What makes a SD card secure?

[famousdavis]

Since buying my first PPC last May, I've occasionally wondered why Secure Digital memory cards are called that. What makes a SD card "secure" over any other memory card, like CompactFlash?

[Janak Parekh]

The original intention was that the music industry (and others) would develop the SDMI (Secure Digital Music Initiative) and use it with SD cards. To the best of my knowledge, nothing finalized has come out of the SDMI consortium (http://www.sdmi.org/) -- and I'm personally glad that's the case. :D

--janak

[famousdavis]

Janak, I had to wait all of 3 minutes to receive your thorough and informative reply -- this, in spite of my recent razzing.

Are you trying to make me ashamed of myself?

Well, it's not....it's not...it's...

Ah, shoot....

:oops:

:wink:

[Janak Parekh]

Are you trying to make me ashamed of myself?
Well, you're the one going offtopic on this thread too. :razzing:

Anyway, back ontopic: it's a shame flash memory's monikers are confusing. You're asking what the heck "Secure Digital" means... imagine an average consumer trying to grok "Secure Digital Slot" on the packaging of a PDA. It would make more sense if companies put a little effort into making things more sensible for consumers, driving down support costs, wouldn't it?

--janak

[famousdavis]

I think my 1910 PPC allows use of either a SD card or a MultiMedia card. Costco sold SDs -- not MMs, or if they did, I didn't see them on the shelf -- so I just bought a SD card. I have in my mind that MM cards are in some way or other inferior to SD cards, but I haven't a clue as to what real differences there are between the two. It doesn't really matter, as my 2 SD cards work.

You're right, the many various memory types are confusing to grapple with. I remember seeing a Front Page article on yet another new type of memory card manufacturers are pushing.

What I thought would be nice is if an SD card protected the contents through some type of encryption scheme. So, if I lost my SD card, you wouldn't be able to read its contents if you happened by, found it, and stuck it in your PPC. That, to me, is the obvious sense of a "Secure Digital" card.

[PetiteFlower]

As far as I know there's no real difference between SD and MMC other then MMCs don't come in large sizes right now.

[buckyg]

It seems like manufacturers weren't really trying to convince consumers they're stuff was secure when they branded SD cards "Secure", but rather trying to convince other businesses (software companies, content providers, etc.) that the ability is there to make what they put on the card secure.

That's the way I read it when I read specs anymore now that tell me something's "secure" or able to handle stuff like DRM protection, etc. It's a shame too, I like famousdavis' idea of making what I put on the card secure.

[dlangton]

As far as I know there's no real difference between SD and MMC other then MMCs don't come in large sizes right now

How big is large? Newegg has a 256MB MMC card available right now. There are 512MB multimedia cards on Ebay.

[Sven Johannsen]

Another difference is that MMC is an open standard and SD is a liscensed standard, property of SanDisk. So no matter who you buy an SD card from SanDisk makes a bit, which irks me, but I don't loose sleep over it.

[PetiteFlower]

I thought MM cards weren't available bigger then 128M yet.

[dlangton]

I thought MM cards weren't available bigger then 128M yet

They are available. Check http://www.newegg.com/app/ViewProductDesc.asp?description=20-155-250&catalog=68&depa=1 as an example. I'm thinking purchasing one myself.

[maikii]

What I thought would be nice is if an SD card protected the contents through some type of encryption scheme. So, if I lost my SD card, you wouldn't be able to read its contents if you happened by, found it, and stuck it in your PPC. That, to me, is the obvious sense of a "Secure Digital" card.4

Well, if that SD card would only work on your PPC, then you couldn't put it in your PC to transfer files from the PPC, and couldn't use it in your camera.

If you want encryption, however, Resco File Explorer for PPC has encryption, so that you can encrypt any files on your PPC, including I assume, those on the SD card. I have this File Explorer and recommend it highly, much better than the one that comes with the PPC OS. Good investment for $20. I haven't tried the encryption, however.

Anyhow, if your SD card (only) was encrypted, and you lost your PPC, what good would it do for only the files on the SD card to be encrypted? The finder could still read the other files on your PPC. Well, SD cards do have the unfortunate tendency to pop out sometimes, so I guess it's possible to lose the SD card only. In fact, it happened to me, I lost one that way, I have no idea where it popped out. I don't recall if there was any sensitive info on it, I hope not. Quite likely it blew away somewhere, and no one found it who knew what it was.

[Howard2k]

Good (non-Scamdisk) SD Cards are considerably faster than MMC cards.

[billbuckner]

Good (non-Scamdisk) SD Cards are considerably faster than MMC cards.
So I'm okay with a PNY SD card?

[whatsnext?]

the only difference(not really) between mmc's and sd's are that sd's have a little thing on the side to lock them :lol: :lol: :lol:

[maikii]

the only difference(not really) between mmc's and sd's are that sd's have a little thing on the side to lock them :lol: :lol: :lol:

Are you saying that you can use a MMC card in a slot that is designated as an SD slot? No problems with that? If so, how do MMC cards compare in price per MB?

[whatsnext?]

uhm... well... from what i have heard the are cheaper $ per mb.... and i think that they work in sd slots......

(If i am wrong dont shoot me please :snipersmile: :2gunfire: )

[Jon Westfall]

Gee, I always assumed that they were Secure Digital because of their expert data protection (i.e. sliding lock switch!) - I could feel free to give a person a file via SD Card and as long as I had locked it, they wouldn't be able to delete it off the card!

Now let me talk a little about how Windows 95's user accounts really helped secure that operating system...

The Moral of the Story: Things that sound like they create security in one form or another, rarely do. (I mean, a firewall sounds like its going to set your office ablaze doesn't it?)

[maikii]

[quote="dadarkmcse"]Gee, I always assumed that they were Secure Digital because of their expert data protection (i.e. sliding lock switch!) - I could feel free to give a person a file via SD Card and as long as I had locked it, they wouldn't be able to delete it off the card!
quote]

Well, it's possible that the write protection switch is the reason for the name. Now, how likely is it though, that you would give a person an SD card? Even if a trustworthy person, and you asked them to return the card, it could easily get lost, etc. I don't think SD cards will replace floppies and CDs for exchanging data between people!

One of my SD cards (Sandisk 256 MB) went bad via that switch. It got locked in the locked position (although I hadn't moved the switch, not intentionally, at least). I could still read the card, but couldn't write to it any more. (Sandisk sent me a replacement.)

I'd just as well not have that write-protect switch. If that were the only difference between SD and MMC, and the latter is not worse in other respects, and cheaper per megabytes, I would use MMC cards in the future, in the SD card slots. But I'm not sure that's the case, as I have just read a few people here say they think that is so. Anyone here actually used MMC cards in SD slots.

If it's true, Matsu****a (Panasonic) sure won't want that info to get out, as they get a percentage of each SD card sold.

Anyone here actually used the write-protect switch? For what purpose?

[gwinter]

The differences as far as I know:

1. SD card is physically thicker than MMC (a couple of mm I think).
2. Write-protect switch on SD card.
3. Maximum 4-bit interface on SD vs 1-bit on MMC.
4. For the same capacity, MMC has more usable space because on SD card, a portion is reserved for the "Secure" functionality.
5. There is licensing involved for SD standard as was mentioned.

SD slot should be backward compatible with MMC. The write-protect switch works just like the write-protect tab on floppy disk.