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UAE
Unrecoverable Application Error. Occured often in Windows 3.0 and below. UAEs would bring the entire machine down causing loss of data.
Windows 3.1 greatly improved the handling of UAEs. While UAEs still occur (much less that previously), they crash only that application and not Windows or the entire machine.
UART
Universal Asynchronous Receiver - Transmitter, the chip that converts parallel data into serial asynchronous data.
UDP
User Datagram Protocol, the unreliable internet transport protocol.
Ultra SCSI
A standard for SCSI data transfers. It allows a transfer rate of up to 20 Mbytes/sec over an 8-bit SCSI bus and up to 40 Mbytes/sec over a 16-bit SCSI bus. STA (SCSI Trade Association) supports using the term "Ultra SCSI" over the term "Fast-20".
Ultra2 SCSI
A standard for SCSI data transfers. It allows a transfer rate of up to 80 MB/sec over a 16-bit SCSI bus. STA (SCSI Trade Association) supports using the term "Ultra2 SCSI" over the term "Fast-40"
UNIX
An operating system developed by AT&T in 1972; it features multiuser support, pre-emptive multitasking, and strong networking capabilities. Many versions of UNIX, and UNIX-like clones, have been produced through the years, including System V, BSD, NetBSD, Linux, AIX, A/UX, MINIX, SunOS, etc.
Upper Memory Area
On IBM PC and compatible computers. The 384K area of address space adjacent to the 640K of conventional memory (these two total 1 Megabyte). This area is usually reserved for running your system's hardware, such as your monitor, and is not considered part of total memory because applications cannot store information in this area. In 386 enhanced mode, Windows can access unused portions of this area. Some memory managers also allow applications access to unused portions of this area.
Upper Memory Blocks
On IBM PC and compatible computers. Areas of the upper memory area that contain general-purpose memory and that can be used to hold device drivers or other memory-resident programs in order to leave more conventional memory available for applications.
UPS
Uninterruptible Power Supply. A backup power unit that provides continuous power when the normal power supply is interrupted. UPS systems can be stand-by, only supplying power when the regular supply is interrupted, or fulltime, relying on regular power and/or batteries to supply it while it supplies power to the protected device. A UPS is not necessary on most computer systems, but can be important on systems that need to be up 24 hours a day, such as servers.
Utility
A program intended to make the use of a computer or of an application program easier.
UUCP
UNIX to UNIX Copy, a primitive UNIX data communication protocol.
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