phone number. I suppose I can call tomorrow. Billdav 06:30, 12 December 2006 (UTC)

1. Someone added a category at the bottom of the chart for bootable PATA-CF adapters. Addonics has had a bootable SATA-CF adapter available for quite a while now. I'm not sure if that should be added.

I believe that that section should be reworked completely. There's myriads of adapters possible and available. It would be very

1. I have been unable to determine from the Sandisk web site if the big Sandisk CF cards (8/12/16GB) are CF-I or CF-II. —The preceding unsigned comment was added by Billdav (talk • contribs) 20:39, 6 December 2006 (UTC).

I just got of the phone with a Sandisk support rep and he told me that Sandisk no longer makes CF type 2 cards at all. They are all CF type 1, even the 16GB. He had to go ask someone for that information.

Neither he, nor the people he had to help him knew the answer to the NAND/NOR question. He gave me an email address (oemsales@sandisk.com) that he believes will get me in touch with someone who can answer that question. I sent the email and added the question if there are any online sources of this information. Billdav 01:07, 13 December 2006 (UTC)

...

OK. I got a reply. The NAND/NOR thing is true. It has switched over to NAND. This can be found in the SanDisk CompactFlash Memory Card Product Manual Version 11.0, Document 20-10-00038, Page 1-4, Section 1.6.3. It can be retrieved from here:

http://www.sandisk.com/Assets/File/OEM/Manuals/ProdManCFlashv11.0.pdf

There doesn't seem to be anything in there about the big cards only being type I now so I suppose that would be considered hearsay from a Sandisk support rep.

Wikipedia's Compactflash page also says that it has switched over to NAND (second paragraph in the article).

Sandisk provides several of their OEM manuals here:

http://www.sandisk.com/Oem/Manuals/ Billdav 18:19, 13 December 2006 (UTC)

Who is to say one way or another? CompactFlash is an interface and doesn't mandate that memory cells be made of any specific material. If they could make flash memory out of tree bark, I'm sure it could be made to interface with CompactFlash. The 4 gigabyte MicroDrive I own is CompactFlash, and it surely is neither. The argument as to whether it's NAND or NOR or anything else is moot. Reswobslc 07:19, 9 January 2007 (UTC)

More info on tables from SD articles

Tables extracted from SD articles:

	SD Memory Card	miniSD Card	microSD Card
Width	24 mm	20 mm	11 mm
Length	32 mm	21.5 mm	15 mm
Thickness	2.1 mm	1.4 mm	1 mm
Card Volume	1,596 mm3	589 mm3	165 mm3
Weight	Approx. 2 g	Approx. 1 g	Approx. 0.5 g
Operating Voltage	2.7 - 3.6 V	2.7 - 3.6 V	2.7 - 3.6 V
Write-protect Switch	YES	NO	NO
Terminal Guards	YES	NO	NO
Number of Pins	9 pins	11 pins	8 pins

Technical comparison

Type	MMC	RS-MMC	MMC Plus	SecureMMC	SD	SDIO	miniSD	microSD
SD Socket	Yes	Mechanical adapter	Yes	Yes	Yes	Yes	Electro-mechanical adapter	Electro-mechanical adapter
Pins	7	7	13	7	9	9	11	8
Form factor	Thin	Thin/short	Thin	Thin	Thick (exceptions possible)	Thick	Narrow/short/thin	Narrow/short/extrathin
Width	24 mm	24 mm	24 mm	24 mm	24 mm	24 mm	20 mm	11 mm
Length	32 mm	18 mm	32 mm	32 mm	32 mm	32 mm+	21.5 mm	15 mm
Thickness	1.4 mm	1.4 mm	1.4 mm	1.4 mm	2.1 mm (exceptions possible)	2.1 mm	1.4 mm	1 mm
SPI mode	Optional	Optional	Optional	Required	Required	Required	Required	Optional
1 bit mode	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
4 bit mode	No	No	Yes	?	Optional	Optional	Optional	Optional
8 bit mode	No	No	Yes	?	No	No	No	No
Xfer clock	0–20 MHz	0–20 MHz	0–52 MHz	0–20 MHz?	0–25 MHz - 0–50 MHz	0–25 MHz	0–25 MHz?	0–25 MHz?
Max XFER	20 Mbit/s	20 Mbit/s	416 Mbit/s	20 Mbit/s?	100 Mbit/s - 200 Mbit/s	100 Mbit/s	100 Mbit/s	100 Mbit/s
Max SPI XFR	20 Mbit/s	20 Mbit/s	52 Mbit/s	20 Mbit/s	25 Mbit/s	25 Mbit/s	25 Mbit/s	25 Mbit/s
DRM	No	No	No	Yes	Yes	N/A	Yes	Yes
User encrypt	No	No	No	Yes	No	No	No	No
Simplified Spec	Yes	Yes	No	Not yet?	Yes	Yes	No	No
Memb cost	$2500/yr (not required)				$1500/yr (appears required)
Spec cost	$500		?	?	Member	Member	Member	Member
Host license	No	No	No	No	$1000/yr+memb
Mem card royalties	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
I/O card royalties	N/A	N/A	N/A	N/A	N/A	$1000/yr+memb	N/A	N/A
Open source compatible	Yes	Yes	Yes?	Yes?	SPI only	SPI only	SPI only	SPI only
Type	MMC	RS-MMC	MMC Plus	SecureMMC	SD	SDIO	miniSD	microSD

Table data compiled mostly from simplified versions of MMC and SDIO specifications and other data on SD card and MMC association web sites. Data for other card variations is interpolated.

