Barebone Glossary
AGP
The AGP (Accelerated Graphics Port) slot on the computer motherboard is designed
specifically for AGP graphics cards. AGP 8X can provide 16 times the bandwidth of the
common 32-bit PCI slot. AGP is currently being phased out in favor of PCI Express on PC
systems.
Bus
The bus often refers to a data pathway (sometimes called the power pathway) which transfers
data (or power) between computer components inside a computer system or between different
computers. For example, there is a front side bus to connect the CPU to the chipset, and there
is the PCI bus to connect the chipset to PCI devices.
Chipset, covers Northbridge, Southbridge, (G)MCH, ICH
The term “chipset” (sometimes called core logic) often refers to the two main chips on the
motherboard: the Northbridge and the Southbridge. The Northbridge and Southbridge are
sometimes combined. This is called single-chip design.
The Northbridge (MCH or Memory Controller Hub in Intel applications) often refers to the chip
that handles communications between the CPU, and the AGP or PCI Express bus and the
Southbridge. The Northbridge often includes the memory controller if the memory controller is
not integrated into the CPU, and certain Northbridge chips feature integrated graphics units
(Intel calls these Northbridge chips the GMCH or Graphics & Memory Controller Hub).
The Southbridge (Intel calls it the ICH or Input/Output Controller Hub) provides connections to
I/O devices, such as the PCI bus, USB, PATA, SATA and PCI Express devices. Other
Southbridge functions include interrupt controller, real time clock, power management (ACPI
and APM), SMBus and so on. Southbridge chips are usually connected to Northbridge chips.
Codec
In motherboards, the “codec” (Compressor-Decompressor or Coder-Decoder) or “audio
codec” refers to the combined audio AD/DA (analog to digital/digital to analog) converter,
which is a required hardware for most onboard audio solutions.
CPU Socket, Socket A/478/754/939/940, LGA775
The CPU socket or slot is the interface of both the processor and the motherboard. The
processor’s socket type must match the motherboard’s CPU socket to be installed properly.
For example, an LGA775 processor must be installed on an LGA775 motherboard.
Below are the major socket types for contemporary AMD motherboards:
Socket 754
Socket 939
Current AMD Socket 754 processors include the Sempron series and older model Athlon 64
processors. AMD K8 desktop processors such as the Athlon 64, Athlon 64 FX, and Athlon 64
X2 all utilize the Socket 939 socket.
And here are the major socket types for contemporary Intel motherboards:
Socket 478
LGA775/Socket T
With the exception of certain Pentium 4 & Celeron D models still utilizing the Socket 478, most
Intel processor products like the Celeron D, Pentium 4, Pentium D, and Pentium Extreme
Edition are currently on the LGA775 socket.
DDR
DDR (Double Data Rate) SDRAM sends and receives data twice as often as common SDRAM.
This is achieved by transferring data on both the rising edge and the falling edge of a clock
cycle.
DDR2
Second generation DDR memory provides greater bandwidth and other new features such as
On-Chip Termination (OCT). 4 bits of data are moved from the memory array to the I/O buffers
(per data line) each core cycle. This can be described as 4-bit prefetch, as opposed to the
single-bit fetch in SDRAM and 2-bit prefetch with DDR SDRAM.
DIMM
The most common type of memory module is the DIMM (Dual In-Line Memory Module), which
is capable of transferring 64 bits of data per cycle.
DRAM
The memory cells of DRAM (Dynamic Random Access Memory) memory modules require
constant refreshing because they utilize both transistors and capacitors. Capacitors lose the
values they store as time elapses without refreshing.
Dual-Channel
In the memory system, this describes a motherboard/memory controller with two 64-bit wide
channels. When memory is used in dual channel mode, the bandwidth doubles - for instance,
dual channel DDR400 provides 6400MB/s (or 6.4GB/s) bandwidth as opposed to 3200MB/s
for single channel DDR400.
D-Sub
This 15-pin VGA output port finds widespread usage and is responsible for connection to CRT
monitors and LCD monitors that support analog input. Digital signals must go through
RAMDAC conversion before being sent through the D-Sub port as it is capable of only analog
input.
