A memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players and video game consoles. They are small, re-recordable, and able to retain data without power.
PC Cards (PCMCIA) were among first commercial memory card formats (type I cards) to come out in the 1990s, but are now mainly used in industrial applications and to connect I/O devices such as modems. In 1990s, a number of memory card formats smaller than PC Card arrived, including CompactFlash, SmartMedia, and Miniature Card. The desire for smaller cards for cell-phones, PDAs, and compact digital cameras drove a trend 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 stranglehold 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, as well as CompactFlash. In industrial fields, even the venerable PC card (PCMCIA) memory cards still manage to maintain a niche, while in mobile phones and PDAs, the memory card market was highly fragmented until 2010 when micro-SD came to dominate new high-end phones and tablet computers.
Since 2010, new products of Sony (previously only using Memory Stick) and Olympus (previously only using XD-Card) are offered with an additional SD-Card slot. Effectively the format war has turned in SD-Card's favor.
Data table of selected memory card formats 
|PC Card||PCMCIA||85.6 × 54 × 3.3 mm||No|
|CompactFlash I||CF-I||43 × 36 × 3.3 mm||No|
|CompactFlash II||CF-II||43 × 36 × 5.5 mm||No|
|SmartMedia||SM / SMC||45 × 37 × 0.76 mm||No|
|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 PRO Duo||MSPD||31.0 × 20.0 × 1.6 mm||MagicGate|
|Memory Stick PRO-HG Duo||MSPDX||31.0 × 20.0 × 1.6 mm||MagicGate|
|Memory Stick Micro M2||M2||15.0 × 12.5 × 1.2 mm||MagicGate|
|Miniature Card||37 × 45 × 3.5 mm||No|
|Multimedia Card||MMC||32 × 24 × 1.5 mm||No|
|Reduced Size Multimedia Card||RS-MMC||16 × 24 × 1.5 mm||No|
|MMCmicro Card||MMCmicro||12 × 14 × 1.1 mm||No|
|Secure Digital card||SD||32 × 24 × 2.1 mm||CPRM|
|Universal Flash Storage||UFS||Unknown|
|miniSD card||miniSD||21.5 × 20 × 1.4 mm||CPRM|
|microSD card||microSD||15 × 11 × 0.7 mm||CPRM|
|xD-Picture Card||xD||20 × 25 × 1.7 mm||No|
|Intelligent Stick||iStick||24 × 18 × 2.8 mm||No|
|Serial Flash Module||SFM||45 × 15 mm||No|
|µ card||µcard||32 × 24 × 1 mm||Unknown|
|NT Card||NT NT+||44 × 24 × 2.5 mm||No|
|XQD card||XQD||38.5 × 29.8 × 3.8 mm||Unknown|
Secure Digital card (SD)
MiniSD Card with an SD card adapter
xD-Picture Card (xD)
Overview of all memory card types 
- PCMCIA ATA Type I Flash Memory Card (PC Card ATA Type I)
- 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 (64 MiB))
- SmartMedia Card (SSFDC) (max 128 MB) (3.3 V,5 V)
- xD-Picture Card, xD-Picture Card Type M
- Memory Stick, MagicGate Memory Stick (max 128 MB); Memory Stick Select, MagicGate Memory Stick Select ("Select" means: 2x128 MB with A/B switch)
- Secure Digital (SD Card), Secure Digital High-Speed, Secure Digital Plus/Xtra/etc (SD with USB connector)
- MU-Flash (Mu-Card) (Mu-Card Alliance of OMIA)
- SIM card (Subscriber Identity Module)
- Smart card (ISO/IEC 7810, ISO/IEC 7816 card standards, etc.)
- UFC (USB FlashCard)  (uses USB)
- FISH Universal Transportable Memory Card Standard (uses USB)
- Intelligent Stick (iStick, a USB-based flash memory card with MMS)
- SxS (S-by-S) memory card, a new memory card specification developed by Sandisk and Sony. SxS complies to the ExpressCard industry standard. 
- Nexflash Winbond Serial Flash Module (SFM) cards, size range 1 mb, 2 mb and 4 mb.
Video game consoles 
|This section does not cite any references or sources. (December 2011)|
Video game consoles use memory cards to hold saved game data. Cartridge-based systems primarily used battery-backed volatile RAM within each individual cartridge to hold saves for that game. The Neo Geo AES, released in 1990 by SNK, was the first video game console able to use a memory card. AES memory cards were also compatible with Neo-Geo MVS arcade cabinets, allowing players to migrate saves between home and arcade systems and vice versa. Memory cards became commonplace when home consoles moved to read-only optical discs for storing the game program, beginning with systems such as the TurboGrafx-CD and Mega-CD.
Home consoles now commonly use hard disk drive storage for saved games and allow the use of generic USB flash drives or other card formats via a memory card reader to transport game saves and other game information, along with cloud storage saving, though most portable gaming systems still rely on custom memory cartridges to store program data, due to their low power consumption, smaller physical size and reduced mechanical complexity.
See also 
- Grunin, Lori (2010-01-06). "Sony does SD; Panasonic intros first SDXC cards | 2010 CES — CNET Blogs". Ces.cnet.com. Retrieved 2013-01-07.
- "Format-Krieg entschieden: SD-Card setzt sich durch" ("format-war resolved: SD-card prevails"), Chip-online, 14. January 2010
- "Camera trends come into focus for 2010", msnbc, 13. January.2010 "As much as the storage-format war cleared up a bit with Sony announcing that it would support SD and SDHC cards ..."
- "FEATURE: Playing Your Cards Right at Retail", Peter K. Burian, 4. June 2010. "Some industry observers have suggested that this development signals an end to the 'format war,' ..."
- "SanDisk and Sony announce SxS memory card: Digital Photography Review". Dpreview.com. Retrieved 2013-01-07.
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