Capacity limit in all SD/MMC formats appears to be 128 GB in LBA mode (28-bit sector address).

Most, possibly all, current MMC flash memory cards support SPI mode even if not officially required as failure to do so would severely affect compatibility. All cards currently made by SanDisk, Ritek/Ridata, and Kingmax digital appear to support SPI. Also, MMC cards may be electrically identical to SD cards but in a thinner package and with a fuse blown to disable SD functionality (so no SD royalties need to be paid). Some MicroSD cards do not support SPI mode.

--70.111.218.254 14:59, 25 December 2006 (UTC)

The "Technical comparison" table is Template:MultiMediaCard comparison, it is included in the MMC/SD cards articles. It should be merged into this article. Having duplicate tables with potentially (haven't checked) inconsistent data is not a good solution.--87.162.56.93 (talk) 16:12, 14 December 2007 (UTC)

USB flash drives

Earlier today I added USB flash drives to this page but User:GreyCat reverted it with no clear comment as to why. It seems clear to me that USB flash drives ought to be listed in this table. They are not used in all of the places that other flash formats are and of course aren't generally wholly internal to the device which uses them, but they are often competing in the same kind of space.

Please do discuss this further here before just reverting my change. Thanks. - Ian Jackson User:Ijackson.

Hello ;) Please scroll to the bottom of the page, i.e. #Adding USB flash drive. I've left a detailed comment on particularly why I did that and I've invited you to discuss. Also, please stay logged in for your additions to remain credited to your user, not just IP. --GreyCat 00:27, 4 January 2007 (UTC)

I choose not to accept the Wikipedia cookie because I prefer to keep my browsing anonymous as much as possible. It would be nice if there were a straightforward way to only be non-anonymous for edits but in practice since I always use a fixed IP address used only by other non-abusive people there shouldn't be a problem. -- Ian Jackson. 13:30, 4 January 2007 (UTC)

Wouldn't revealing that you use a fixed IP address, as well as publishing that IP address to the world, and giving out your name as well all sort of run counter to your goal of keeping your browsing anonymous? Wouldn't your browsing be much more anonymous if you just accepted the cookie so you could post under a pseudonym and not reveal your IP either? Reswobslc 07:22, 9 January 2007 (UTC)

Adding USB flash drive

Sorry, 193.201.200.170, I've reverted your edits for adding USB flash drive for a moment. This article is about memory cards, not all solid-state computer memory at all. And I don't really see the point of extending this to include USB flash drive: it's a way too general device, it's available from myriads of vendors, in lots of varieties, features, sizes, colors, etc. Most fields in these comparisons just don't apply to it: you've seen it yourself, you'll have to add a lot of "varies" values. --GreyCat 22:11, 3 January 2007 (UTC)

The reason to include it is that for most normal people all of these are similar kinds of thing. There are devices (hosts, readers) which support USB as if it were a kind of flash memory card - both devices which take USB flash as well as actual flash cards and devices which take USB instead of some other kind of flash. Since USB is competing with these other flash formats, it makes sense to include it in this page even if it isn't exactly the same kind of thing.

Note that the only real difference between USB and the other varieties is that USB flash drives do not end up entirely enclosed or entirely inserted into the reader (as opposed to most of the others) and that the form factor of the "external" part isn't specified (yet). The other differences (eg, that it is available from a myriad of vendors) are not reasons not to include it. --iwj

No, it's not. For "most normal people" these devices (memory cards and USB flash drives) are completely different and they have almost non-intersecting target markets. "Memory cards" are storage media for various portable devices; usually such device have only 1 slot for a specific card; "USB flash drives" are aimed at computer market to achieve maximum compatibility. While choosing a device (for example, a camera), it's important factor to decide what card format you should stick to. This article gives comparison information for a you that'll choose such card. I'm pretty sure that 99% of potential readers of these article have zero interest in reading general information about USB flash drives here. --GreyCat 09:14, 5 January 2007 (UTC)

More criticism of your additions:

I have reformatted this from a list to multiple paragraphs to make responding easier (see Wikipedia:Talk_page_guidelines); I hope that's OK. Thanks. --iwj

You've added USB flash drive to the wrong place, ruining the sorting. The cards are sorted by date of introduction, varieties are grouped. "2001" as a date of introduction of USB flash drive is unsourced and anyway, 2001 belongs to the place between SD and xD. I highly doubt that's true.

