Hard drive formats include EIDE and ATA. Newer hard drives will also be advertised as being UDMA. This can be a little confusing for the person looking to buy a new hard drive, but in short, UDMA hard drives are EIDE and ATA. UDMA is not a type of hardware, although certain protocols might require a set number of pins on a hard drive cable, but instead a protocol that specifies how data are transferred from the hard drive to the motherboard.
What Does UDMA Stand For?
The acronym means Ultra Direct Memory Access. UDMA is a protocol instead of a piece of hardware. Firmware on newer motherboards allows a computer to use this protocol, which speeds up data access times.
UDMA-3 Transfer Rate
UDMA is a protocol that speeds up the transmission of data from the hard drive to the motherboard. The UDMA-3 protocol used by most UDMA drives allows for a data transfer rate of 33 megabits per second. The UDMA-3 protocol that was developed as an extension for EIDE/ATA hard drives requires a 40-pin cable.
Can a Motherboard without UDMA Support Use These Drives?
The connection for UDMA drives is a standard SATA/EIDE interface. For a user to take full advantage of a UDMA hard drive, the motherboard and the BIOS must support this protocol. Drives that support this data transfer protocol function as normal EIDE/ATA drives in older computers with standard EIDE/ATA connections.
Non-UDMA Data Transfer Rate
The data transfer rate for IDE/ATA hard drives before the introduction of the UDMA protocol was 16.6 megabytes per second. This means drives that support the newer technology are capable of transferring data twice as fast as their older, non-UDMA hard drives.
UDMA-4
UDMA-3 drivers required cables with 40 pins to achieve the transfer rate. In 1998, Intel and Quantum introduced an improvement to the UDMA protocol that allowed for a data transfer rate of 66 megabytes per second. The newer technology, dubbed UDMA-4, requires a pin with 80 cables, according to Tech Talk Reviews.
Software Requirements
In addition to the BIOS supporting UDMA hard drives, a user who wants to use a UDMA hard drive in his computer must be running an operating system capable of multitasking. Linux, Windows and Mac OS X allow this, and hard disk device drivers must be present before UDMA features of such a drive can be used.
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