- 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 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.
- 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
- The Basic Input/Output System - The low level code used to do power-on
system tests and start the boot process.
- 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 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.
- 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.
- 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
- 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.
- 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).
- 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'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).
- 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).
- 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.
- 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.
- 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
- The software used to configure the Linux kernel's ability to firewall,
forward, and masquerade network data.
- 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.
- The software tool commonly used on Linux machines to configure plug and
play ISA expansion cards as a Linux machine boots.
- 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.
- 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
- 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
- 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
- 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
- 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.
- 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
- 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
- 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
- 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.
- 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
- 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
- Peripheral Component Interconnect - The later standard
interface for adding expansions card to a PC. Supports plug
and play and has largely replaced ISA.
- 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.