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Glossary
- RADIUS
- Remote Authentication Dial In User Service
See: RFC-2058
- RAM
- Random Access Memory -- this is a type of computer
memory that can have its stored information be changed (written to or
retrieved) at any given time. When a computer is shut off (no power
goes to the computer), any data contained in the machine's RAM (system,
RAM, video RAM, etc.) is removed or "flushed."
Example hardware that stores RAM:
hard drive
floppy disk
SIMMs and DIMMs
Common types of RAM:
DRAM (Dynamic RAM)
SRAM (Static RAM)
WRAM (Windows RAM) -- RAM typically found on
graphics/video controlers optimized for use with
Microsoft Windows
NVRAM (Non-volatile RAM) -- this is RAM that is
not lost when the power is lost. NVRAM is often used in
modems to store user-defined
initialization strings and other commonly used attributes.
See also: ROM
- Resolution
- Pixel density -- how many pixels are grouped together
in a matrix (rectangular area). Resolution is measured by horizontal
pixels and vertical pixels (horizontal x vertical). Sometimes color
depth is seen with resolution specifications (horizontal x vertical x color-depth).
When refering to video resolution (monitor or video/graphics controler),
the amount of horizontal and vertical pixels is relative to the computer
monitor's display-area dimensions. An image displayed at 1024 x 768 resolution
on a 14" monitor will appear rather small due to the monitor's relative dimensions.
If the same image is displayed at the same resolution on a 21" monitor, the
same exact amount of the image will be displayed, but because the monitor's
larger size, the image will appear larger. The higher the resolution, the
more you'll see on the screen, but because you're fitting more on the
screen (in the same physical dimensions), the smaller the individual items
in the image (such as icons, characters, etc.) will appear.
Common resolutions for video/graphics controlers and computer monitors:
320 x 200 -- (CGA/EGA)
640 x 480 -- (VGA - Video Graphics Array)
800 x 600 -- (SVGA - Super VGA)
1024 x 768 -- (EVGA - Extended VGA)
1280 x 1024
1600 x 1200
Common resolutions found on dot-matrix, ink-jet, and laser printers
(measured in dots (pixels) per inch):
180 x 180
360 x 180
300 x 300
360 x 360
600 x 300
600 x 600
720 x 360
720 x 720
See also: Pixel
- Retrain
- A retrain is the same thing as an initial "handshake" when two modems,
first connect, but retrains occur after a connection has already been
established. Retrains are usually initiated because of a degradating
connection--often a result of line noise or some
form of interference on the phoneline. Poor ventilation around a
high-speed modem can cause it to get quite hot, and that could cause
communications problems, leading to a potential retrain. When modems
retrain, they attempt to re-establish a reliable connection, often
varying the connection speeds. While modems are retraining, no data
can be sent or received between the computers--only the modems are
communicating at this point, and depending on line quality/conditions,
retraining may take as little as about 10 seconds to a couple of minutes.
- RFC-number
- Request For Comments is a series of documents published by the
Internet Engineering Task Force (IETF)
and cover a broad range of topics. The core topics are the Internet and
the TCP/IP protocol suite.
See: RFC documents
- RIP
- Routing Information Protocol
See: RFC-1058 and
RFC-1723
- Requiescat In Pace -- Latin, meaning "May he/she/it
rest in peace." RIP does NOT stand for "Rest In Peace"--RIP had been in
use long before the English language existed.
- ROM
- Read-only Memory -- this type of memory cannot have
its contents changed once stored, except in the cases of "Flash ROM" and
EPROM. Flash ROM allows its contents to be software-upgradeable, but the
contents are usually not lost when the power is lost.
Example hardware that stores ROM:
CD-ROM
modem ROM chip -- stores programming information
and interprets "AT commands" so that the
modem operates properly
See also: RAM
- RPI
- Rockwell Protocol Interface - A low-cost,
software controled alternative to hardware-based V.42 error correction
and V.42bis data compression that was used on many cheaper 14.4 kbps
modems. WinModems are their newer "cousins."
See: V.n
- RTFM
- Read The F-ing Manual -- I only listed this
because it's posted all over the internet and many people don't know what
it is...
- SGML
- Standard Generalized Markup Language
See: RFC-1874
- SIMM
- Single In-line Memory Module -- a removeable
and replaceable piece of hardware for storing
RAM, using DRAM chips.
Common types of SIMMs:
| 1 x 8 |
1MB, 30-pin, 8-data-bit, non-parity checking SIMM often used
in older Apple Macintosh computers. |
| 1 x 9 |
same as a 1 x 8 SIMM, but has an extra bit for parity-checking.
