A

B

Bank:

The DRAMs on a module are organized into a number of Banks that can be accessed simultaneously.

C

CAS Latency:

See latency

CAS-2::

Wait 2 clock cycles after the Column Address before the data appears. CAS-3, wait 3 clock cycles.

Compact Flash:

A small flash memory module. The memory chips are enclosed in a plastic case and hold data after they are removed from the system. The most common uses for these are in Camera's , Computers and Music Players.

Computer:

An electronic device that stores, retrieves, and processes data, and can be programmed with instructions. A computer is composed of hardware and software, and can exist in a variety of sizes and configurations. 

Client/server network:

A configuration where all people store their files on a central computer, and files are accessed directly from where they are stored on the central computer. The central computer is the server, and the client is a workstation.

Caching:

Where data is stored in memory, rather than on disk, to decrease access time.

CPU:

Abbreviation of central processing unit, and pronounced as separate letters. The CPU is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.

On large machines, CPUs require one or more printed circuit boards. On personal computers and small workstations, the CPU is housed in a single chip called a microprocessor.

Two typical components of a CPU are:

• The arithmetic logic unit (ALU), which performs arithmetic and logical operations.

• The control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.

D

DDR:

Double data rate is a type of SDRAM in which data is sent on both the rising and falling edges of clock cycles in a data burst. It is usually referred to as DDR as opposed to DDR SDRAM.

DDR2:

Like DDR, DDR2 is a type of SDRAM in which data is sent on both the rising and falling edges of clock cycles in a data burst. DDR2 is the next evolutionary step in the DDR infrastructure and has additional features built into it to allow for increased system performance.

DDR3:

Double Data Rate, third generation.

DIMM:

Dual inline memory module. A module with signal and power pins on both sides of the board (front and back).

DMA:

Short for Direct Memory Access, DMA is the transferring of data from one storage device to memory to another device without using the CPU. Because DMA is freeing up the usage of the processor, DMA tends to be faster than PIO (Programmed Input/Output) mode.

DRAM:

Dynamic random access memory. A type of memory component used to store information in a computer system. "Dynamic" means the DRAMs need a constant "refresh" (pulse of current through all of the memory cells) to keep the stored information. (See also RAM and SRAM.)

Dual Rank:

Defines 2 sets of DRAM chips (on a module) each comprised of 8 byte wide (64 bits) data, or 9 bytes (72 bits) with ECC. All devices in a Rank are connected by a single Chip-Select. The actual memory size is not defined. Normally a module will have one rank per PWB side.

E

ECC:

Error correcting code. Logic designed to detect and correct memory errors.

EDO:

Extended data out. An asynchronous DRAM operating mode that improves access times compared to fast page mode (FPM) DRAMs.

Email:

Electronic messages, typically addressed as person to person correspondence, that are transmitted between computers and across networks.

F

Flash memory:

Flash memory is a non-volatile memory device that retains its data after the power is removed.

Firewall:

An electronic boundary that prevents unauthorized users and/or packets of data or information (e.g., files and programs) from accessing a protected system. 

FPM:

Sometimes abbreviated as FP or FPM, and also known as Fast page Mode, fast page is a type of DRAM memory that reduces the power consumption and has a faster access because of the elimination of the column address setup time during the page cycle. 

FSB:

Front side bus – the physical interface between processor and main memory in Intel chipsets.
The main highway for data in a PC. It connects the processor, chip set, DRAM, and AGP socket. FSB is described in terms of its width in bits and its speed in MHz.

FB-DIMM:

Fully-Buffered DIMM [utilizes JEDEC-standard DDR2 SDRAM]

Rank:

Defines a set of DRAM chips (on a module) comprising 8 byte wide (64 bits) data, or 9 bytes (72 bits) with ECC. All devices in a Rank are connected by a single Chip-Select. The actual memory size is not defined. Single-sided memory modules are always Single-Rank. Double-sided unbuffered DIMMs and SODIMMs are always Dual-Rank. Server DIMMs may have up to 4 ranks.

G

Gigabyte:

Amount of memory equal to 1024 Megabytes (1,073,741,824 bytes) of information. Abbreviated GB.

