Welcome » IT Booklets » Operations » Appendix B: Glossary
D E F H I L M N O P R S T V W
DDASD - Direct access storage device. A magnetic disk storage device historically used in mainframe environments. DASD may also include hard drives used in personal computers. DSL - Digital subscriber line. A technology that uses existing copper telephone lines and advanced modulation schemes to provide high-speed telecommunications to businesses and homes. EEncryption - A data security technique used to protect information from unauthorized inspection or alteration. Information is encoded so that data appears as a meaningless string of letters and symbols during delivery or transmission. Upon receipt, the information is decoded using an encryption key.Enterprise Architecture - The configuration of computer systems within an organization. Includes local area networks (LANs), wide area networks (WANs), bridges, applications, etc.FFibre Channel - A high performance serial link supporting its own, as well as higher-level protocols such as the small computer system interface, high performance parallel interface framing protocol and intelligent peripheral interface. The Fibre Channel standard addresses the need for very fast transfers of large amounts of information. The fast (up to 1 Giga byte per second) technology can be converted for LAN technology by adding a switch specified in the Fibre Channel standard that handles multipoint addressing. Fibre Channel gives users one port that supports both channel and network interfaces, unburdening the computers from large number of input and output (I/O) ports. Fibre Channel provides control and complete error checking over the link. Frame Relay - A high-performance WAN protocol that operates at the physical and data link layers of the Open Systems Interconnect (OSI) reference model. Frame Relay is an example of a packet-switched technology. Packet-switched networks enable end stations to dynamically share the network medium and the available bandwidth. Frame relay uses existing T-1 and T-3 lines and provides connection speeds from 56 Kbps to T-1.HHBA - Host bus adapter. A host bus adapter provides I/O processing and physical connectivity between a server and storage. As the only part of a storage area network that resides in a server, HBAs also provide a critical link between the storage area network and the operating system and application software. Hub - Simple devices that pass all data traffic in both directions between the LAN sections they link. Hubs forward every message they receive to the other sections of the LAN, even those that do not need to go there. HVAC - Heating, ventilation, and air conditioning.II/O - Input/output.iSCSI - Internet small computer system interface. An Internet protocol based storage networking standard for linking data storage facilities, used to facilitate. iSCSI is data transfers over intranets and to manage storage over long distances.ISDN - Integrated systems digital networking. A hierarchy of digital switching and transmission systems that provides voice, data, and image in a unified manner. ISDN is synchronized so that all digital elements communicate in the same protocol at the same speed.LLAR - Legal amount recognition. The handwritten dollar amount of the check.MMainframe - An industry term for a large computer, typically used for the commercial applications of businesses and other large-scale computing purposes. Generally, a mainframe is associated with centralized rather than distributed computing. Media - Physical objects that store data, such as paper, hard disk drives, tapes, and compact disks (CDs).MICR - Magnetic ink character recognition. Magnetic codes found on the bottom of checks, deposit slips, and general ledger debit and credit tickets that allow a machine to scan (capture) the information. MICR encoding on a check includes the account number, the routing number, the serial number of the check and the amount of the check. The amount of the check is encoded when the proof department processes the check.Midrange - Computers that are more powerful and capable than personal computers but less powerful and capable than mainframe computers.MIPS - Millions of instructions per second. A general measure of computing performance and, by implication, the amount of work a larger computer can do.Mirroring - A process that copies data to multiple disks over a computer network in real time or close to real time. Mirroring reduces network traffic, ensures better availability of the website or files, or enables the site or downloaded files to arrive more quickly for users close to the mirror site.MIS - Management information systems. A general term for the computer systems in an enterprise that provide information about its business operations. NNAS - Network attached storage. Hard disk storage set up with its own network address rather than being attached to the department computer that is serving applications to a network's workstation users. By removing storage access and its management from the department server, both application programming and files can be served faster because they are not competing for the same processor resources. The network-attached storage