Compact Flash Drives
Open standard flash memory
A Compact Flash card comes in two different flavors: CF I, the standard Compact Flash card that has been around for over a decade; and CF II, its slightly wider cousin. Originally, this card was only a standard of flash memory, but today the basic format is used for various devices which can plug into the CF slot. As a flash memory [flash memory] standard, it's one of the oldest and today it's much larger than most of its competitors. It first came to prominence as memory for digital cameras and competed with all the early standards of flash memory from its generation, including MiniCard and SmartMedia.
Even though CF is more bulky than most modern formats of flash memory, it's still sometimes used for its original purpose. CF can be found in professional-grade digital cameras and any device that requires extremely large amounts of storage.
Since CF isn't just a method of flash memory anymore, it's able to push the storage limits for such a relatively small card. The CF format is really the definition of an interface that is similar to PCMCIA-ATA used in notebook computers. So, CF is actually a kind of computer slot for any device and flash memory storage is just one purpose for which the CF slot is actually a bit too big by today's standards. However, as a storage device, CF offers a lot of headroom in non-volatile memory.
Open- Source CF devices
Input / Output interface devices that use the CF specification are able to communicate with any gizmo that uses a CF slot. Some of these include:
- Ethernet cards
- Modems
- Wi-Fi adaptors
- Digital Cameras
- GPS receivers
- Barcode Readers
Non-volatile means that the data stored on the device is retained even when the power is shut off on the device. This is the common feature that defines all flash storage, including flash memory card formats and USB flash drives. Flash memory refers to solid-state mechanics of the electronically erasable programmable read only memory (EEPROM). An EEPROM is a kind of chip that works much like a hard drive except that it uses a solid state design, meaning it has no moving parts.
CF Microdrives are tiny hard drives built into a CF card. These tiny hard drives give significant gains to the amount of storage in a single flash memory card. SD microdrives can be scaled upwards of 12 Gigs. So, although they're bigger than many of the newest flash memory formats, CF is more than just flash memory, it's an open standard. Like Secure Digital (SD) as an open source standard, there are a multitude of devices being made that use the CF slot. SD uses a standard called SDIO, which allows third-party manufacturers to build peripheral devices that fit into an SDIO slot. CF is even more established because its interface is electronically identical to PCMCIA.
So, while most manufacturers are making flash memory devices to store more and more bits of data, the Compact Flash has morphed into a computer card. The Secure Digital card seems to have similar capabilities, but it not nearly as well established.