GDDR:

Graphics DDR I/II/III/IV; GDDR1, GDDR2, GDDR3, GDDR4 - 1.25GHz Clock for GDDR4

H

Hard Drive:

The mechanism that reads and writes data on a hard disk . Hard disk drives (HDDs) for PCs generally have seek times of about 12 milliseconds or less. Many disk drives improve their performance through a technique called caching . There are several interface standards for passing data between a hard disk and a computer . The most common are IDE and SCSI . Hard disk drives are sometimes called Winchester drives, Winchester being the name of one of the first popular hard disk drive technologies developed by IBM in 1973. Whats Inside a Hard Drive?

I

ISP (Internet Service Provider):

An entity that provides commercial access to the Internet. These can range in size from someone operating dial-up access with a 56 kilobit line and several dozens of customers to providers with multiple pops in multiple cities and substantial backbones and thousands or even tens of thousands of customers. 

IDE:

A type of hard drive interface. Provided as standard on Risc PC motherboards. It can have up to two physical drives, configured as 'master' and 'slave'.

ICMP:

Short for Internet Control Message Protocol, an extension to the Internet Protocol (IP). ICMP supports packets containing error, control, and informational messages. The PING command, for example, uses ICMP to test an Internet connection.

J

K

L

Latency:

The amount of time in nanoseconds (often measured in clock cycles) between a request to read the memory, and when it is actually output. SDRAMs are typically referred to as CL2 or CL3, with CL2 parts being faster.

Local memory:

1. When referring to a computer with more than one computer processor, local memory refers to a portion of memory that is designated to a specific computer processor that no other processor is capable of accessing.
2. Local memory is also used to describe a portion of memory that a software program or utility only has access to once obtained.

LAN (Local Area Network):

Communications network connecting computers by wire, cable, or fiber optics link. Usually serves parts of an organization located close to one another, generally in the same building or within 2 miles of one another. Allows users to share software, hardware and data.

M

Megabyte:

Amount of memory equal to 1,048,576 bytes of information. (Abbreviated MB.)

Memory capacity:

The maximum or minimum amount of memory a computer or hardware device is capable of having or the required amount of memory required for a program to run.

For example, a computer software program may list the requirements:

Recommend 32MB of memory
Minimum 16MB of memory

In the above recommendations, the developer of the program recommends, for optimal performance, that the computer have 32MB of memory. However, it is capable of running with 16MB of memory, but may lack in performance.

Motherboard:

The main printed circuit board in a computer that carries the system buses. It is equipped with sockets to which all processors, memory modules, plug-in cards, daughterboards, or peripheral devices are connected.

MP3:

The name of the file extension and also the name of the type of file for MPEG, audio layer 3.

Layer 3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the compression of audio signals. Layer 3 uses perceptual audio coding and psychoacoustic compression to remove all superfluous information (more specifically, the redundant and irrelevant parts of a sound signal. The stuff the human ear doesn't hear anyway). It also adds a MDCT (Modified Discrete Cosine Transform) that implements a filter bank, increasing the frequency resolution 18 times higher than that of layer 2.

The result in real terms is layer 3 shrinks the original sound data from a CD (with a bit rate of 1411.2 kilobits per one second of stereo music) by a factor of 12 (down to 112-128kbps) without sacrificing sound quality.

Because MP3 files are small, they can easily be transferred across the Internet.

Module:

1. In software, a module is a part of a program. Programs are composed of one or more independently developed modules that are not combined until the program is linked. A single module can contain one or several routines.

2. In hardware, a module is a self-contained component.

N

O

P

Portable Hard drive:

A Hard Drive that is in a protective case that you can connect to your computer via a Firewire or USB port. Some Portable Hard Drives may need 2 USB ports to work, one for power and the oter for data.

Printer:

A device that translates signals from a computer into words and images onto paper in black and white or color. Printer types include dot matrix, ink jet, laser, impact, fax, and pen and ink devices.

PIO(Programmed Input/Output):

A method of transferring data from a device to another device utilizing the computer processor and not the memory or DMA. Because PIO modes utilize the computer processor, using PIO is slower than DMA.