device is attached to a local area network (typically, an Ethernet network) and assigned an IP address. File requests are mapped by the main server to the NAS file server.OOperating System - Programs that collectively manage application programs. Operating systems allocate system resources, provide access and security controls, maintain file systems, and manage communications between end users and hardware devices.PPBX - Private branch exchange. A telephone system within an enterprise that switches calls between enterprise users on local lines while allowing all users to share a certain number of external phone lines.Platform - The underlying computer system on which applications programs run. A platform consists of an operating system, the computer system's coordinating program, which in turn is built on the instruction set for a processor or microprocessor, and the hardware that performs logic operations and manages data movement in the computer. POD - Proof of deposit. The verification of the dollar amount written on a negotiable instrument being deposited. POTS - Plain old telephone system. Basic telephone service.RRAID - Redundant array of independent disks. The use of multiple hard disks to store the same data in different places. By placing data on multiple disks, I/O operations can overlap in a balanced way, improving performance. Since multiple disks increase the mean time between failures (MTBF), storing data redundantly also increases fault-tolerance. Recovery Site - An alternate location for processing information (and possibly conducting business) in an emergency. Usually distinguished as “hot” sites that are fully configured centers with compatible computer equipment and “cold” sites that are operational computer centers without the computer equipment.SSAN - Storage area network. A high-speed special-purpose network (or sub-network) that connects different types of data storage devices with associated data servers on behalf of a larger network of users. SAS 70 Report - An audit report of a servicing institution prepared in accordance with guidance provided in the American Institute of Certified Public Accountant's Statement of Auditing Standards Number 70.Scalability - A term that refers to how well a hardware and software system can adapt to increased demands. For example, a scalable network system would be one that can start with just a few nodes but can easily expand to thousands of nodes. Scalability can be a very important feature because it means the entity can invest in a system with confidence they will not quickly outgrow it. SCSI - Small computer systems interface (pronounced ”scuzzy”). A standard way of interfacing a computer to disk drives, tape drives, and other devices that require high-speed data transfer. Also, a secondary SAN protocol that allows computer applications to talk to storage devices.Server - A computer or other device that manages a network service. An example is a print server, which is a device that manages network printing.SLA - Service level agreement. SLAs detail the responsibilities of an IT service provider, the rights of the service provider’s customers, and the penalties assessed when the service provider violates any element of the SLA. SLAs also identify and define the service offering itself, plus the supported products, evaluation criteria, and quality of service customers should expect. SLAs are typically measured in terms of metrics. Examples include processing completion times and systems availability times.Storage Virtualization - The process of taking many different physical storage networks and devices, and making them appear as one “virtual” entity for purposes of management and administration.Switch - A device that connects more than two LAN segments that use the same data link and network protocol. TT-1 Line - A special type of telephone line for digital communication and transmission. T-1 lines provide for digital transmission with signaling speed of 1.544Mbps (1,544,000 bits per second). This is the standard for digital transmissions in North America. Usually delivered on fiber optic lines.TCO - Total cost of ownership. A term defining the true cost of ownership of a PC or other technology system. TCO includes:
- Original cost of the computer and software;
- Hardware and software upgrades;
- Technical support; and
- Training TCP/IP - Transmission control protocol/Internet protocol. A communication standard for transmitting data packets from one computer to another. TCP/IP is used on the Internet and other networks. The two parts of TCP/IP are TCP, which deals with constructions of data packets, and IP, which routes them from machine to machine. VVESDA - Very early smoke detection alert. A system that samples the air on a continuing basis and can detect fire at the pre-combustion stage.VOIP - Voice over Internet protocol. A term used in IP telephony for a set of facilities for managing the delivery of voice information using the Internet Protocol. WWorkstation - Any computer connected to a local-area network. WORM (Acronym) - Write once, read many times. A type of optical disk where a computer can save information once, can then read that information, but cannot change it.