Glossary of technical terms

Batch File

A text file that is used to perform simple tasks. DOS batch files use the extension .BAT. This type of file is run by entering the name of the file at a command prompt like C:\.

Caveat Emptor

Latin for "Let the buyer beware". In these technical pages it signifies a warning.

CD-ROM

Compact Disc-Read Only Memory. A small round, flat object used to digitally store data. Like CDs used to store and replay audio, the CD-ROM is read only (as the name indicates). It is made up of a three layers: a polycarbonate plastic substrate (the innermost layer), a thin reflective metal (where the digital data is stored), and a lacquer coating (to make it stiff and prevent scratching the metal). When the CD-ROM is being created, the digital data is put onto the edisc by a laser. The laser makes little pits in the smooth surface of the metal (think of the grooves on a record). When the disc is inserted into a CD-ROM drive of your computer, another laser reads the pits to reproduce the data for you. Even though audio CDs and CD-ROMs use different methods for encoding information of the surface of the disc, both are commonly called by the same name: CD.

CD Changer

A multi-CD disc storage system that has only 1 laser. To read multiple CDs, the discs are swapped in and out of the laser's path. A bit like an old-time record jukebox.

CD-R or CD-RW

CD-Recordable or CD-ReWritable. Both look like standard CD-ROM discs. CD-R is a write-once/read-many format, in which a layer of dye is between the substrate and metal layers. This dye is permanently changed by exposure to a paticular kind of light. If you have a CD-R or CD-RW drive in your computer you can create your own CD, by using a CD-R disc. CD-RW drives must be used to create reusable CD-RW discs. A layer of alloy is between the substrate and the metal. When a specific kind of light shines on the alloy it changes into a crystallline structure, storing the data. Using a process called optical phase change, the disc can be returned to its origianl state. The disc can then be reused. This sounds like a great idea, but the drives that are playing the discs must be very sensitive, because the patterns created by the crystalline structuren aren't as precise as those created by other CD formats. Many CD-ROM drives can't read CD-RWs.

CD Tower

An array of multiple CD-ROM drives. For example a 4-Bay Tower has 4 individual CD-ROM drive bays in an enclosure.

Client

A PC connected to the network. Can function independently, or as a peer, in addition to requesting programs and services from the network server.

CSMA/CD

Carrier Sense Multiple Access/Collision Detect. The Ethernet protocol for sending signals through the wire. Any device can try to send a packet at any time. A device will sense whether the line is idle. If it is, the device sends its first packet. If another device has tried to transmit data at the same time, a collision happens and the packets are discarded (or dropped). Each device then waits a random amount of time before retrying until its transmission is sent.

DHCP

Dynamic Host Configuration Protocol is a method that manages and automatically assigns IP addresses to workstations. A pool of address is stored on a DHCP server, this may or may not be the main network server. Each workstaiton requires a unique IP address. When a workstation logs onto the network, the DHCP server temorarily leases an address from its pool to the workstation. When the workstation logs off the network, the address is returned to the pool. The returned address can then be assigneed to another computer as it log into the network. In this way, a network can have more computers than IP addresses.

DOS

A computer operating system. Originally called QDOS, the name stood for Quick and Dirty Operating System. The title referred to the fact that this operating system was fast and efficient. The system was purchased by Microsoft in the early 1980's and renamed MS-DOS (for Microsoft Disk Operating System). Some people will tell you that Microsoft invented DOS; don't you believe it. DOS is a text based, command line oriented system. The ytpical command line looks linke this: C:\

Driver

The small software code that the operating system uses to allow a device to function. Every device has a driver. Some are loaded automatically by the operating system; like those for hard drives, floppy drives, keyboards and monitors. Some must be manually added to the operating system; like those for netowork cards, or SCSI cards.

DVD

Digital Versatile Disc. A DVD has the same size and appearance as a CD-ROM, but is capable of storing significantly greater amounts of data.

Ethernet

A network communication protocol that allows workstations to communicate with each other by sending data along an Ethernet cabling system. It is the most common type of network cabling. Each device on the network may "talk" at any time, but if two or more signals collide, then the PC waits for an assigned period of time before resending. This process is CSMA/CD

Firewall

Programs and any related hardware that protect the users of one network from the users of any other network (i.e., to protect a network from the Internet). The program usually works in conjunction with a router, a hub-like device that can restrict the flow of data.

GUI

Pronounced "gooey". A Graphical User Interface is the method that lets you work with your computer. The screen is a kind of picture (graphic) that you (the user) manipulate to use (interface with) Windows or Macintosh. All new operating systems use a GUI. Old systems used a text based system that required the user to type commands at a prompt to use the computer.

Hub

A hub is the central point of a network; although it doesn't need to be physically equidistant from every device. Every Ethernet cable that is connected to a network device at one end is connected to the hub at the other end. All information flows through the hub as it passed from one device to another.