Packets:

A packet is the fundamental unit of information carriage in all modern computer networks. The term datagram is sometimes also used, and in some contexts its meaning is subtly different from packet.

PING:

Ping is a basic Internet program that lets you verify that a particular Internet address exists and can accept requests. The verb ping means the act of using the ping utility or command. Ping is used diagnostically to ensure that a host computer you are trying to reach is actually operating.

Processor:

See CPU

Q

Quad Rank:

Defines 4 sets of DRAM chips (on a module) each comprised of 8 byte wide (64 bits) data, or 9 bytes (72 bits) with ECC. All devices in a Rank are connected by a single Chip-Select. The actual memory size is not defined. Normally a module will have two ranks per PWB side.

R

RAM:

Random access memory. A data storage device for which the order of access to different locations does not affect the speed of access, except for bursts. Data is typically stored in RAM temporarily for use by the process or while the computer is operating. FPM, EDO, SDRAM, DDR, etc. are all types of RAM.

Registered:

Registers delay memory information for one clock cycle to ensure all communication from the chipset is collected by the clock edge, providing a controlled delay on heavily loaded memories.

RIMM:

Rambus inline memory modules used for Rambus DRAM.

Router:

A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP’s network. Routers are located at gateways, the places where two or more networks connect.

Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.

Very little filtering of data is done through routers.

RDRAM:

Short for Rambus Dynamic Random Access Memory, RDRAM was developed by Rambus and is a technology of memory that offers a 1.6 GB/s of theoretical memory bandwidth, offers improved memory access at a slightly higher cost when compared to SDRAM.

Rank:

Defines a set of DRAM chips (on a module) comprising 8 byte wide (64 bits) data, or 9 bytes (72 bits) with ECC. All devices in a Rank are connected by a single Chip-Select. The actual memory size is not defined. Single-sided memory modules are always Single-Rank. Double-sided unbuffered DIMMs and SODIMMs are always Dual-Rank. Server DIMMs may have up to 4 ranks.

S

SD Memory Cards:

The SD Memory Card is small, easy-to-use card that offers users many advantages. It links many kinds of digital equipment such as digital cameras, DV cameras, PDAs, Phones, etc.

SDRAM:

Synchronous dynamic random access memory delivers bursts of data at high speeds using a synchronous interface. Its is actually SDR SDRAM (single data rate SDRAM) but is usually used to referred to as just "SDRAM."

Server:

See Client/server network

SIMM:

Single inline memory module. A high-density DRAM package alternative consisting of several components connected to a single printed circuit board.

SRAM:

An integrated circuit similar to a DRAM (dynamic random access memory) with the exception that the memory does not need to be refreshed. Unlike volatile memory (ie, DRAM), SRAM retains its contents even when the main current is turned off.

SCSI:

Stands for small computer system interface. A standard that allows multiple devices to be connected in daisy-chain fashion.

SDRAM:

Short for Synchronous DRAM, SDRAM is a type of DIMM memory that synchronizes itself with the computers system clock to provide a synchronization between the memory and the computer processor.

SO:

Small Outline (Memory Module), as in SO-DIMM.

T

U

USB / USB 1.0:

Short for Universal Serial Bus, an external bus standard that supports data transfer rates of 12 Mbps . A single USB port can be used to connect up to 127 peripheral devices , such as mice , modems , and keyboards . USB also supports Plug-and-Play installation and hot plugging

USB 2.0:

Hi-Speed USB , USB 2.0 is an external bus that supports data rates up to 480 Mbps . USB 2.0 is an extension of USB 1.1 . USB 2.0 is fully compatible with USB 1.1 and uses the same cables and connectors.

V

Virtual Memory:

Virtual memory is a method of using the computer hard disk drive to provide extra memory for the computer. Segments of memory are stored on the hard disk drive known as pages. When a segment of memory is requested that is not in memory it is moved from the virtual memory to an actual memory address.

W

WAN (Wide Area Network):

Take two local area networks, hook them together, and you've got a WAN. Wide area networks can be made up of interconnected smaller networks spread throughout a building, a state, or the entire globe.

X

Y

Z