The 2001 introduction date came from the Wikipedia page USB flash drive. --iwj

It's 1998, judging from that article. --GreyCat 09:14, 5 January 2007 (UTC)

There is no image for USB drive, as there can't be one, as they come in myriads of varieties.

The right answer is to provide a typical image; unfortunately I don't have one to hand right now. --iwj

There's no point adding line for geometric sizes, as they are all varying. It contains zero useful information.

There are minima and current prevalent sizes. If I had a USB flash drive to hand I would measure it. -iwj

"Maximum storage capacity, MB: 16384" is unsourced, badly formatted (no 2007 is need in this table, as space is scarce), and, in reality, it's unlimited. It's possible to chain flash drives to create multiple times such capacity.

I just looked at an online vendor with whose website I was familiar; it seemed more wrong to provide a link to a vendor!

2007 is needed because this information will change rapidly and the individual cells may be changed at different times, so they may be differently out of date.

No, it's not, as visual space is very scarce. In comparison articles generally we assume that whole table is kept up to date, as of current (2007). I'll add that too, just to be clear. --GreyCat 09:14, 5 January 2007 (UTC)

I'm not sure I understand your point about chaining flash drives; normal USB flash drives do not contain a hub and so you can put at most one in each socket; that you can put a hub into a socket and then several flash drives is true but not really relevant here I think. --iwj

There are ones that do contain one, but it's not the point. In fact, I wanted to note that USB

"Theoretical maximum capacity" is not "very large", but also "varying", depending on particular implementation, etc. No point of storing such information.

No, the theoretical maximum capacity is limited by the SCSI command set conveyed by USB mass storage. I wasn't able to quickly find the correct information here but it's clearly very large. --iwj

SCSI standard comes in at least 2 flavors (21-bit and 32-bit LBA), and there are lots of other possible barriers[1], not mentioning that there may be limits imposed by particular USB implementations, operating system, firmware, etc, etc. --GreyCat 09:14, 5 January 2007 (UTC)

"Data read/write speed" is also erroneous (it's not 1, it's 0.8 AFAIR), and in fact, it's a theoretical speed of USB interface, not real speed of underlying flash chips that can be slower. Most USB flash drives don't reach anything near 40 MB/sec.

Are not the other speeds quoted on a similar basis ? I got the 1Mby/s figure from USB flash drive. --iwj

"Low-level access" is also not true, it can vary depending on what flash chips vendor uses. It can be NOR or NAND.

As I understand it from other pages on Wikipedia NAND is more recent and pretty much every USB flash drive uses NAND flash. --iwj

CF also comes in NAND now, but back in 1998 I believe that most of drives were NOR. --GreyCat 09:14, 5 January 2007 (UTC)

"Operating voltage" is also not true, it's a voltage that USB interface provides, not the one that flash chips use.

The "operating voltage" of an interface specification can only specify voltages at the interface, of course. --iwj

"Write protection switch" is "sometimes" that means can't be specified.

Some SD cards don't come with WP switches either, so according to you that would mean that we shouldn't list SD cards ? --iwj

No, SD cards have all other factors beside that. I'll add a note to SD cards though, thanks. --GreyCat 09:14, 5 January 2007 (UTC)

"DRM" = "yes" is not true; most USB drives doesn't include any DRM mechanism; some may include, but it's also "varying".

Err, I should have entered "no" in that box, sorry. That seems to have been a mistake and I have fixed it. There is no facility for DRM in USB Mass Storage as I understand it. Here "USB flash drive" means (obviously) a USB Mass Storage device as described in USB flash drive. If you think that there are DRM standards for USB flash then they should be described in USB flash drive. --iwj

Sorry, but judging from all of the information added, almost everything is either not true or "varying", i.e. can't be specified. What's the point trying to add USB drive to memory cards? May be you should fix all other Wikipedia articles that don't list USB flash drive as memory card? --GreyCat 00:49, 4 January 2007 (UTC)

The fact that USB is more variable in various ways is not a reason for not including it in this table.

Ian, my point is very simple. When a subject is relevant and can be fully described in precise, verifiable facts (may be with only few minor omission and generalizations), then it should be listed. USB flash drive, when added, adds just a whole bunch of "varies" and clutters valuable visual space.

