Technical Corner > The PC Glossary - Definitions of Computer and Internet Terms

Computer Terms Beginning with "U"

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MysteRy:
Source : PC.net


U

U is the standard unit of measurement for rack-mounted equipment. Racks can be used to house servers, hard drives, switches, routers, and other computer hardware. They are also used for mounting audio and video equipment. Standard racks are 24 inches wide, but vary in height. For this reason, the U unit measures how tall a rack-mountable hardware device is.

1U is equal to 1.75 inches. Therefore, a 1U piece of equipment is 1.75 inches tall and takes up one unit of rack space. A 2U device is 3.5 inches tall and takes up 2 units of rack space. Racks themselves are also measured in U. For example, a 10U rack could store 10 1U devices or 5 2U devices. It could also store 3 3U devices, with just enough space left over for your miniature Star Wars action figure.

MysteRy:
UDDI

Stands for "Universal Description Discovery and Integration." UDDI is a protocol that allows businesses to promote, use, and share services over the Internet. It is an OASIS Standard, which is supported by several major technology companies. Members include Microsoft, Cisco, Oracle, Avaya, Sun Microsystems, and others.

The UDDI protocol serves as a foundational tool that allows businesses to find each other and complete transactions quickly and easily. Companies that use the UDDI protocol can extend their market reach and find new customers while also finding other businesses that offer useful services to them. Because UDDI uses a standard format for describing business services, it is easy to search and find useful services offered from other businesses.

MysteRy:
UDP

Stands for "User Datagram Protocol." It is part of the TCP/IP suite of protocols used for data transferring. UDP is a known as a "stateless" protocol, meaning it doesn't acknowledge that the packets being sent have been received. For this reason, the UDP protocol is typically used for streaming media. While you might see skips in video or hear some fuzz in audio clips, UDP transmission prevents the playback from stopping completely.

MysteRy:
Ultra DMA

This technology for transferring data between a computer's hard disk and memory was developed by Quantum and Intel. The maximum burst rate of an Ultra DMA hard drive is 33.3 MBps. The original DMA (Direct Memory Access) protocol could only transfer data at half that speed.

Thanks to Ultra DMA, programs can open faster and run more smoothly. This is because Utlra DMA can send more data to the memory in less time than the original DMA. Ultra DMA also has a built-in utility called Cyclical Redundancy Checking (CRC) that helps protect data integrity. So if you want a nice, fast hard drive, look for one that supports Ultra DMA.

MysteRy:
UML

Stands for "Unified Modeling Language." This is a programming language that is used for object-oriented software development. To organize program code more efficiently, programmers often create "objects" that are sets of structured data within programs. UML, which has been standardized by the Object Management Group (OMG), was designed for this purpose. The language has gained enough support that it has become a standard language for visualizing and constructing software programs.

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