The Terminology of Systems Suppport

Prepared in conjunction with the panel Getting Systems Support: Speak Their Language or Do-It-Yourself, Monday, June 9th, 1997, Seattle

This brief glossary has been culled from a variety of sources, including Howard Besser and Jennifer Trant's Introduction to Imaging (1995), Printing Impressions (March 1997), a large contribution from Carolyn Edds, and Fortune Technology Buyer's Guide (Winter 1997).


algorithm:
A rule governing computer processes, often mathematical.

analog:
A continuously varying indicator representing changing values, as in an analog watch, which uses movable hour, minute and second hands.

application program/application software:
A program or software that performs a specific task, such as word processing or database management.

architecture:
The configuration of the hardware and software in a computer system.

ASCII:
American Standard Code for Information Interchange: A standard that defines which values are used for letters, numbers, and sym bls by using a 7-bit code and an 8th check bit.

backbone:
A network cabling segment that interconnects a group of network segments or systems. The backbone is often dedicated to server traffic or kept between wiring closets (housing MSAUs, concentrators, or hubs) so the systems can operate faster or over longer distances.

bandwidth:
The transmission capacity of a communications channel, usually expressed in bits or bytes per second (the former is also called baud rate).

bit:
The smallest unit of computerized information. In the computer's binary language this is the simple on and off code.

bit-mapped image:
An image created from a series of bits and bytes that form pixels. Each pixel can vary in color or gray-scale value. Also known as a raster image.

bridge:
A device that links two networks that use the same protocol. This may be used to extend the network or to connect two different network transport technologies (such as EtherNet and Token Ring).

browser:
Software that makes it possible for a networked computer to find and retrieve information over the Internet. Web browsers let you display the graphical information that makes up the World Wide Web.

buffer:
Temporary storage space within a computer system.

bus:
The pathway on a chip or circuit board that sends and receives data. The bus on a computer's main circuit board, often called the motherboard, has slots for expansion cards.

byte:
Eight bits.

cache:
The portion of random access memory (RAM) set aside as a temporary storage or buffer to speed up communications between the CPU and a hard disk or slower RAM.

client/server:
A systems architecture design that divides functions (which might be part of a single application) between two or more computers. The client is the machine that requests information; the server is the machine that supplies it.

compression/decompression:
Compression is the process of squeezing more data into a smaller storage space. Decompression is the retrieval of compressed data and its reassembly to resemble its original form (before compression).

CPU:
Central Processing Unit. The computer's internal storage, processing, and control circuitry.

DAT and DLT:
Digital audio tapes are cassette tapes that store data in digital form for data management purposes. Ideal uses for this inexpensive medium are long-term archival storage. Digital linear tape is effective for long-term storage applications and is best suited for use by high-volume printers, as opposed to desktop publishers.

database:
Any collection of data can be referred to as a database. In the computer field, this term has come to mean a file or set of files that stores data in a retrievable format for later recovery or record-keeping.

digitizing:
To convert an image into binary code. Visual images are digitized by scanning them and assigning a binary code to the resulting vector graphic or bitmapped image data.

domain name:
The Domain Name System, better known as DNS, translates computer names into their associated IP addresses (the numerical address internally used for sending messages), so that you don't need to know the IP address of a computer.

download:
The transfer of information from one computer to another. Frequently used to describe file transfer from a network file server to a personal computer.

email:
An electronic document-exchange tool used for interpersonal communications that can send and receive text, files, and audio items. A central application is responsible for storing the information, forwarding it to the proper recipient, and possibly tracking that activity. A user interface application enables the user to create, retrieve, and send messages.

encryption:
A method of coding that makes files unreadable to those that don't have the decryption code.

EPS:
Encapsulated PostScript. An image storage format that extends the PostScript page description language to include images.

ethernet:
A network protocol that transfers data at 10 Mbits/s across a linear bus topology.

fiber optic:
A technology that uses laser light pulses, sent over thin glass fibers, to deliver at high speeds (up to several gigabits per second).

file server:
A computer running a special operating system that allows authenticated PCs to access files (rather than disk sectors) on a shared portion of its hard disk.

firewall:
Security on the Internet is clearly a vital topic of interest to many people. There are many types of security that can be implemented, but one of the most effective is a hardware and software combination known as afirewall. Basically, a firewall protects a network from many well-known security attacks coming in from the Internet. A firewall acts as a gateway through which all Internet traffic going to a network moves. On that gateway is software that checks all the incoming and outgoing messages looking for anything that might be dangerous. Without assuming that a message is or is not dangerous, the firewall routes the messages to a safe area which is easy to monitor. Most firewall software makes using Internet services a bit more difficult for people on the network behind the firewall. However, if the firewall is set up properly, those people's data is much safer than if the firewall didn't exist. Thus, the tradeoff of security for convenience is often considered a good one.

format:
Formatting: One of the basic tasks handled by the computer's operating system that establishes a pattern for the display, storage, or printing of data. The process of adjusting the appearance of a document.