I didn't come across any other Wikipedia articles that claimed to be lists of flash memory formats, but if they are any they should be fixed too IMO. --iwj (Ian Jackson) 13:30, 4 January 2007 (UTC)

If you really insist on adding USB flash here, there is a memory card article that lists various memory card formats. I'd suggest you fix it too if you feel that USB flash drive belongs to memory cards. Anyway, as our dispute seems to not resolve itself out, I'll invite a third party to help us resolve. --GreyCat 09:14, 5 January 2007 (UTC)

Third opinion

I say that USB drives ought to stay as an honorable mention, even if they are not standardly-shaped "cards" in the traditional sense. To the average Joe, about the only difference between a USB device and any other device is that the USB's lack of standardized shape prevents it from being inserted inside a camera - but that's about it. All kinds of new hardware (for example, my new Philips plasma TV) can use a USB thumb drive as a memory card for the viewing of photos... how can this not be an example of the same thing SD/CF/MS cards are used for? Reswobslc 16:26, 5 January 2007 (UTC)

I hardly believe that "all kinds of new hardware (...) can use a USB thumb drive" when things come to cameras, cell phones, etc, where the memory cards are used traditionally. For example, I don't know a single camera that would allow USB flash drives to be used with it. Please see a bit below for proposed resolution. --GreyCat 00:48, 6 January 2007 (UTC)

Fourth Opinion

While it might be kinda interesting to have USB drives as a comparison, I see some problems:

1. They are not (generally) used as removable storage for consumer electronics
2. In many of these tables you can't say anything meaningful about USB, as there is no standardization
3. The page is titled "Comparison of memory cards", not "Comparison of portable data storage". If we include USB flash drives, why not USB microdrives, or for that matter USB hard drive enclosures, floppy disks and ZIP drives?

—Dgies^t c 21:47, 5 January 2007 (UTC)

I deeply agree with you. May be that would be the best idea - let's create a Comparison of portable data storage that will illustrate whole evolution of portable data storages, including ZIP discs, various floppies, portable HDDs, Firewire drives, CD-ROM/RW, DVD-ROM/-R/+R/-RW/+RW/-RAM, etc? That would be the best option, and we can have there lots of more general columns. --GreyCat 00:48, 6 January 2007 (UTC)

As a counter argument I offer the following:

1. USB flash memory isn't used in portable devices due to a lack of standardized size which is mandatory for a portable device. That doesn't put them out of their league though.
2. There is plenty of standardization for USB devices. If there weren't, you'd need a driver for each one. No, instead a USB flash device must follow a spec called "Mass Storage Class". (Incidentally, so must USB readers for all of the other devices that are listed here).
3. People don't think of USB hard drive enclosures, floppy disks, or zip drives as "memory cards". But average people do equate USB thumb drives as being memory cards. They also equate MicroDrives (spinning hard disks in CompactFlash form factor) as being memory cards due to their size, so that blows any sort of pattern. The only pattern is following the common sense of the lay person, who is Wikipedia's audience, and the lay person would probably appreciate a comparison of a USB "memory card" versus another type, even if the USB device doesn't strictly adhere to the same design goals as a typical memory card.

--Reswobslc 07:34, 9 January 2007 (UTC)

Everything's fine, but this article is called "Comparison of memory cards" and, afterall, we're should try to stick to academic style in our wikipedia articles. If some "average Joe" around is calling both "USB flash drive" and "MicroDrive" a "memory card", we can't do so. If we want to make an article that will accomodate needs of average people on comparison of portable storage, I'd strongly suggest making Comparison of portable data storage - that's a neutral name that would suit everybody, and that article won't be burdended with intricate technical details, such as pinouts, chip types, but, instead, it should mention more common ground facts, such as availability, cost per megabyte, popularity, market share, etc. I'll gladly try participating in that article too. --GreyCat 10:04, 9 January 2007 (UTC)

What then, from an "academic perspective", constitutes a "card"? A card is something you play poker with, and only refers to memory thanks to the average Joe. If this article isn't for Joe, then it should be titled "Comparison of Flash memory modules with standardized sizes". But really, this article doesn't stand on its own. It is an offshoot of the Memory card article, which goes as far as to include the "memory cards" for video game consoles such as Playstation and Nintendo's series, as well as floppy disks, Zip disks, MicroDrives, SIM cards for mobile phones, and plenty of others. I didn't start this dispute, I only started paying attention when an outside opinion was requested. Unless you want to start including flash-based video game console cards in this article, I wouldn't suggest arguing what does and does not fit the title from an "academic" (aka your) perspective. The page could probably use a rename to more accurately define its scope. Reswobslc 05:17, 10 January 2007 (UTC)

Responses to Request for Comment

• I'm here in response to your RfC. In looking at the article I see USB drives are linked but aren't listed as a type of "memory card" per se. This seems appropriate. In my view the most common purposes of each are different -- a USB drive usually serves as removable storage (i.e., floppy or CD substitute), while a memory card usually is installed within a device as part of its mass storage. Doubtless there are overlapping cases but these seem to be the most common usage. Hope this response is useful. Raymond Arritt 03:48, 10 January 2007 (UTC)

Proprietary-ness

Another thing I think would be vital information for this article to compare is how proprietary each standard is (which greatly affects price). For example, Memory Stick is made only by Sony and its licensees, while Compact Flash is based on a much more open standard that anyone may use. To me, that's just as much of a factor as any when considering what kind of memory I'd like to use given a choice. Reswobslc 16:37, 5 January 2007 (UTC)

Yes, I agree that it's an important matter and should be reflected somehow. Any detailed ideas on what kind of table / sections we should have? How to measure "proprietarity"? --GreyCat 00:48, 6 January 2007 (UTC)

How about the opposite term, which would be openness. Useful information would include 1-whether the standard is published or private, and 2-whether manufacturing the device requires payment of licensing fees or royalties, and 3-typical cost per megabyte for the same size of card bought from the same place, so the difference in price that greedy closed companies tack on can be clearly seen for what it is. Reswobslc 07:27, 9 January 2007 (UTC)

81 dpi monitor?

