| UltraDMA
(UDMA) |
Ultra
DMA/66 (DMA = Direct Memory Access) is the successor of Ultra DMA/33. Ultra
DMA/66 doubles the bus transfer rate of Ultra DMA/33 to 66.6 MB/s (Ultra
DMA/33 = 33.3 MB/s). As with Ultra DMA/33, CRC (Cyclic Redundancy Check)
verifies the integrity of transferred data. |
| UltraSCSI |
This is
an old term for the FAST-20 data rate. This term was dropped by the ANSI
committee because the company UltraStore owned a trademark on the term Ultra
SCSI, so it could not be used by the standards committee to describe its
work. If you see this term anywhere, read carefully to see if it refers
to the UltraStore trademark (which refers to a SCSI FAST class of product)
or if the writer is incorrectly using this term for FAST-20. |
| Unformatted
Capacity |
The total
number of usable bytes on a disk, including the space that will be required
to later to record location, boundary definitions, and timing information.
(See formatted capacity for comparison.) |
| USB |
Short
for Universal Serial Bus, an external bus standard that supports data transfer
rates of 12 Mbps (12 million bits per second). A single USB port can be
used to connect up to 127 peripheral devices, such as mice, modems, and
keyboards. USB also supports Plug-and-Play installation and hot plugging. |
| USB
2.0 |
Universal
Serial Bus High Speed is the next generation of Universal Serial Bus and
is 40X faster than USB 1.1 with a transfer rate of 480 Mbps. USB 2.0 will
allow all sorts of new and improved USB devices to be added to the USB product
lineup such as fast disk drives, CDRW's, High Quality Video Cameras, and
High Speed Scanners. |
