PCMCIA hard drive cards provide high storage capacities for notebook and palmtop computers, personal digital assistants (PDAs), mobile systems, and PCMIA-equipped computers. They carry specifications for hard drive type, technology standard, form factor, performance, and power. PCMCIA hard drive cards take their name from the Personal Computer Memory Card Association (PCMCIA), the organization which develops and maintains standards for PCMCIA cards. Originally, these boards were known as PC cards because they were designed to add memory to portable computers. As PCMCIA standards and technologies evolved, however, PCMCIA cards were added to many types of devices.
PCMCIA hard drive cards may be designed for use with internal or external hard drives. Cards that are designed for use with internal hard drives remain inside the host computer when inserted. Cards that are designed for use with external hard drives do not. Related product specifications to consider when choosing PCMIA hard drive cards include card capacity and number of hard drive disks (HDD). The data transfer rate, the data buffer, and the average seek time are also important to consider. Typically, the data transfer rate is measured in MB/sec. The data buffer is a temporary storage area where data is saved before it is sent to the system. Average seek time is the average amount of time needed to move the drive heads from one cylinder to another cylinder.
PCMCIA hard drive cards can be categorized by form factor. Type I cards are 54 mm x 85.4 mm, and can be up to 3.3 mm thick. Type II cards are 54 mm x 85.4 mm, and can be up to 5.5 mm thick. Type III cards are 54 mm x 85.4 mm, and can be up to 10.5 mm thick. Type IV cards have not yet been ratified by the PCMCIA consortium; however, their size is expected to be 54 mm x 85.4 mm with a thickness of 18 mm. Other form factors for PCMCIA hard drive cards include SmartMedia Card, CompactFlash, Miniature Card, Solid State Floppy Disk (SSFDC), and MultiMediaCard (MMC).
There are several major technology standards for PCMCIA hard drive cards. PC Card Standard 95 is the PCMCIA’s original device standard. It has a 68-pin interface with 16 bits of address and data. CardBus technology runs at 33 MHz and is for cards with 32 bits of address and data. Miniature card technology products are about one-fourth the size of PC Card Standard 95. These PCMCIA hard drive cards use StrataFlash® (Numonyx B.V.) technology, a multilevel cellular architecture; and µBGA, a type of ball grid array. CompactFlash, SmartMedia, and CardBay cards are also available.