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Memory card

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File:Flash-Media-Cards.jpg
Four major types of memory cards (from left to right: CompactFlash, MemoryStick, Secure Digital, and xD.

A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and laptop computers, telephones, music players, video game consoles, and other electronics. They offer high re-recordability, power-free storage, small form factor, and rugged environmental specifications. There are also non-solid state memory cards that do not use flash memory, and there are different types of flash memory. They are sometimes called "mem-cards" by gamers and/or techies.

Flash cards have been suggested as a possible replacement for the floppy disk, although USB flash memory drives, which work on almost any computer with a USB port, have been filling this role instead.

There are many different types of memory cards and jobs they are used for. Some common places include in digital cameras, in game consoles, in cell phones, and in industrial applications. PC card (PCMCIA) were among first commercial memory card formats (type I cards) to come out in the 1990s, but are now only mainly used in industrial applications and for I/O jobs (using types I/II/III), as a connection standard for devices (such as a modem). Also in 1990s, a number of memory card formats smaller than PC Card came out, including CompactFlash, SmartMedia, and Miniature Card. In other areas, tiny embedded memory cards (SID) were used in cell phones, game consoles started using proprietary memory card formats, and devices like PDAs and digital music players started using removable memory cards.

From the late 1990s into the early 2000s a host of new formats appeared, including SD/MMC, Memory Stick, xD-Picture Card, and a number of variants and smaller cards. The desire for ultra-small cards for cell-phones, PDAs, and compact digital cameras drove a trend toward smaller cards that left the previous generation of "compact" cards looking big. In digital cameras SmartMedia and CompactFlash had been very successful, in 2001 SM alone captured 50% of the digital camera market and CF had a strangle hold on professional digital cameras. By 2005 however, SD/MMC had nearly taken over SmartMedia's spot, though not to the same level and with stiff competition coming from Memory Stick variants, xD, as well as CompactFlash. In industrial fields, even the venerable PC card (PCMCIA) memory cards still manage to maintain a niche, while in cell-phones and PDAs, the memory card market is highly fragmented.

Nowadays, most new PCs have built-in slots for a variety of memory cards; Memory Stick, CompactFlash, SD, etc. Some digital gadgets support more than one memory card to ensure compatibility.

Data table of selected memory card formats

Name Acronym Form factor DRM
PC Card PCMCIA 85.6 × 54 × 3.3 mm None
CompactFlash I CF-I 43 × 36 × 3.3 mm None
CompactFlash II CF-II 43 × 36 × 5.5 mm None
SmartMedia SM / SMC 45 × 37 × 0.76 mm None
Memory Stick MS 50.0 × 21.5 × 2.8 mm MagicGate
Memory Stick Duo MSD 31.0 × 20.0 × 1.6 mm MagicGate
Memory Stick Micro M2 M2 15.0 × 12.5 × 1.2 mm MagicGate
Multimedia Card MMC 32 × 24 × 1.5 mm None
Reduced Size Multimedia Card RS-MMC 16 × 24 × 1.5 mm None
MMCmicro Card MMCmicro 12 × 14 × 1.1 mm None
Secure Digital Card SD 32 × 24 × 2.1 mm CPRM
miniSD Card miniSD 21.5 × 20 × 1.4 mm CPRM
microSD Card microSD 11 × 15 × 1 mm CPRM
xD-Picture Card xD 20 × 25 × 1.7 mm None
Intelligent Stick iStick 24 x 18 x 2.8 mm None
µ card µcard 32 x 24 x 1 mm Unknown

Since many EEPROM devices only allow a finite number of write cycles, some of these cards incorporate wear levelling algorithms to spread the wear and to avoid wearing out specific places which are often written to.

Overview of all memory card types

Main article: Comparison of memory cards
Memory cards physical sizes keep shrinking down while their respective logical size increases. (Compact flash 32MB, SD 128MB, miniSD 1.0GB, microSD 1.0GB
  • PCMCIA ATA Type I Flash Memory Card (PC Card ATA Type I) (max 8 GB flash as of 2005)
    • PCMCIA Linear Flash Cards, SRAM cards, etc.
    • PCMCIA Type II, Type III cards
  • CompactFlash® Card (Type I), CompactFlash High-Speed
  • CompactFlash® Type II, CF+(CF2.0), CF3.0
  • MiniCard™ (Miniature Card) (max 64 MB)
  • SmartMedia™ Card (SSFDC) (max 128 MB) (3.3 V,5 V)
  • xD-Picture Card™, xD-Picture Card Type M
  • Memory Stick, Magic Gate Memory Stick (max 128 MB); Memory Stick Select, MagicGate Memory Stick Select (
    • SecureMMC™
  • Secure Digital (SD™ Card), Secure Digital High-Speed, Secure Digital Plus/Xtra/etc (SD with USB connector)
    • miniSD™ Card
    • microSD™ Card (aka Transflash, T-Flash)
  • MU-Flash (Mu-Card) (Mu-Card Alliance of OMIA)
  • C-Flash™
  • SIM card (Subscriber Identity Module)
  • Smart card (ISO 7810 Card Standard , ISO 7816 Card Standard, etc.)
  • UFC (USB FlashCard) [1] (uses USB)
  • FISH Universal Transportable Memory Card Standard (uses USB)
  • Disk memory cards:
  • Intelligent Stick (iStick, a USB-based flash memory card with MMS)

Memory cards in video game consoles

Many video game consoles have used proprietary solid state memory cards to store data, especially since games started being distributed in read-only optical discs. The sizes in parenthesis are those of the official cards.

See also

Wikimedia Commons has media related to Memory card.
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