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CF was the first flash memory standard, and was originally built around Intel's NOR-based flash memory. NOR-based flash has lower density than newer NAND-based systems, and Compact Flash is therefore (in spite of its name) larger than later standards like MMC, SD, or Memory Stick. CF memory cards are usually cheaper than cards of the same capacity conforming to those other standards.
CompactFlash defines a physical interface which is smaller than, but electrically identical to, the PCMCIA-ATA interface. That is, it appears to the host device as if it were a hard disk of some defined size. The connector is about 43 mm wide, and the case is 36mm deep and comes in two standard thicknesses, CF I (3.3 mm), and CF II (5 mm). Both types are otherwise identical. CF I cards can be used in CF II slots, but CF II cards are too thick to fit in CF I slots. Flash memory cards are usually CF I.
Flash memory devices are non-volatile and solid state, and thus are more robust than disk drives, and consume around 5% of the power required by small disk drives. They operate at 3.3 volts or 5 volts, and can be swapped from system to system. CF cards with flash memory are able to cope with extremely rapid changes in temperature. Industrial versions of flash memory cards can operate at a range of -45°C to +85°C.
CF devices are used in handheld and laptopA laptop computer (also known as notebook computer) is a small mobile personal computer, usually weighing around from 1 to 3 kilograms (2 to 7 pounds). Notebooks smaller than an A4 sheet of paper and weighing around 1 kg are sometimes called sub-notebooks computers (which may or may not take larger form-factor cards), digital cameraDigital cameras, as opposed to film or videotape ones, use an electronic sensor to record the (still or moving) image and sound, as a piece of electronic data. Nowadays, cameras are multifunctional and the same machine can take photos, video or sound.s, and a wide variety of other devices, including desktop computers.
As of 2004, CompactFlash cards are available in capacities from about 8 megabyteA megabyte is a unit of measurement for computer storage, memory and information; while its exact definition varies, it is in theory equal to one million bytes. The symbol for megabyte is MB (note B for Byte, lowercase b would mean bit). Three definitionss to about 8 gigabyteA gigabyte (symbol GB is a unit of measurement in computers of one thousand million bytes (the same as one billion bytes in the short scale usage). However, because computers work on the binary system, rather than a gigabyte being 103 Megabytes (1000 MBs)s. (Here, one megabyte is defined as 1 million bytes, and one gigabyte is defined as 1000 million bytes.)
Originally released in 1999 by IBMThis article is about the International Business Machines Corporation; see IBM (disambiguation) for other uses of this abbreviation. International Business Machines Corporation IBM or colloquially, Big Blue (incorporated June 15, 1911, in operation since in a 340 megabyte capacity, MicrodriveThe name Microdrive has been used to designate data storage devices. There are at least two (completely unrelated) devices bearing this name: A tape-loop storage system from the 1980s, used in Sinclair Research's ZX Spectrum and Sinclair QL home computerss are tiny hard disks that fit into the CF II format and are now ( 20042004 is a leap year starting on Thursday (the link is to a full 2004 calendar), and has also been designated the: International Year of Rice International Year to Commemorate the Struggle against Slavery and its Abolition Elections are to be held in 73 co) available in sizes up to 4 gigabytes.
These drives fit into any CF II slot; however, they take more power than flash memory and so may not work in some low-power devices (for example, NEC HPCs). Being a mechanical device they are more sensitive to physical shock and temperature changes than flash memory, though in practice they are very robust.