This type of SIMM was often used in Intel
("IBM")-compatible computers ("PCs") until about
1992 when they were replaced by 72-pin SIMMs. |
| 4 x 9 |
same as the 1 x 9 SIMM, but had the capacity of 4MB. |
| 1 x 32/36 |
4MB, 72-pin, 32-data-bit SIMM. n x 32 SIMMs are non-parity
checking and are most often used in newer Apple
Macintosh computers and newer PCs. n x 36 SIMMs have
4 extra bits for parity checking and are still used in some PCs. |
| 2 x 32/36 |
same as 1 x 32/36, but has the capacity of 8MB. |
| 4 x 32/36 |
same as above, but has the capacity of 16MB. |
| 8 x 32/36 |
same as above, but has the capacity of 32MB. |
SIMMs are installed into computers in quantities that are regulated
by the computer's CPU and how many bits of data
can/are addressed by the CPU at a time. The
Intel 386sx addressed memory
16 bits at a time, and used 1 x 9 SIMMs in pairs. The
Intel 386dx and 486 (all)
processors address memory 32 bits at a time, so if
the computer uses 30-pin SIMMs, they are addressed
4 SIMMs at a time. If the computer uses 72-pin SIMMs, they are
addressed individually. The
Intel Pentium and Pentium Pro
computers address memory 64 bits at a time, so 72-pin SIMMs are
addressed in pairs.
See also: DIMM
- SLIP
- Serial Line Internet Protocol --
Info...
See: RFC-1055
- SMTP
- Simple Mail Transfer Protocol -- This is
a protocol for sending e-mail across the
internet. An SMTP server is a computer that transmits e-mail
from one computer network to another across the internet.
See: RFC-821
- SNMP
- Simple Network Management Protocol -- a
protocol used by some computer networks that allows for administration
of that network by a computer connected, remotely (e.g. by
modem).
See: RFC-1157
- TACACS
- Terminal Access Controller Access Control System?
See: RFC-1492
TCP/IP
- (Internet) Transmission Control Protocol / Internet Protocol --
The TCP protocol provides reliable, flow-controlled, two-way
transmission of data. It is a byte-stream protocol used to support the
SOCK_STREAM abstraction. TCP uses the standard Internet address format
and, in addition, provides a per-host collection of "port addresses."
Thus, each address is composed of an Internet address specifying the
host and network, with a specific TCP port on the host identifying the
peer entity. (Description obtained from the UNIX "tcp" manual page)
See also: IP
- Telnet
- tele (Greek, meaning "far off") network -- a protocol used to log onto other computers on the internet via
a VT terminal or terminal emulator.
See also: URL
See: RFC-854
- Tera
- Tera is a prefix to a unit of measurement representing 10^12 (1,000,000,000,000) in SI (Systeme
International) terms, using base-10 (decimal) numbering. In
computer terms, it's the closest decimal number to 1,000,000,000,000 based on base-2
(binary) and is equivalent to 2^40 (1,099,511,627,780).
Abbreviation: T
See: Proposed prefixes for binary multiples
See also: kilo, Mega, Giga
- tn3270
- telnet 3270 -- This is a
telnet link to IBM mainfraims in the 3270 family.
See URL.
- TTY
- Teletype
- UART
- Universal Asynchronous Receiver/Transmitter
A buffer that a modem uses when sending and receiving data. The 3 most
common UARTs that are currently out there are:
| 8250 |
Commonly used until mid 1994. This UART can handle speeds up
to 9600 bps. Modems that are faster that are connected to serial
controlers with this UART will usually have transmission and/or
file transfer problems due to this. |
| 16540 |
A newer version of the 8250. It can handle the same speeds as the 8250. |
| 16550 |
This is the among the latest family of UARTs, capable of handling
DTE speeds up to 115200 bps. |
Info can be found at:
http://www.connecttech.com/KnowledgeDatabase/kdb039.htm
Most internal high-speed modems now come with the 16550 UARTs.-->
- Unix
- Unix is a family of command-line-driven 32-bit operating systems. Unix is not
an acronym, however the name "Unix" was half-jokingly named after an
operating system developed by MIT, called
Multics.
Some common "flavors" of Unix include: Irix, SCO-Unix, Linux, AIX,
SunOS, Ultrix, HP-UX, etc.
Later, a graphical interface became available for Unix, called X-Windows.
- Upload
- Transfer a file or other data from the computer you're using, to another
computer, elsewhere.
See also: Download
- URL
- Uniform Resource Locator -- This is the protocol,
address, and/or file for whatever you happen to be viewing at any given
time on the Web.
Various protocols used in URLs:
- http
Example: http://support.talstar.com/glossary/q-z.asp
"http" is the protocol, "support.talstar.com" is the domain name,
"/glossary/" is the directory (folder), and "q-z.asp" is the file.