I keep seeing references to monitor DPI's that differ from the standard reference of 72 DPI, particularly in the references and HTML-like comments in the article. Shouldn't 72 DPI be used if being to scale on a display actually matters? Reswobslc 16:42, 5 January 2007 (UTC)

81 DPI is somewhat standard resolution nowadays, so I've chosen it. It's 17" screen at 1024*768 (4:3 ratio). Monitor's visible area measures as 321×241 millimeters, thus giving 1024/321*25.4 = 81.0267912772586 DPI. Roughly 81 DPI. --GreyCat 00:48, 6 January 2007 (UTC)

How can you call it a standard when the math doesn't even add up? Monitors "nowadays" as you say are almost exclusively LCD, whose viewable area equals the monitor size exactly. It doesn't make sense to describe DPI to the trillionth of an inch when 321×241 mm, considering the Pythagorean Theorem, comes out to only 15.8 inches - more than a whole inch off! Regardless of whatever your monitor happens to be, a point is 1/72 of an inch by definition - see Point (typography) - and while no rule says these images have to be any specific size, to claim this is a "standard" is like claiming the mustard stain on your pants is in style. Reswobslc 02:21, 11 January 2007 (UTC)

Reswobslc, please calm down and don't take offense. I just stated my rationale, if you have better proposals - please state them. Typographical points has absolutely nothing to do with monitor DPIs - we're talking pixels and inches, not points and inches. There is a simple display dimensions calculator. For example, for an 19" LCD measuring 1280×1024 pixels (I still can't find a good reference on research of what is more popular "nowadays", LCDs or CRTs, and which size and resolution is most popular) it gives you 86.8 DPI - that is albeit closer to 81 than 72. What monitor do you use? Anyway, a really good solution is specifying sizes in mm, like the one described below. I only hope English wikipedia's software would get patch applied soon. --GreyCat 09:12, 11 January 2007 (UTC)

Well, I don't have a typical display setup. For the middle 30" display (2560x1600), the DPI is over 100, and for the two outside displays (21", 1200x1600) it's about 95. I don't suppose I mean to be spazzing out over nothing, but not only is there a tug of war of insistence as to what "is" and "is not" the subject of this article, the 81dpi as a minor detail is repeated so pervasively as to almost seem religious. Like don't eat red meat, and monitors are 81 dpi. Of course, I also feel that way about St. Joseph 81mg aspirin - I always wonder why will 81mg help your heart more so than 80mg, and get suspicious about the motive behind their insistence on using an odd precise number seemingly unnecessarily. I consider it a marketing gimmick. But I suppose it only makes sense about the millimeters setting and to let the browser do the math for each individual system. I suppose a considerable drawback might include the number of thumbnails Wikimedia must cache however - one thumbnail per millimeter setting it sees per image. Unless the browser can do the scaling all on its own, but I'm not totally sure how that works. Reswobslc 18:24, 11 January 2007 (UTC)

Wow, that's a classy setup ;) Sorry for sounding like a fanatic %) Also, I've never heard about 81mg aspirin before %)

As for technical side of "mm" in Mediawiki, AFAIK, there are barely any ways to reliably detect user DPI (there is a trick to create object with CSS size of 1 inch, then query it's pixel size => that would yield DPI estimate, but, sadly, it doesn't work in all browsers reliably), so I think Mediawiki should stick to memorizing desired DPI in user's settings (72, 81, 95 or 96 DPI could be a nice default), then only the minority of users would change it to something else - it won't put heavy loads on server resizing cache. --GreyCat 23:36, 11 January 2007 (UTC)

Greycat did you know that the wikimedia image tag supports other units? For example you can specify mm. This does rely on the client having their screen res set however. --Monotonehell 09:12, 6 January 2007 (UTC)

Sadly, it doesn't :( At least for me. That's what I do

[[Image:Compactflash-512mb.png|43mm]]

This one inserts image without any rescaling, in it's full size and with alternate title="43mm" (seen in "alt" attribute of "img" tag). Sure, I'd rather use proper sizing in mm instead of that ugly DPI-dependent cludges. --GreyCat 10:38, 6 January 2007 (UTC)

Also, [[Wikipedia:Extended image syntax#Size|]] doesn't seem to specify anything else besides "px" :( --GreyCat 10:41, 6 January 2007 (UTC)

Actually scratch that - the patch hasn't been applied to Wikimedia yet. :( --Monotonehell 11:21, 6 January 2007 (UTC)

please

1)merge into this article, the info from the comparison table that appears here http://en.wikipedia.org/wiki/Secure_Digital_Card

2)before merging, check the accuracy of each comparison table, the info between the comparison tables of these two articles are not the same, for example, MMC Plus data transfer is 52Mbit/sec and 416Mbit/sec

the two articles are http://en.wikipedia.org/wiki/Secure_Digital_Card and http://en.wikipedia.org/wiki/Comparison_of_memory_cards

thanks

Micro SD size increased?

