Sony Memory Stick technology and background

Sony are the only consumer goods manufacturer to have stuck with their own proprietary removable memory card. Their Memory Stick brand, introduced in 1998, actually covers a variety of different formats that have evolved as devices have changed, getting physically smaller but demanding more storage capacity. As with other memory card formats, the cards are made with solid state memory that retains the data once it’s removed from a device, so is used to backup data or transfer it to a PC. The term Memory Stick (MS) is a Sony trade mark for their memory cards and should not be confused with USB memory keys, or thumb sticks. They are often referred to as memory sticks but this is a generic term. Sony introduced their own format as a way of tying customers into their products, and are able to do this because they are strong in a breadth of consumer product markets where a method of transferring information such as pictures, videos, music and general computer files is required. MS cards are used directly in digital cameras, camcorders, mp3 players, Playstation game consoles and Sony Ericsson mobile phones. To enable the contents to be read by PCs, USB card readers can be used, or adapters that allow a Memory Stick to mimic another memory card format. These adapters for Memory Stick to PC Card or (CF) conversion are more expensive than those required for some other card formats as they need a controller chip to facilitate the translation. The table below gives a quick reference to the essentials of the different formats that have evolved. The original format...

MultiMediaCard (MMC) – SanDisk and Siemens NAND memory card for phones and smaller devices

Ten years after releasing the CompactFlash card and watching it become very successful, SanDisk had a go at repeating the trick, this time in collaboration with German company Siemens, releasing the MultiMediaCard (MMC). This was designed to take over from CompactFlash in most markets but also reach newer, smaller devices that the CF format is simply too big to fit, such as mobile phones, smartphones and PDAs. An MMC card is about the size of a postage stamp whereas a CF card is closer to a book of matches. One disadvantage of the form factor is that it is possible to insert an MMC card into a card reader slot the wrong way round. As the pins won’t connect there won’t be any damage, but it can be frustrating. The size reduction was made possible by the adoption of NAND flash memory developed by Toshiba and introduced in their SmartMedia card format in 1995. NAND flash memory allows greater storage densities, is cheaper to make and the data states are retained for longer than NOR flash memory, the method used by CF. NAND flash memory also has to be written to and erased in block mode, rather than bit-by-bit. This property is a disadvantage for directly accessing memory, as you do with a PC’s RAM, but makes it a good match for emulating secondary storage such as hard disks or optical disks. MMC came on the market in 1997 and the available memory sizes have constantly increased since then, although not to the same extent as cards that are available in CF form. There is a theoretical limit of...

Guide to SanDisk’s CompactFlash memory card

Memory manufacturer SanDisk introduced CompactFlash (CF) in 1994 as a small format memory card, which used the existing PCMCIA-ATA specification to communicate with PCs. These cards are roughly a quarter the size of a PC Card and use flash technology that allows data to be stored indefinitely, without any power to the card. CF cards come in two sizes, Type I and Type II. The only difference between the types is the thickness of the cards, 3.3mm for Type I and 5mm for Type II. This reflects the fact that there were different thickness PC Cards and slots at the time, and this allowed CF cards to take advantage of the thicker Type II PC Card slots. However, these thicker versions are now obsolete. CF had been devised primarily for devices smaller than PCs such as digital cameras and PDAs, and other memory manufacturers were attracted to the format by the standard interface. As CF slots began appearing on cameras and PDAs, as well as other more specialized devices, prices came down. At the same time, the available RAM on the cards increased until cards of 32Gb and more became available. The CF standard allows for a theoretical maximum size of 137Gb. The CF specifications are regularly being updated to take account of increased hard disk sizes, memory access speeds and upgrades to hard disk specifications such as IDE Ultra DMA 133 and SATA Because all types of CF cards can operate at both 3.3 and 5V, and they conform to the PCMCIA-ATA and TrueIDE functionality (compatible with ATA/ATAPI-4 disk interface specs) they can use almost any PC operating...

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