| 10 Gigabit
Ethernet |
An Ethernet
technology that transmits at 10 Gbps. Abbreviated 10 GbE and
introduced in 2002, it enables the familiar Ethernet technology to
be used in LAN, MAN, WAN and storage network architectures. The CSMA/CD
method for gaining access to the physical medium is not employed,
and only full-duplex operation is supported. A "WAN interface
sublayer" (WIS) makes 10 GbE compatible with the SONET
transport at 10 Gbps (OC-192).
The 10GBASE-LX4 version (see below) carries four wavelengths of
light on one pair of fibers. In 2004, 10 Gigabit Ethernet over
Copper was introduced. Using four twinaxial cables, the copper
version was designed for short distances between switches and
storage devices in the datacenter. See Ethernet.
10 GIGABIT ETHERNET OVER FIBER (IEEE 802.3ae)
Version Use Fiber Max. Distance
10GBASE-SR Dark fiber MMF/850 nm 65 meters
10GBASE-SW SONET MMF/850 nm 65 meters
10GBASE-LR Dark fiber SMF/1310 nm 10 kilometers
10GBASE-LW SONET SMF/1310 nm 10 kilometers
10GBASE-ER Dark fiber SMF/1550 nm 40 kilometers
10GBASE-EW SONET SMF/1550 nm 40 kilometers
10GBASE-LX4 Dark fiber MMF/1310 nm 300 meters
10GBASE-LX4 Dark fiber SMF/1310 nm 10 kilometers
MMF = multimode fiber
SMF = singlemode fiber
10 GIGABIT ETHERNET OVER COPPER (IEEE 802.3ak)
Version Use Cable Max. Distance
10GBASE-CX4 Datacenter Twinax 15 meters
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|
| 100BaseT |
| Also called "Fast Ethernet," it is a
100 Mbps version of Ethernet (IEEE 802.3u standard). 100BaseT transmits at 100 Mbps rather
than 10 Mbps. Like regular Ethernet, Fast Ethernet is a shared media LAN. All nodes share
the 100 Mbps bandwidth. 100BaseT uses the same CSMA/CD access method as regular Ethernet
with some modification. Three cabling variations are provided. 100BaseTX uses two pairs of
Category 5 UTP, 100BaseT4 uses four pairs of Category 3, and 100BaseFX uses multimode
optical fibers and is primarily intended for backbone use. |
|
| 10Base2 |
An earlier 10 Mbps Ethernet standard that uses
a thin coaxial cable. Network nodes are attached to the cable via T-type BNC connectors in
the adapter cards. Also called "thin Ethernet," "ThinWire,"
"ThinNet" and "Cheapernet," 10Base2 has a distance limit of 607 feet.
See Ethernet.
10Base2 "Thin" Ethernet 10Base2 uses a thin coaxial cable that is
attached to each node using BNC T-connectors. |
|
| 10Base5 |
The original IEEE 10 Mbps Ethernet standard
which uses a thick coaxial cable. Network nodes are attached via transceivers that tap
into the cable and provide a line to a 15-pin plug in the adapter card known as the AUI interface. Also called "thick Ethernet,"
"ThickWire" and "ThickNet," 10Base5 has a distance limit of 1,640 feet
without repeaters. See Ethernet.
10Base5 "Thick" Ethernet 10Base5 was the first Ethernet and uses a bus
topology. Transceivers connect the network adapters to a common coaxial cable. They often
use a vampire tap that "bites" into the coax. |
|
| 10BaseF |
A 10 Mbps Ethernet standard that uses optical
fibers. All stations connect in a star configuration to a repeater or to a central
concentrator. Connections are made via ST or SMA fiberoptic connectors. Adapter cards with
AUI connectors are connected to 10BaseF networks via a fiber-optic
transceiver.
The 10BaseFL standard defines the link between the concentrator and a station; 10BaseFP
defines a star-coupled network; 10BaseFB defines a fiber backbone. See Ethernet. |
|
| 10BaseT |
A 10 Mbps Ethernet standard that uses twisted
wire pairs (telephone wire). All stations connect in a star configuration to a central
hub, also known as a "multiport repeater," or to a central switch. 10BaseT has
been widely used due to the lower cost and flexibility of installing twisted pair. It has
mostly been superseded by 100BaseT, which is 10 times as fast. See
Ethernet.