RFC-1700 port number: 80
- ftp
RFC-1700 port number: 20
- gopher
RFC-1700 port number: 70
- mailto
This protocol launches a mail program allowing the user to send mail
to the specified address via SMTP.
Example: mailto:support@talstar.com
"mailto" is the protocol and "support" is the mail account on the domain,
"talstar.com".
RFC-1700 port number: 25
- news
The news protocol will bring up the specified USENET
newsgroup(s) if the webbrowser supports it and if the news
(NNTP) server has access to the newsgroup(s).
Example: news:news.newusers.questions
"news" is the protocol and "news.newusers.questions" is the specific
newsgroup.
RFC-1700 port number: 119
- telnet
RFC-1700 port number: 23
- tn3270
RFC-1700 port number: 23
- USENET
- For a description see: http://support.nettally.com/faq/usenet.asp
See: RFC-1036
See also: NNTP -- Network News Transfer Protocol
- V.n
- Standardizations and standardization recommendations by the ITU
for data communication over the telephone network.
For a listing of these with brief descriptions, see the following links:
http://www.itu.ch/itudoc/itu-t/rec/v
Common numbers:
- V.17
A 2-wire modem for facsimile applications with rates up
to 14,400 bps
- V.22
1200 bps duplex modem standardized for
use in the general switched telephone network and on
point-to-point 2-wire leased telephone-type circuits
- V.22bis
2400 bps duplex modem
using the frequency division technique standardized for use
on the general switched telephone network and on
point-to-point 2-wire leased telephone-type circuits
- V.32
A family of 2-wire, duplex modems operating at data
signalling rates of up to 9600 bps for use
on the general switched telephone network and on leased
telephone-type circuits
- V.32bis
A duplex modem operating at data
signalling rates of up to 14,400 bps for
use on the general switched telephone network and on leased
point-to-point 2-wire telephone-type circuits
- V.34
A modem operating at data signalling rates of up to
33,600 bps for use on the general switched
telephone network and on leased point-to-point 2-wire
telephone-type circuits
- V.38
A 48/56/64 kbit/s DCE standardized for
use on digital point-to-point leased circuits
- V.42
Error-correcting procedures for DCEs
using asynchronous-to-synchronous conversion
- V.42bis
Data compression procedures for DCEs using error
correction procedures
- V.90
A digital modem and analog modem pair for use on the Public Switched
Telephone Network (PSTN) at data signalling rates of up to 56,000
bps downstream and up to 33,600
bps upstream.
- Video/Graphics Controler
- The video (graphics) controler is what handles the processes in the
computer for displaying anything on the computer's monitor. Your
computer's monitor is connected to your computer's video controler.
See also: Video RAM
- Video RAM
- Video RAM is memory dedicated for use by the
video/graphics controler. Depending on
the model computer or video controler you have, the RAM may be upgradeable,
usually allowing for greater resolutions and
color depths.
See also: Pixel and Resolution
Typical resolutions, color depths, and video memory requirements:
Resolution Color Depth Memory Required (bytes)
---------- ----------- ---------------
640 x 480 256 307,200
65,536 614,400
16,777,216 921,600
800 x 600 256 480,000
65,536 960,000
16,777,216 1,440,000
1024 x 768 256 786,432
65,536 1,572,864
16,777,216 2,359,296
1152 x 864 256 995,328
65,536 1,990,656
16,777,216 2,985,984
1280 x 1024 256 1,310,720
65,536 2,621,440
16,777,216 3,932,160
1600 x 1200 256 1,920,000
65,536 3,840,000
16,777,216 5,760,000
- VT-n
- Virtual Terminal -- a terminal (later, a terminal emulator)
that was developed by DEC
(Digital Equipment Corp.)
The VT-100 is the most common type of VT terminal or terminal emulator
(often used for telnet connections between
computers on the internet). Some others are VT-52, 102, 220, and 320.
- WAN
- Wide Area Network -- a group of inter-connected
computer networks. These networks could be varioius LANs
within a building or spread throughout a city/town. Some would consider
the internet a WAN.
- WINS
- Windows Internet Naming Service --
WINS dynamically manages the mapping between friendly names and IP
addresses of network resources in a Windows NT Server-based network.
With WINS, end users and applications can access different network
resources using friendly machine names instead of the more cumbersome
and difficult-to-remember IP addresses. Administrators benefit from
not having to manually maintain the mapping between names and IP
addresses.
- WWW (W3)
- World Wide Web
- X.n
- Standardizations and standardization recommendations by the ITU
for data networks and open system communication.
For a listing of these with brief descriptions, see the following links:
http://www.itu.ch/itudoc/itu-t/rec/x
Others: http://www.itu.ch/itudoc/itu-t/rec
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