Terms
1999.12.02.02

ADSL

Asymmetric Digital Subscriber Line - A service one may have added to one's phone line for high speed computer data connections. Speeds range from 384kbps/128kbps (down/up) to 6Mbps/384kbps. Download speed is faster than upload speed, so ADSL is not ideal for serving large amounts of data to people not within one's local network. The primary competition for ADSL is cable modems. see also SDSL and xDSL

at

at is a Unix program that can be used to automatically start other software or scripts at a predetermined time. It is included with most all Unix variants, though cron is a more popular alternative.

BIND

The Berkeley Internet Name Daemon - The most popular of the existing name servers. It translates the rather difficult to remember IP addresses that one encounters into the more friendly hostnames (and vice versa). It is often also referred to as "named." see also DNS

BIOS

The Basic Input/Output System - The low level code used to do power-on system tests and start the boot process.

BOOTP

One method for a computer to request an IP address at boot time. A newer, more popular, and more flexible alternative is DHCP.

cable modem

A device that connects the the same cable as one's television to provide Internet access at high speeds. In the Austin area this service is offered by TimeWarner since they have the Austin area cable franchise. Speeds range from 128kbps up to 10Mbps depending on overall network load within Time Warner's system. The primary competition for cable modems is ADSL.

cron

cron is a Unix program that can be used to automatically start other software or scripts at a predetermined time. It is included with most all Unix variants, and is usually used to start periodic maintenance scripts once a night, week, and month. at is an alternative.

DHCP

Dynamic Host Configuration Protocol - A method for a computer to request an IP address (and related information) at boot time. This has become quite popular due to the increasing scarcity of unallocated IP addresses on the Internet. An older alternative is BOOTP.

Disk Druid

The hard drive partitioning tool included in the Red Hat Linux installer for version 6.0. It has a more friendly interface than the alternative, which is fdisk.

DNS

The Domain Name System - A large set of servers on the Internet that contain and maintain the distributed database of IP address to hostname mappings. see also BIND

Ethernet

One of the most popular types of computer networks. Commonly uses twisted pair cable (a.k.a. category 3 or 5 UTP) and thin coax (a.k.a. BNC). It usually runs at 10 megabits per second, 100 megabits per second, and 1 gigabit per second speeds.

fdisk

The traditional Linux partitioning tool. It has the same purpose as the DOS version of fdisk, though its interface is more arcane. It is one of the two options for partitioning during the Red Hat install process (Disk Druid is the other).

firewall

A computer that acts as a gateway between two networks (usually a private network and the Internet). A firewall also provides some sort of security to the private network. It does not provide any content filtering; though some software running on the firwall may do so, it is not very common.

GNU

GNU's Not Unix - A project to build a completely open source (and free) Unix variant or clone. The creators of the GPL. Much of the software that comes in a Linux distribution such as Red Hat Linux is written as a part of the GNU project (notably including the compiler).

GPL

The General Public License - The open source software license written for the GNU project. One of the most free and open software licenses in existence. It stipulates that software written and released under it must be available for free to the general public, and that people other than the author are permitted and encouraged to make additions to the software, but that such additions must also be released under the GPL. It, however, does not forbid people from selling collections of such software, as long as those collections are also available freely (such as Red Hat Linux, which has a commerical version that includes support and documentation, and a free version one may download from the Internet).

IDE

Integrated Drive Electronics - One of two popular hard drive interfaces used in personal computers. IDE drives are usually cheaper than drives using SCSI, the primay competing interface. However, SCSI drives often provide better performance in demanding situations.

IMAP

Internet Mail Access Protocol - A method of accessing Internet e-mail from a client computer. Often used as an alternative to POP3 since it does not require a client machine to download all the messages simply to read them. However, it is newer than POP3 and hence less often supported.

inetd

The TCP super server. A Unix program that starts several services only when they are needed so that they don't consume system resources when they are not in use. Some of these services are telnet, POP3, and IMAP.

IP Masquerading

The implementation of network address translation (NAT) included with the Linux kernel.

ipchains

The software used to configure the Linux kernel's ability to firewall, forward, and masquerade network data.