Kingmax say, in this webpage, that they will be making 4 GB micro SD cards. GoldenMars have 4 GB product available. DanBeale 11:23, 13 February 2007 (UTC)

xD card transfer rates

The transfer rates for type H xD cards listed on this page are much higher than those listed on the xD card page itself. Which is correct? Arganoid 14:38, 15 February 2007 (UTC)

SD capacity misleading

The table says, that SD can be upto 137 GB, but the Secure_Digital article claims, that even 2GB are a problem and there was a new standard developed, SDHC, which also maxes out at 32 GB.

--Xerces8 20:06, 11 May 2007 (UTC)

Hot and not

Why don't you add a table that will make it quite clear that the reader should not invest in e.g., SM over SD.

E.g., units produced, year vs. card type, worldwide. Jidanni (talk) 02:34, 20 December 2007 (UTC)

Weight of Memeory Stick Micro (M2)

Is it 2 grams? Same as Memeory Stick Duo? Sounds impossible! —Preceding unsigned comment added by 206.186.8.130 (talk) 19:00, 20 February 2008 (UTC)

Beat me to it! According to SonyStyle.com, the weight is "Approx. 1g" so that doesn't help much. All the other online shops I've checked don't even mention the weight.Corky842 (talk) 05:52, 19 March 2008 (UTC)

Memory stick Duo; 1.3 grammes. M2 card: 0.4 grammes. This would be 'original research', but if nobody argues, the info can go in by concensus. 86.176.152.185 (talk) 17:04, 11 February 2011 (UTC)

Transfer speeds are not accurate

I'm pretty sure that SD cards have transfer rates up to 20 megaBYTES per second (20 MB/s) and not 20 Megabits per second. I've seen cards on newegg rated as '133X' which means 133 times the speed of the original CDROM rates. The original 1x CDROM rate was 1 Kilobyte per second (1 KB/s) according to the wikipedia entry on CDROM which would mean that readily available SD Cards have transfer rates of 133 X 150 Kilobytes per second which is 20 Megabytes per second.

Further, the quoted speed of Compact Flash (133 MiB/s) sounds incorrect. The 133x advertised for CF is 133 times, which - as above - means approx 20 MiB/s. Some CF are advertised at 120x - perhaps this is Type I - indicating a different speed of around 17.6MiB/s. 58.175.172.192 (talk) 06:25, 11 July 2009 (UTC) Ross

note that the Technical Details chart says max. 20 MiB/s read/write for SDHC but Sandisk seems to sell an SDHC card rated 30 MiB/s. Please address. —Preceding unsigned comment added by 12.192.94.253 (talk) 19:53, 16 September 2009 (UTC)

References

Theoretical maximum capacity of SDHC cards

I've adjusted the table to show the real theoretical maximum capacity of SDHC cards. If the SD Association didn't limit cards to 32GB, the correct theoretical maximum capacity of a SDHC card would be 2048 GB. I encourage discussion on this point if people disagree, as what use is a theoretical maximum capacity column if it doesn't talk about it's title? NeoThermic (talk) 03:14, 14 July 2008 (UTC)

First, you should provide a reference for your claims. It's not about wikipedia people agree/disagree, but representing solid encyclopedic sourcing :) Second, on a subject, I don't really like "theoretical maximum" capacity column. "Theoretical maximum" is really an infinity, but it's really stopped by one or more barriers, like bit count for various transport layers, SCSI subsystem, operating systems' implementations, etc. I'd like to this column to show clearly which barriers lay on a path to higher capacity and possibly, how to overcome it. --GreyCat (talk) 07:32, 14 July 2008 (UTC)

SDHC should be differentiated from SD in the technical details table. They have different limitations, and devices that work with the older standard don't necessarily work with the new one. So the higher capacity limit for SDHC should be differentiated and documented (with citation). For instance, at the moment some of the devices have actual capacities listed larger than the theoretical maximum because people are mixing SD and SDHC.