ISA

Industry Standard Architecture. A 16-bit expansion card developed in the mid-80's by IBM. An ISA card will fit into a black expansion slot of the PC's motherboard.

LAN

Local Area Network. A network, either peer or client/server based, that is at a specific site. Usually one office, or building.

Mbps

Megabits per second. One million bits (binary digits) per second. A bit is a pulse of eletromagnetic energy. And Mbps is the standard method for indicating the speed with which data travels. Most people are familiar with modem speeds; 14.4Mbps, 28.8Mbps, 56Mbps, etc.

Motherboard

The large printed circuit board that computer's basic circuitry and components. The microprocessor (Intel Pentium, AMD Athlon, etc.), memory (RAM), basic input/output system (BIOS) and expansion slots (ISA or PCI) are attached to the motherboard.

NAS

Network Attached Storage. Hard drive storage that is assigned a network address, rather than being attached directly to a workstation or server. By removing the storage from the workstaiton you manage the amount of permissible storage space and can allow the data to be accessed from multiple sites. By removing the storage from the server you decrease the load from the server and increase network response times. RAID Is possilbe with NAS

Network card or NIC

A Network Interface Card is an expansion board that allows a PC to connect to a network.

OS

Operating System. Windows 95/98/ME and Apple's Macintosh are operating systems. It is the computer program that manages all the other programs in a computer. All other programs (word processors, spread sheets, games, etc.) are applications that make requests for computer resources (hard drive space, RAM usage, printer output, etc.) through the OS. An OS may provide a graphical user interface (GUI) like Windows or Mac. Or it may be text based like DOS.

PCI

Peripheral Component Interconnect. A 32 bit expansion card developed by a consortium of PC manufacturers to provide better performance in Pentium-based computers. A PCI card will fit into a white expansion slot of the PC's motherboard.

PCMCIA

An expansion card for late model notebook computers. Physically about the size of a credit card

Peer-to-Peer network

A network of PCs that do not request programs and services from a server. Each peer workstation can allow other workstations access to its resources. Usually Windows 95, or Windows for Workgroups.

RJ-45 UTP

This is the technical specification for Ethernet network cabling: RJ-45 is a single-line jack for digital transmission over ordinary phone wire, and unshielded twisted pair is the most common kind of copper telephone. To reduce crosstalk or electromagnetic interference between pairs of wires, two insulated copper wires are twisted around each other. Each signal on twisted pair requires both wires. There are 4 pairs, or 8 wires used in Ethernet and the cable appears round, unlike ordinary telephone wire that appears flat. Category5 Ethernet cable is constructed to the RJ-45 UTP standard.

SCSI

Small Computer System Interface. Pronounced "Scuzzy". Initially developed for hard drives, it has become a versatile cross-platform standard for many types of devices; CD-ROM drives, scanners, ZIP drives, and more.

Server

A computer which runs the network, controls the flow of data, and authorizes user requests. Usually running the Novell NetWare or the Microsoft NT network operating system.

TCP/IP

A suite of network protocols that provide a common communication language for dissimilar network devices. Commonly used to connect to the Internet.

10BaseT

10Mb per second Ethernet cabling. Pronounced "Ten-Base-T".

100BaseT

100Mb per second Ethernet cabling. Pronounced "One-Hundred-Base-T".

Token Ring

A network communication protocol that allows workstations to communicate with each other over sending data along a Token Ring cabling system. A "token" is passed to each device on the network in a circular path. The device can "talk" only while it has the token. During that time all other devices must "listen". See Topology.

Topology

The conceptual layout of a computer network. It doesn't actually refere to wher you place the computers. Ther are 3 types: bus, ring and star. In a bus topology, data packets are sent from one computer to another until the packet reaches its destination. Many devices may attempt to send a packet at any one time. Each computer gets the packet, but those to whom the packet is not addressed simply drop it (see Ethernet). In a ring, only one device can send a packet at any one time.Each computer gets the packet, but those to whom the packet is not addressed simply drop it (see Token Ring). A star topology allows two computers to send packets directly to each other, without any other device receiving the packet.

Virtual CD-ROM disc

Data copied from a physical CD-ROM and stored on a large hard drive. It will behave as a physical CD-ROM when "inserted" into a Virtual CD Drive Bay.

Virtual CD Drive Bay

Appears in the Windows 95 environment as a physical CD but is actually intangible.

WAN

Wide Area Network. A network, usually client/server based, that is made up of several sites. A WAN is so large that it is normally spread over several buildings, cities, or countries. The "Internet" or "World Wide Web" is a WAN.

Windows 9x/ME

Windows 95, 98, or Millenium Edition. These three operating systems are variations of the same kernal, or core, software. A program that works in 95 will probalby work in 98 or ME. Collectivley there are referd to as 9x/ME. The number refers to the year the software was introduced. If you were wondering why Microsoft didn't use the same pattern in naming the latest verison; they had used the number 2000 with a different kind of software, so they were forced to name the product "Millenium" instead.

Workstation

See Client.