FTP:
File Transfer Protocol is a service for transferring files between computers. It supports two types of data: binary (which allows any kind of file to be transferred) and text (which restricts transfers to files that contain text only). FTP also allows for unattended file transfer, where you can schedule a file exchange to occur at a particular time (say, late at night when communication costs are lower) and the job will be done without operator interaction.

gateway:
A device that translates data between two systems that are incompatible or that use different protocols.

groupware:
Programs that enable many people on a computer network to work simultaneously on the same file, while viewing the changes made by others as they occur.

hardware:
The actual machine and its physical components that make up a computer.

header:
Technical information packaged with an image or text file, which may be of use in displaying the image or text.

HTML:
Hypertext Markup Language. An encoding format for identifying and linking electronic documents used to deliver information on the World Wide Web.

HTTP:
Hypertext Transport Protocol. A standard used for sharing information on the Internet. It is the basis for the World Wide Web.

hub:
A cabling center in a star topology that either amplifies a signal and transmits it (active hub) or simply passes the signal along (passive hub). This term is properly used to describe such devices in ARCnet networks, but it has become generic, describing all devices used in a back-to-center (home run) cabling configuration. (Examples: 10BaseT EtherNet concentrators and Token Ring MSAUs, which technically are not hubs.)

IP:
Internet Protocols. The standards that enable computer users to exchange data through the Internet.

ISDN:
Integrated Services Digital Network. Offers multiple voice and data channels over the same connection. up to 24 channels running at 64 kilobit/sec are available for a maximum of 1.544 Mbit/s on a single ISDN connection. The biggest problem with ISDN is that it's a little long in the tooth now. When the standard was first proposed it was a fine fit with existing technologies, but subsequent market entrants, such as fast packet systems, have made ISDN less appealing where raw throughput is required.

ISP:
Internet Service Provider. In orer to get access to the Internet, you need to connect to a system that is already on the Internet. For many people, this is one of the major online services such as CompuServe or America Online; for others, it is a local Internet company. All of these companies are called Internet Service Providers, or ISPs, because they provide you with Internet service, similar to the way the local telephone company provides you with phone service.

JFIF:
JPEG File Format. File-storage format for images compressed with the JPEG algorithm.

JPEG:
Joint Photographic Experts Group. Used to refer to the standard they developed for still image compression, which is sanctioned by the International Standards Organization (ISO).

LAN:
Local Area Network. A network of computers and peripherals that spans a small physical area, usually one building or a small campus.

MAM:
Metropolitan Area Network. A network that covers a city (tens of miles) and operates at data rates similar to a LAN. Usually owned by service companies that resell the data service to end-users.

megahertz:
Abbreviated MHz. The unit of measure that describes the rate at which computers operate. A rough guide to computer performance, but not always accurate for comparing capabilities of dissimilar computers.

MIME:
Multipurpose Internet Mail Extensions. A standard for embedding multimedia din in e-mail messages. Regular mail can only contain ASCII characters because of the limitations of SMPT, the protocol used to pass mail between Internet computers. In the past few years, this limitation has become a major problem as more people want to pass pictures, sound and formatted text. To address these problems, a new standard called MIME was developed. MIME allows arbitrary data to be included in mail messages, as long as the header in the mail message identifies the content so that the mail client can read it. In order to use a message with MIME content, you need a mail client that has MIME capabilities. The Unix mail program, mail, doesn't have these capabilities, but most other modern mail programs do. Note that some mail readers support more MIME capabilities than others. For example, elm and Pine are character-based programs, so they don't support displaying pictures or playing sounds; however, they do support reading messages that use the MIME standard for breaking a message into separately-readable parts. MIME has other features that will help establish it as the standard protocol to use in the future. For example, you can add formatting (such as bold and italics) to your plain text messages; you can break a single message into many parts so that the reader can skip parts he or she is not interested in; you can send video segments; and you can even define your own type of data (such as a new kind of picture file) for inclusion. As more people create MIME-enhanced messages, there will be more demand for MIME-compliant mail readers. Within a few years, it will be normal to get voice- and video-mail over the Internet as easily as text mail.

MO:
Magneto-optical technology combines an optical laser with a magnetic field to read and write data on a coated glass or plastic disc. MO storage is well suited for photographic storage.

modem:
A hardware accessory needed to link two computers via the telephone system.

NETBIOS:
Network Basic Input/Output System. A standard for supporting network communications that is independent of the underlying network transport type.

packet switching:
Units of information with headers that may travel individually or in groups on a network.

parallel interface:
An interface between a computer and a printer that enables the computer to send multiple bits of information to the printer simultaneously.

peer to peer:
A network system consisting of workstations that are capable of being both server and client.

PICT:
Macintosh Picture. A storage format for digital images designed primarily for the Macintosh.

pixel:
The picture elements that make up an image, similar to grains in a photograph or dots in a half-tone. Each pixel can represent a number of different shades or colors, depending upon how much storage space is allocated for it.

