Hitachi 9960 manual Glossary, Synchronous, Tach, Veritas, Virtual Logical Volume Image Manager

Glossary

Synchronous

Synchronous communications occurs when the transmission of data between two devices is synchronized with a clocking scheme or other technique. The sender and receiver need to synchronize with one another before data is sent. In synchronous communication the bit stream and the clock pulse are synchronized by a special bit transition pattern in the digital signal creating an exactly timed stream of bits from the sending device to the receiving device. An example of such a mechanism is bipolar encoding. Synchronous communication is either character or bit oriented. Character oriented synchronous transmissions are used to send blocks of characters such as found in ASCII (American Standard Code for Information Interchange) files. Bit oriented synchronous communication is used primarily for the transmission of binary data.

See also Asynchronous, ASCII, Binary and EBCDIC, HRC, HORC.

Tach

Abbreviation for Tachyon Fibre Channel interface.

TB

A Terabyte (TB) equals 1000 Gigabytes. Some vendors today define a terabyte as 1024 GB, causing confusion in the industry.

TCP

Transmission Control Protocol or TCP is a transport layer component of the Internet’s TCP/IP protocol suite. It sits above IP in the protocol stack and provides reliable data delivery services over connection-oriented links. TCP uses IP to deliver information across a network and makes up for the deficiency of IP providing a guarantee of reliable delivery services that IP does not. TCP messages and data are encapsulated into IP datagrams and IP delivers them across the network.

VERITAS®

A Mountain View, California software company that develops and supports volume and file management software products for a variety of Unix® and Windows® platforms.

Virtual Logical Volume Image Manager

Virtual Logical Volume Image Manager (VLVI) is a software utility in the Resource Manager 7000/9000™ that allows for configuration of RAID configurations, create, delete, verify, rebuild, tune, and abort operations. See also RAID and the Freedom 9000 Resource Manager 7000/9000™.

Volume

An ESA/390® term for the information recorded on a single disk unit or recording medium. Indirectly, a volume can refer to the unit of recording medium itself. On a non-removable medium storage device such as a disk drive, the terms may also refer, indirectly, to the storage device that is associated with the volume. When a user stores multiple volumes on a single storage medium transparent to the program, the volumes are referred to as logical volumes.

69