ISA

Industry Standard Architecture - The older standard interface for adding expansion cards to a PC. It didn't originally support plug and play, though that ability was added later. ISA is now largely replaced by PCI.

isapnp

The software tool commonly used on Linux machines to configure plug and play ISA expansion cards as a Linux machine boots.

ISDN

Integrated Services Digital Network - One type of digital phone line commonly used for Internet connectivity. Commonly used with a router such as the Ascend Pipeline series in speeds of 64kbps or 128kbps.

kernel module

A piece of code that can be dynamically added to or removed from the Linux kernel when needed or not. This feature is commonly used to load and unload drivers depending on what hardware is in a given computer without making a very large kernel.

LILO

The Linux Loader - The piece of software that takes over right afteer the BIOS finishes system tests. It remembers the physical location on the hard drive where the kernel lives so that it can load the kernel and transfer system control, so that Linux can really being to do cool stuff. :-)

Linuxconf

The Linux Configurator - A program and a set of modules that allow a person to do a great deal of configuration and administration of a Linux system in an easier-to-understand interface than the command line and a bunch of text files.

Lynx

A text mode web browser. It is quite useful when you have no graphical interfact such as X Windows, or just need a fast web browser.

mail spool

The collection space on a mail server for incomaing mail. On Linux machines the mail spools for individual users ususally live in /var/spool/mail so a mail spool for a user named jarehart would be /var/spool/mail/jarehart. Programs such as sendmail and the POP and IMAP servers deal with these files, so usuers don't usually do so directly.

man

The manual page reader. This is the nice, but also annoying command that can help you figure out how to do something on a Unix system. see also manual page

manual page (a.k.a. man page)

The actual information about a given program. The idea is that if you had the inclination, you could print all the manual pages out and actually have a paper manual. Manual pages usually come with software and are added to your system when a given program is installed. see also man

MD5

An encryption system often used to strengthen security of passwords on Linux systems. Even when it is enabled, the older method of encrypting passwords on Unix systems continues to work.

named

see BIND

network address translation (NAT)

A system by which a set of computers are "hidden" from the general Internet by a router of some sort. This is often done to conserve IP addresses due to the growing shortage of unallocated addresses; or to allow multiple computers on the Internet through a connection that is only ever given one address. The idea is that the computers behind the router use a set of addresses that were reserved for TCP/IP based networks that were not going to be attached to the Internet. Then the router takes data leaving the private network destined for the Internet and changes the source address to be the "real" address of itself (not the "hidden" machine that originally sent the data). It makes a note of the change it made, and sends the data on its way. When a response comes back the router then undoes the change it made and hands the data off to the "hidden" machine. This works transparently and rather well for most all Internet transactions. see also IP Masquerading

NFS

The Network File System - A method of file sharing often used on Unix systems. It was originally developed by Sun Microsystems, but later became a de-facto standard.

NIC

Network Interface Card - The electronics that teach your computer how to speak to a network. There are different types depending on which cable you have and how fast you want to send and receive data. see also Ethernet and Token Ring

NIS

The Network Information System - A method, originally developed by Sun Microsystems, to share user account information (usernames, passwords, etc.) across a network to multiple Unix systems.

package

A storage file similar to a PKZip file or an installer. They are usually used to install software on Unix systems though they don't actually include the install engine, just the information so that the install engine knows where to install the software and on what other software (if any) a new package depends. see also RPM

partition

A division of a physical hard drive. They usually appear to an operating system as separate disks, though they are on the same physical drive. Linux uses partitions to separate swap space from the rest of a filesystem, and can also use them to segment the filesystem, though this is not always done.

PCI

Peripheral Component Interconnect - The later standard interface for adding expansions card to a PC. Supports plug and play and has largely replaced ISA.

PCMCIA

Personal Computer Memory Card Industry Association (I think <grin>) - A standards group which defined an interface for credit-card-sized expansion cartridges. They were originally used to add flash memory to laptops and other small computing devices, though the PCMCIA interface is now used for modem, network cards, and other devices.

PNP
POP (POP3)
proxy
router
RPM
SCSI
SDSL
sendmail
shadow passwords
SMB (Samba)
SMTP
Squid
ssh
swap
SYSLINUX
TCP/IP
telnet
Token Ring
UDMA
Usenet
X Windows
xDSL