POP:
Point of Presence. As more people want to get on the Internet, many providers have set up systems throughout the country. Because high-speed networks are much less expensive to run than they used to be, there is often no advantage to having your Internet provider be in your same city. As long as there is a high-speed connection from where you are to the host site, a long-distance works just as well. You may be in New York and your Internet provider's computer may be in California, and the distance would be invisible to you as long as there was a local phone number to call. A point of presence is a bank of modems in a city that is connected through a high-speed connection to the site of the host computer that is connected to the Internet. To the users in that city, the Internet provider has a local presence, even if it is illusory. Some providers have points of presence only in nearby cities; others have points of presence across the country.

PPP:
Point-to-Point Protocol. An Internet standard providing direct connections through telephone lines.

port:
An interface that controls the flow of data between the central processing unit and external devices such as printers and monitors.

RAID:
Redundant array of independent drives storage solutions vary from a simple enclosure of drives, power supply and fan to a modular tower of drives, power supplies, fans and a multitude of high-tech bells and whistles. These are considered most ideal for work-in-process situations. A data management trend today is combining CD-ROM, MO, DAT and DLT technologies with RAID utilization for a more panoramic data management horizon.

resolution, image:
Number of pixels (in both height and width) making up an image. The higher the resolution of magimage, the greater its clarity and definition.

resolution, output:
The number of dots per inch, dpi, used to display an image on a display device (monitor) or in print.

RGB:
Red Green Blue. An additive system for representing the color spectrum using cominations of red, green, and blue. used in video display devices.

router:
A device that links networks that are running different protocols. It can be used to separate unwanted traffic on either side of the bridge, to reduce the traffic, or to provide security from unwanted users.

SCSI:
Small Computer System Interface. A high-speed port used to connect computers with printers and other peripherals.

server:
A PC dedicated to one or more particular services on a network.

SGML:
Standardized General Markup Language.

SLIP:
Serial Line Internet Protocol. An Internet standard providing direct connections through telephone lines.

smtp:
Simple Mail Transfer Protocol is designed for sending text messages. This means anything with more complex data (program files, digitized voice messages, graphics and so on) has to be encoded into a simple text version before transmission. Each piece of mail is simply a text file that includes the addressing information and the message itself.

software:
System, utility, or application programs expressed in a computer-readable language.

SQL:
Structure Query Language. A data-sorting language, used as a front-end or client to make requests of a relational database service.

T1:
Common for links between Internet servers: roughly 1500kbaud, or 12 times faster than fast ISDN.

T3:
The speed of much of the Internet backbone; roughly 25 times faster than T1.

TCP/IP:
The Transmission Control Protocol/Internet Protocol architecture is a collection of standards that was developed in 1969 on a network called ARPANET (Advanced Research Projects Agency Network) to prove the feasibility of wide-area networking. The protocols and ARPANET were so successful that TCP/IP can be found on a wide range of LAN systems, and ARPANET has grown into what is now called Internet.

telnet:
A remote terminal program that enables you to sit at one computer and run programs on another computer. The screen data from the program on the remote computer is displayed on your screen, and the data you type on your keyboard is sent to the remote computer. This is efficient if you're running programs that access large amounts of data on a remote computer. Rather than running the program locally on your machine and hauling the data from the remote company across the network (which could be very time-consuming and would consequently reduce the available network capacity for other users), telnet lets you work on the data where it is (remotely) and use the network to control the access and transfer the results.

Token Ring:
A network transport technology in which a token is passed around in a ring topology, transferring data at either 4 or 16 Mbit/s.

Unix:
An operating system.

UPS:
Uninterruptible Power Supply. A backup unit that provides continuous electrical power when the normal power supply is interrupted.

URL:
Uniform Resource Locator. The way you indicate where you are going on the World Wide Web is with URLs (Uniform Resource Locators). URLs are similar to postal addresses or telephone numbers: you can use them to identify the end point of what you want. Most URL's consist of three parts: the service name, the host name, and the request. For example, a typical URL looks like:

http://www.newsoft.com/internet/paml/:

In this URL, ``http:'' is the service name, ``www.neosoft.com'' is the host name, and ``internet/paml/'' is the request. It is common to have URLs where the request is just a single ``/''. The most common service names you see in URLs are ``http:'', `gopher:'', ``ftp:'', and ``news:''. These refer to Web servers, Gopher servers, FTP servers, and Usenet news servers, respectively. A few URLs do not have a host name. The only ones of this type that you normally see are mailto: URLs that give an email address such as: mailto:chrisr@english.small.edu

VGA:
Video Graphics Array. The 8-bit graphics standards for video output on PCs, which feature 640 x 480 resolution and 256 colors.

WAN:
Wide area network. Any network that covers a wide area and requires special communication devices to make connections possible. The largest differences between WANs and LANs are the need to make connections over long distances and the need for telephone, satellite, or microwave equipment to facilitate the connection.

x86:
A series of microprocessor chips manufactured by Intel. They range from the older, less powerful 286 and 386 chip ๘he the more recent and more powerful Pentium and Pentium Pro.


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