10BaseT "Twisted Pair" Ethernet 10BaseT and 100BaseT are the most popular
Ethernets. All nodes connect to a central hub or switch using twisted pair wires and RJ-45 connectors. |
|
| 128-bit graphics accelerator |
| A display adapter that has a pathway 128 bits
wide between its on-board graphics processor and memory (video RAM). |
|
| 2-D |
| (2 Dimensional) Refers to
objects that are constructed on two planes (X and Y, height and width, row and column,
etc.). Two-dimensional structures are also used to simulate 3-D images on screen. |
|
| 24-bit
color |
| Using three bytes per pixel in a color image.
Also called "true color" and "RGB color," up to 16,777,216 colors can
be represented in the color palette. See bit depth and bit specifications. |
|
| 286 |
| The second generation of the Intel x86 family
of CPU chips. The term may refer to the chip or to a PC that uses it. Introduced in 1982,
it is the successor to the 8088/8086 chips used in the first PCs. The 286 broke the
infamous one-megabyte memory barrier, but although faster than the previous generation, it
was never capable of supporting Windows and other graphics-based applications. See AT class and x86 |
|
| 3-D |
| (3 Dimensional) Refers to
objects that are constructed on three planes (X, Y and Z). A 2-D drawing program can be
used to illustrate a 3-D object; however, in order to automatically rotate the object as a
self-contained entity, a 3-D drawing program must be used. |
|
| 32-bit processing |
Refers to programs running in a 32-bit
computer. A 32-bit computer processes four bytes at a time
compared with two bytes in a 16-bit computer or one byte in an 8-bit computer. Starting
with the 386 chip, Intel CPUs have been built
with a split personality for compatibility with earlier models. They have both 16- and
32-bit modes of operation, the 32-bit mode being the native mode with more advanced
capabilities.
In 16-bit mode, or Real Mode, a program executes 16-bit instructions. In Protected Mode, a
program has access to both 16- and 32-bit instructions, the maximum amount of RAM, virtual memory and virtual machine capabilities as well as
memory protection, which keeps one program from crashing another.
DOS applications run in Real Mode, while Windows 3.1 switches back
and forth between Real Mode and Protected Mode. OS/2, UNIX, Windows 95/98, Windows NT and
other 32-bit operating systems run in Protected Mode when running 32-bit applications.
The 32-bit mode does not result in two times as much real work getting done as in 16-bit
mode, because it relates to internal processing and not every instruction or unit of data
takes advantage of the four bytes. In addition, program design as well as disk and bus
speed play important roles in a computer's performance. While the speed may improve a
little or a lot, depending on the program being run, 32-bit processing for the PC means as much a break from the past architecture as it does faster
speed. |
|
| 386 |
The third generation of the Intel x86 family
of CPU chips. The term may refer to the chip or to a PC that uses it. Introduced in late
1985, it is the successor to the 286, and although adequate for DOS applications, it is
very slow for Windows and other graphics-based programs. The 386 was the first chip in the
x86 line to provide 32-bit processing and provides both 16-bit and 32-bit modes. It added
enhanced memory management, allowing both extended and expanded (EMS) memory to be
allocated on demand. The 386 architecture has been followed in all of Intel's subsequent
486 and Pentium lines. See PC and x86.
386 CPU Technical Specs
A 32-bit multitasking microprocessor in a 132-pin PGA package. Supports
8, 16 and 32-bit data types. Has 32 32-bit registers including eight general-purpose.
Operational modes: "Real Mode" performs as a fast 8086 CPU and addresses 1MB
memory. "Protected Mode" addresses 4GB physical and 64TB virtual memory and
provides access to memory management, paging and memory protection capabilities (see 32-bit processing). "Virtual 8086 Mode" is a Protected
Mode subset that runs tasks as if each were in an individual 8086 CPU. Contains 275,000
transistors and uses 1.5 micron technology (transistor elements average 1.5 microns). |
|
| 486 |
The fourth generation of the Intel x86 family
of CPU chips. The term may refer to the chip or to a PC that uses it. Introduced in 1989,
it is the successor to the 386, and depending on clock speed, can be up to five times as
fast. It provides very acceptable performance for DOS applications, but is bare minimum
for Windows and other graphics-intensive programs. The 486 has a built-in math
coprocessor.