DVI
DVI (Digital Video Interface) is a display/monitor interface standard. There are three types DVI:
DVI-I (digital and analog), DVI-D (digital only) and DVI-A (analog only). Many current display
devices use DVI to receive video signals, such as LCD monitors and projectors. For
compatibility with these display devices, most video cards today equip the DVI port as a
standard output port.
Form factor
In computing, form factor is an industry term for the size, shape and format of computer
motherboards, power supplies, cases, add-in cards and so on. The ATX and BTX form factors
are the most prevalent form factors today.
IEEE 1394
Also known by the trademarked names of FireWire and i.LINK, IEEE 1394 is a standard for
high-speed transfer of digital information. It is one of the most popular standards for
connecting computers and other digital devices to various components and peripherals, such
as external hard disk drives, scanners and digital video camcorders.
I/O
I/O (Input / Output) often refers to the connection or interface between your computer system
and other internal or peripheral hardware devices.
LAN
A LAN (Local-Area Network) is a computer network that connects PCs, workstations or other
LANs and networks to enable data and device access and sharing. It is used to cover a small
local area such as a home, office or small group of buildings. Current LANs are most likely to
be Ethernet (wired) or Wi-Fi (wireless) based.
PATA, IDE/EIDE
ATA is the acronym for Advanced Technology Attachment, and it has become an industry
standard hard drive interface for 15 years. ATA uses a 16-bit parallel connection to make the
link between storage devices and motherboards, and is also called PATA (Parallel ATA) to
distinguish it from the newer SATA standard. In additional, ATA is also known as IDE or EIDE
(Enhanced Integrated Drive Electronics). Currently the two most popular standards for ATA
hard drives are the ATA-6 (which is also known as Ultra ATA 100 or Ultra DMA 100) and ATA
133. The maximum bandwidth for the former is 100MB/s, and 133 MB/s for the latter.
PCI
The PCI (Peripheral Component Interconnect) bus is a computer bus type used to connect
computer peripherals. Most PCI buses in a PC system work at 33MHz with a 32bit bit-width.
This allows it to deliver a bandwidth of 133MB/s.
The PCI slot (not to be mistaken with the PCI bus) has fallen out of favor in the graphics
domain and has been replaced by the AGP and PCI Express connectors.
PCI Express
PCI Express is the latest computer bus following PCI and AGP. PCI Express can come in
several physical configurations to offer a variety of maximum bandwidths. For example, the
fastest PCI Express x16 configuration is used mainly for graphics card application and
provides up to 8GB/s (bi-directional) bandwidth, or 4 times the bandwidth of AGP 8X. At the
other end of the spectrum, PCI Express x1 is typically used for other types of peripherals and
offers up to 500MB/s (bi-directional) bandwidth.
PS/2 Ports
The Personal System/2 or PS/2 was the designation for IBM's second generation of personal
computers. The PS/2 keyboard and mouse ports were introduced with it. PS/2 ports connect
the keyboard and mouse to a computer and are usually color-coded on today’s systems purple for keyboards and green for mice. Most desktop motherboards still provide PS/2 ports,
but an increasing number of keyboards and mice are using USB ports.
SATA
SATA (Serial ATA) is an interface standard for connecting hard drives to computer systems,
and is based on serial signaling technology. The advantages over PATA include longer, thinner
cables for more efficient airflow within a computer chassis, fewer pin conductors for reduced
electromagnetic interference, and lower signal voltage to minimize noise margin. The
bandwidth of SATA is also far improved over today’s PATA - the SATA 1.0 can reach a
maximum of 1.5Gb/s (150MB/s), while the latest SATA 2.5 standard can support up to 3Gb/s
(300MB/s). As a result of so many advantages, the SATA interface is gradually replacing PATA
as the mainstream hard drive interface in the personal storage market.
USB
The USB (Universal Serial Bus) port is a popular I/O interface used for connecting computers
and peripherals or other devices. It is capable of supporting up to 127 daisy-chained peripheral
devices simultaneously. The latest USB 2.0 specification can deliver 480Mbps data transfer
bandwidth.