Card Readers and Memory Cards 101

By Susan Baxter
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If you've spent any time shopping for a digital camera, video recorder, MP3 player, smartphone or other electronic device, you've probably run into some pretty technical information and industry lingo. Add in the mountain of extended memory cards for these devices – each with its own acronym – as well the jargon listed in card reader specifications out there and it can all get pretty overwhelming for the average consumer.

Choosing the best electronic device, memory card and card reader for you depends on your being able to absorb as much information as you can from reviews and specifications about the products. If you don't know what they do, or don't do, you won't know if they meet your needs. At TopTenREVIEWS We Do the Research So You Don't Have To.TM Here we present basic information about the most popular memory cards, as well as some terms you might come across while shopping the virtual electronics aisle online for card readers. In your virtual shopping trip, be sure to check out our card reader reviews as well.

Card Reader Lingo
USB 2.0: USB stands for Universal Serial Bus, the most common type of computer port. USB cables connect things like keyboards, mice, printers, game controls, thumb drives and digital cameras to your computer. USB 2.0 refers to high-speed USB ports and cables which support a theoretical maximum transfer rate of 480Mbps (megabits per second). Many USB 2.0 devices are compatible with USB 1.1 ports, which support transfer rates of only 12Mbps.

Hot-swappable and Hot-pluggable: Products touting this functionality are ones that allow you to connect and disconnect the device from your computer without having to turn it off or reboot.

Plug-and-play: This term means just what it sounds like. Plug-and-play devices don't require any additional software or drivers to function with your computer. You simply plug them in and they’ll play immediately.

Memory Stick (MS)
Because this type of memory was developed by Sony, most Sony products use Memory Stick cards (and other brands do not). The original Memory Stick and Memory Stick PRO are longer and wider than the more compact Memory Stick PRO Duo. The MS PRO Duo can fit in devices that use the original Memory Stick by using an adapter. The adapter is the same size as the original Memory Stick and allows the MS Duo to sit inside it.

The Memory Stick PRO-HG Duo is the same size as the MS PRO Duo but allows for higher storage capacities and faster transfer rates, making it ideal for capturing high-definition photos and video. The M2 is Sony's answer to the mini- and micro-sized cards for small devices such as digital music players and phones. You'll also see card readers that support MagicGate Memory Stick cards. MagicGate refers to an encryption technology developed by Sony that controls how files are copied or transferred in Memory Stick products.

Secure Digital (SD) and Secure Digital High Capacity (SDHC)
These are some of the most popular and best-selling memory cards on the market, and they are widely used in digital cameras, MP3 players, PDAs, phones and other electronic devices. SD and SDHC cards are identical in size; the difference is in the memory capacity of the cards. Standard SD cards offer 1GB-4GB of memory. SDHC takes if from there, with 4GB-32GB cards. SDXC (Secure Digital Extended Capacity) cards have capacities up to 32 terabytes (TB). Be aware that even though the cards are identical in size, the internal changes that allow for larger capacities may make SDHC and SDXC cards incompatible with electronic devices and card readers designed for standard SD cards.

CompactFlash (CF)
CompactFlash cards are physically the largest of the common memory card formats. CompactFlash Type I and Type II cards have the same length and height, but they have different widths. Type I is 3.3mm thick, while Type II is 5mm thick. Many card readers will read both types, but in some devices the slot is too small for Type II. The Extreme and Ultra CompactFlash cards have a higher memory capacity. The CF specification can support soaring capacities up to 128 petabytes (PB), but most cards on the market fall in the 2GB-64GB range.

Microdrives are the same size as CF Type I cards. However, they are not, strictly speaking, the same as other flash memory cards as they are mechanical and have tiny moving parts. They were originally designed, in part, to provide higher storage capacity. Essentially, they are mini, self-contained hard drives, and they often require more power when being read by a card reader.

MultiMediaCard (MMC)
MultiMediaCard memory cards are roughly the size of a postage stamp and are almost identical to SD and SDHC cards – so much so that they will fit in SD card slots and may even work with some devices that use SD cards, if the software on the device also supports MMC. (Though, we wouldn't recommend exchanging them willy-nilly. Always default to the recommendations of your devices' manufacturers.). Also like SD and SDHC, the MMC line offers mini- and micro-sized cards: the RS-MMC (Reduced Size) and the MMCmicro. MMCmobile and MMCplus cards support higher speeds than the original MMC cards. MultiMediaCards are available with storage capacities up to 32GB.

Extreme Digital Picture Card (xD)
Extreme Digital Picture Cards are smaller than SD and Memory Stick cards. Standard xD Picture Cards have up to 512MB of memory, while Types M, H and M+ have storage capacities up to 2GB. xD Picture Cards Types M, H and M+ also boast faster speeds for reading and writing data, with M+ being the fastest. xD Picture Cards are mainly used in Olympus and FujiFilm digital cameras. While cameras that require this card type are no longer manufactured, the memory card format is still manufactured and widely available.

SmartMedia (SM)
SmartMedia memory cards are no longer manufactured. They were originally marketed as a tiny replacement for 3.5 floppy disks, though that market never took off and they were used mainly in digital cameras and other devices. SM cards are similar in size to CompactFlash cards. Higher capacity SmartMedia cards were never released. The biggest SM card holds a mere 128MB of information. Many multi-card readers support this format, but not all.

Olympus DC
This memory card type was created specifically for use in Olympus and FujiFilm digital cameras. In 2002, the companies moved away from this card type in favor of their new creation, the Extreme Digital (xD) Picture Card, which would be more competitive with Sony's Memory Stick Duo in terms of both size and storage capacity. Olympic DC cards – and devices that use them – are no longer manufactured, and very few card readers support this card type. If you're using this type of memory card, the IOGEAR GFR281 does read it.

 

 
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