Last year I bought a "universal" memory card reader. A month later Sony announced its Memory Stick Pro. All of a sudden my reader wasn't universal anymore. Pick a stick, any stick: Memory Stick, Memory Stick Select, Memory Stick Duo, MagicGate Memory Stick, or Memory Stick Pro Duo. Now tell me whether it works properly with the devices you own or want. Can't hear you....

As more and more devices support new forms of memory, figuring out what works with what has become a major irritation. SD mires you in a similar who's-on-first routine. A slot that isn't SDIO-enabled can't handle input/output devices such as SD cameras and Wi-Fi cards. But finding a slot's SDIO status requires you to bury yourself in spec sheets.

Confine yourself to memory, and you still need to distinguish among SD cards, the identical-looking MMC cards, and the new, even tinier Mini SD format. And SD cards 256MB and up come in different speeds. SanDisk calls its fast models "Extreme" and "Ultra II"; Panasonic's cards of the same capacities all use the fast design, without any indication. Exactly how are customers supposed to figure this out?

Determining the compatibility of media gets tricky the minute engineers improve the breed--which they usually do the day after you buy an example of it. Even with mature formats like CompactFlash and recordable DVD, you need a cheat sheet, and even then it's not always perfectly clear.

You'd think that finding information on media and compatible products would be easy. But media manufacturers' sites are surprisingly reticent about acknowledging and enumerating the differences; they often leave the worry to you. And so do device makers. Sony's very nice DSC-T1 camera can shoot 640 by 480 video at 30 frames per second--but only with Memory Stick Pro Duo. Kyocera's Finecam SL300R can shoot pictures at its best resolution 3.5 times per second--but only if you use high-speed SD media. What kind of card comes with each camera? A slow one that can't show off the device's advanced features.

You might expect that clicking Properties for a DVD or CD writer listed in Windows' Device Manager would give you a clue about its speed. Nope, and the drive itself won't either. But now that we've seen cases where fast media can damage a slower drive, it might make sense for new PCs to include a guide so that you're not left puzzling out the capabilities of your machine when it's two years old.

What we need is a standard nomenclature that clearly states at least three things about media: its capacity, its physical size, and its speed. Put the first in megabytes, the second in roman numerals (Size I, II, III), and the third in Arabic ones (1X, 2X, 3X). Devices like cameras could put a compatibility page in ROM. PCs could list such information in a standard file. Card readers could have the details on the base.

This scheme isn't perfect--we'd need categories to tell us whether digital rights management or I/O worked--but at least it would give users a fighting chance to avoid buying incompatible media or overpaying for fast media they don't need. Anything would be better than the chaos we have now.

Contributing Editor Stephen Manes has been writing about technology for two decades.