It is the actual maximum column that doesn't make much sense to me. What does the actual/theoretical distinction mean? Is the "actual" column just document the largest device made to date (a constantly changing target, and only marginally encyclopedic), or is there some other distinction? Documenting the largest possible device within the individual standard makes perfect sense. Zodon (talk) 23:47, 21 August 2008 (UTC)

Width and length of microSD and MMCmicro cards

The width and length column values for microSD and MMCmicro cards should be swapped. If the pins of any of the two cards are facing up, horizontal measurements of these cards are smaller than the vertical measurements.

The "microSD" article (Technical comparison table on the page http://en.wikipedia.org/wiki/MicroSD) correctly states that the width of the microSD card is 11 mm and the length is 15 mm. —Preceding unsigned comment added by SakiTC (talk • contribs) 13:19, 4 September 2008 (UTC)

Maximum size of microSD

The maximum size of microSD was claimed to be 16 GB and was flagged as needing a citation. I added a reference to SanDisk's 16 GB product page, but realized this page has a separate row for microSDHC; therefore my citation (and the original 16 GB claim) might be incorrect. I believe the maximum size of the non-HC microSD format is something like 2 GB. Should the 16 GB claim (along with my citation) be removed? Super_C (talk) 18:24, 13 October 2008 (UTC)

After looking a little more, I went ahead and made the change I proposed above. Because there is a row in the grid showing 16 GB to be the maximum size of microSDHC, I changed the maximum size of microSD to be 2 GB (with a reference to the SanDisk microSD/microSDHC product listing). Super_C (talk) 18:38, 13 October 2008 (UTC)

2009 updates - SxS and SDXC

I've just been doing a bit of research on this topic and I think the new SDXC (notable for having up to 2TB capacity) format and the SxS should be added. SxS, or a similar card that plugs directly into the ExpressCard slot, will do well in the format wars I think. Benced (talk) 04:54, 9 September 2009 (UTC)

Where do they sell those 32,768.00 Gigabyte SD cards? I want one

I have a hunch that the Gibibyte article got some numbers wrong.

Now, the tables using GiB, GB, MiB and MB are a mess. Stick to one common units for the common information, technical units for the technical information, but don't mix the two. Moreover, on the technical table capacity is given in MiBs but transfer speed in MB/s, which is a consumer unit, different to the MiB and misleading. Can someone of the technical minded people correct the numbers and units please?

Don't use GiB units when dealing with consumer relevant details (the 'Common Information' table), or make a separate column detailing the current available capacities in GB and then GiB. Better yet, make a separate paragraph explaining the difference between the two terms with a link to the main article. Keep the two numbers separate. 77.49.88.107 (talk) 10:22, 24 November 2009 (UTC)

PC Card/JEIDA

Why aren't PC Card/PCMCIA/CardBus/JEIDA memory cards not dealt with here? 70.29.211.9 (talk) 12:31, 26 December 2009 (UTC)

Probably because they're old and obsolete. There should be a separate article for obsolete memory card types. SmartMedia could be moved there since it's been a dead format for several years. Keep this one just for what's currently in production or compatible with what's currently in production. Bizzybody (talk) 05:58, 19 October 2010 (UTC)

Since this is a comparison article, there is nothing wrong with providing the comparison here. The card can easily be flagged as an obsolete format. 86.176.152.185 (talk) 17:00, 11 February 2011 (UTC)

links

link 4: confused with other link link 43: dead (404) Galanom (talk) 22:20, 28 January 2010 (UTC)

256 meg SmartMedia

Shortly before SmartMedia took a HD-DVD type dive, the format was expanded to be capable of 256 meg. Some devices with controllers capable of 256 meg got firmware updates for that capacity, but the cards never showed up, aside from a very small number that command crazy high prices (or used to) if they ever come up for sale. There are adapter cards to use 128 meg or smaller XD cards in devices that use SmartMedia, but the XD socket is bulky and the adapters cannot be used with devices which require a memory card cover/door to be closed in order to function. I've no idea if those adapters will allow a 256 meg XD to be used in a SM device capable of addressing 256 meg SM cards. Bizzybody (talk) 06:04, 19 October 2010 (UTC)

Max capacity of SDHC cards.

The table shows the maximum capacity of the SDHC card as 64GB. The specification states that the max. size is 32GB. Although googling 'SDHC 64GB' turns up over 2 million hits, in reality none of the pages that I looked at (including those from the most reputable memory card suppliers) actually lists a 64MB SDHC card. The large number of hits presumably comes about because 64GB (in the SDXC variant) is listed on the same page as SDHC cards up to 32GB (Google lists pages where both search terms occur anywhere on the page, followed by pages where any (but not all) the search terms appear). I have tagged the claim in the article, and unless a valid citation is provided for the existence of real 64GB SDHC cards, I shall change the claim to read '32GB'. 86.176.152.185 (talk) 16:58, 11 February 2011 (UTC)

IOPS for memory cards

Where can one find typical IOPS (IO Operations per Second) for various kinds of memory cards?-96.233.30.57 (talk) 08:47, 8 May 2011 (UTC)

Article for obsolete and obscure removable memory?