Later versions of the chip offered double and triple the internal speed while maintaining
the same external speeds (see DX2 and DX4).
See OverDrive CPU, PC and x86.
486 CPU Technical Specs
A 32-bit multitasking microprocessor that uses the same registers and
operational modes as the 386 (see 32-bit processing). It
obtains its speed from an internal 8KB memory cache that it quickly fills in burst mode.
The chip is housed in a 168- or 169-pin PGA package.
The 486DX chip contains 1.2 million transistors; the 486SX contains 1.1 million. Both use
1.0 micron technology (transistor elements are as small as one micron). |
|
| 586 |
| A Pentium-class chip made by a company other
than Intel. The 486 was the last numeric designation used by Intel.
What was to be the 586 became the Pentium, thus, Pentium-class chips from non-Intel
manufacturers were often designated as 586s and Pentium Pro-class chips as 686s. |
|
| 64-bit graphics accelerator |
| A display adapter that has a pathway 64 bits
wide between its on-board graphics processor and memory (video RAM). |
|
| 686 |
| A Pentium Pro-class chip made by a company
other than Intel. The 486 was the last numeric designation used by
Intel. What was to be the 586 became the Pentium, thus, Pentium-class
chips from non-Intel manufacturers are often designated as 586s and Pentium Pro-class
chips as 686s. |
|
| 8-bit color |
| Using one byte per pixel in a color image. Up
to 256 colors can be represented in the color palette. Various graphics formats are
limited to 256 colors; for example, GIF images, which are widely used on the Web, are
8-bit color. See bit depth and bit
specifications. |
|
| 802.11 |
A family of IEEE standards for wireless LANs
first introduced in 1997. The first standard to be implemented, 802.11b, specifies from 1
to 11 Mbps in the unlicensed 2.4GHz band using direct sequence spread spectrum
(DSSS)
technology. The Wireless Ethernet Compatibility Association (WECA) brands it as Wireless
Fidelity or "Wi-Fi."
Using the orthogonal FDM (OFDM) transmission method, there are two subsequent standards
that provide from 6 to 54 Mbps: 802.11a transmits in the higher 5GHz frequency range and
is not backward compatible with the slower 802.11b; 802.11g works in the same range and is
compatible.
An 802.11 system works in two modes. In "infrastructure mode," wireless devices
communicate to a wired LAN via access points. Each access point and its wireless devices
are known as a Basic Service Set (BSS). An Extended Service Set (ESS) is two or more BSSs
in the same subnet.
In "ad hoc mode," also known as "peer-to-peer mode," wireless devices
can communicate with each other directly and do not use an access point. This is an
Independent BSS (IBSS).
The speed of 802.11 systems is distance- dependent. The farther away the remote device
from the base station, the lower the speed (see chart below).
|
|
| 802.15 |
| An IEEE working group that is involved with
wireless personal area network (WPAN) standards such as Bluetooth. It is also concerned
with interoperability between wireless LANs (802.11) and WPANs. For more information,
visit http://grouper.ieee.org/groups/802/15/. See 802.11. |
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| 8080 |
| An Intel 8-bit CPU chip introduced in 1974. It
was the successor to the first commercial 8-bit microprocessor (8008) and precursor to the
x86 family. It contained 4,500 transistors and other electronic components. |
|
| 8086 |
| Introduced in 1978, the CPU chip that defines
the base architecture of Intel's x86 family (XT, AT, 386, 486, Pentium). 8086s are used in
some XT-class machines. See PC and x86. |
|
| 8087 |
| The math coprocessor for the 8086/8088. |
|
| 8088 |
The Intel CPU chip used in first-generation PCs
(XT class). It is a slower version of the 8086, chosen for migration from CP/M programs,
the predominate business applications of the early 1980s. See PC
and x86.
8088 CPU Technical Specs
Same as the 8086 CPU except that is uses an 8-bit data bus instead of a
16-bit data bus. Designed to ease conversion from 8-bit, Z80-based CP/M programs. Contains
25,000 transistors. |
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