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...

xD Picture Card , the Fuji and Olympus memory card

The full title of the xD card, the xD-Picture Card, gives away its target market, it being squarely aimed at the digital camera market. And if that wasn\’t enough, the fact that it was developed by Fuji and Olympus, two camera firms, gives the game away completely. The xD card is designed to store pictures for safekeeping and to transfer them quickly and easily to a PC or photo-development system (such as an in-store kiosk). Announced in 2002 the format was intended to take over from SmartMedia cards, which had done an excellent job, but had an in-built 128MB size limit and were physically too large for the smaller cameras beginning to emerge at the beginning of the century. The format was based very closely on that of SmartMedia cards, being just an enclosure around a NAND flash memory chip with an interface very close to that of the chip\’s own pinouts, in the same way that SmartMedia had. This kept manufacture simple and cheap, there being no need for a separate controller as in some other formats, such as Secure Digital SD. From a marketing point of view, xD has not really delivered in the way that Fuji and Olympus hoped it would. CompactFlash, the venerable format that is a similar size to SmartMedia, has kept its position as the card of choice for high-end professional cameras. This is because camera size in that market segment is such that the larger physical size of the card isn�t a problem, and the bigger capacities that CF offers make a big difference to professional photographers. At the same time, SecureDigital...

Guide to SmartMedia cards, introduced as Solid State Floppy Disk Cards (SSFDC)

The SmartMedia memory card format was one of the earliest, introduced by Toshiba in 1995, when it was referred to as the Solid State Floppy Disk Card (SSFDC). It was launched shortly after the CompactFlash (CF) and of much the same size but a lot thinner, at 0.76mm rather than the 3.3mm of Type I CF cards. The other main competitors at the time were full size PC Card (PCMCIA) memory cards and the MiniCard format, which disappeared even faster than SmartMedia. One previously unique feature of the SmartMedia format that made it into the xD card format, was the imprint of a unique ID in each card along with an encryption key, allowing software to identify each card and act accordingly. This conformed to the Secure Digital Music Interface (SDMI) standard and was intended to act as a copy-protection mechanism at the application level, particularly for downloaded music, but only found very limited use, particularly since the SDMI initiative failed and folded in 2001. As with CompactFlash, the target market for SmartMedia was in the emerging portable devices that all had to store digital data and transfer it to PCs to be manipulated, or simply for safekeeping. PDAs and digital cameras were the two most frequently used devices but early navigation devices and early digital voice recorders also used the format. In order to transfer data to a PC the card can be inserted into a USB-enabled card reader or a PC Card-based adapter. Although the SmartMedia format is now considered obsolete and no dedicated card readers are available, many multi-format card readers will accept SmartMedia cards (but...

Secure Digital (SD) Cards – popular digital camera memory card format

Secure Digital (SD) is a memory card format used to transfer data between PCs and smaller devices, such as digital cameras, PDAs, MP3 players and mobile phones. Because the memory used is solid state, i.e. it remembers what’s been written to it when the power is removed, the information stays on the card when it’s unplugged. In order to get the data onto a PC, a card reader, either integrated into the PC or connected via a USB port, is required. Laptop users can also use an adapter that takes SD cards and fits into a PC Card slot. A consortium of Matsushita (aka Panasonic), Toshiba and SanDisk developed SD because they had been outflanked by Sony’s introduction of Memory Stick, their own proprietary card format, in 1998. This had two features that neither MultiMediaCard (MMC) nor CompactFlash, (CF) the other major player in memory cards at the time, possessed: a write-protect switch and integrated copyright protection. SD came onto the market in 1999 and was based, at least physically, on the MMC format. SD cards are slightly thicker but this allows the contacts to be recessed to protect them from damage. The other major physical change from the MMC design was an asymmetrical profile, which prevents SD cards from being inserted the wrong way round. The closeness of the two designs means that MMC cards can be used in SD slots, but not the other way round. Multi-function card readers are available with a slot than can accept SD cards as well as MMC, SmartMedia, Memory Stick and xD-Picture Card. One interesting and innovative adaptation is SD Plus,...

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...

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