There's one I recall that was as thin as Smart Media but only about 1/2" wide by about 1.5" long. The cards had only 4 or 6 contacts and one clipped corner at the contact end. The only time I encountered it was a couple of two megabyte cards with a cheap digital camera someone was using to take photos for a website. Bizzybody (talk) 09:47, 19 January 2012 (UTC)

USB 3.0 is 9 pins

In the table in Technical details, all USB versions are grouped together as 4 pin connections. This is incorrect for USB 3.0.

USB 3.0 is 9 pins, and is backwards compatible with 2.0 (4 pins). The plug looks almost identical on the host side (A-connector) with the extra 5 pins tucked into the rear of the connector. (thus the confusion that it is the same pin count as 2.0); it is twice as wide on the client side (Micro B connector).

See the USB 3.0 Wikipedia page. — Preceding unsigned comment added by Michael Stangeland (talk • contribs) 02:05, 26 March 2014 (UTC)

Stop serving 'mobile' versions, perlease!

Please can you stop serving the effing mobile version of Wikipedia to devices like tablets. You only started doing this very recently and unless you can get your script kiddies to understand that most tablets and smartphones have as good resolution as desktop / laptop screens, or better, and don't need that pxy designed-for-ancient-feature-phone mobile version you risk losing many users. I've just about had it up to my eyeballs with scrolling to the bottom of the screen on an iPad to request the 'desktop' version.

Anyone who sees this, editor or user, please get the message back to whoever performed this recent wrecking action on Wikipedia. Thank you.

Keep Wikipedia usable. — Preceding unsigned comment added by 86.130.102.148 (talk) 08:32, 14 July 2014 (UTC)

Why are you complaining here about it, seriously? Very few people see this talk section. • Sbmeirow • Talk • 14:02, 14 July 2014 (UTC)

Read-only column

Thanks to whoever wrote this, it's an awesome resource. Anecdotally, I think having a column that displays whether the card has a read-only toggle would be useful. I don't know enough about the subject, and I don't own any SD cards at the moment, so I can't do it myself. Exercisephys (talk) 00:59, 21 July 2014 (UTC)

It's already in there... --Matthiaspaul (talk) 08:56, 21 July 2014 (UTC)

SDHC max capacity (again)

This was discussed in 2011 (link) and ended up with two sources being added that supposedly validate the existence of 64GiB SDHC cards, despite the fact that SDHC states the maximum possible is 32GiB. These are:

• http://www.amazon.com/s/ref=nb_sb_noss?url=node%3D516866&field-keywords=micro+sd+card&rh=n%3A172282%2Cn%3A541966%2Cn%3A172456%2Cn%3A516866%2Ck%3Amicro+sd+card
• http://www.sandisk.com/products/memory-cards/microsd/extreme-uhs-i/?capacity=64GB

Frankly, these sources are a disgrace and should not even be considered for a claim that contradicts information included elsewhere. The first links to a product search page on Amazon which admittedly includes results for products described as being "64GB" (whether this is a base-2 or base-10 'giga' is unclear in context, so I'd assume the latter) and indeed "128GB" "SDHC" cards, but (1) it is a primary source and is therefore not considered good practice (WP:PRIMARY) and (2) as these cards seem to universally be unbranded it is plausible that they have simply been mislabelled by their manufacturers or vendors. The second link is a description of features of a manufacturers range of cards that include both SDHC and SDXC, therefore it is not clear what claims pertain to SDHC cards and what to SDXC.

Secondly, there is a claim in the table of a "theoretical maximum" storage capacity of 2 TiB for SDHC cards. This seems to me to be based entirely on original research; there is no source given, and as the specification apparently states that 32GiB is the maximum size of an SDHC, any larger card is non-conformant to the specification and is therefore (at least in some sense) not an SDHC card at all, so therefore it isn't theoretically possible to have a 2TiB SDHC card. Or do I misunderstand something? JulesH (talk) 21:02, 1 October 2014 (UTC)

I have removed the 64GB claims, as I am almost certain they're wrong. If somebody can find a non-primary reliable source that describes 64GB SDHC cards as available, please revert my changes, but I cannot see any. I haven't changed the 2TiB theoretical maximum, as I'm not 100% sure I'm right there. JulesH (talk) 21:14, 1 October 2014 (UTC)

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PS Vita Memory Card

Hi everyone, I just added information related to PS Vita Memory Card. It's the kind of memory card that works and only works on a Playstation Vita handheld. Despite its look-a-like dimensions and specification to Memory Stick Micro (M2), it's completely proprietary. I added this card to the registry for future reference. You are more than welcome to review my edits, and if you have any question, please feel free to add to comments. --Bill Gong 01:36, 27 June 2018 (UTC) — Preceding unsigned comment added by Xmagic5589 (talk • contribs)

Speed Classes

Where is the information on a comparison of speed classes? --KitchM (talk) 19:01, 4 March 2019 (UTC)