Hardware Glossary

Terms from the PC and Computer World

Some terms or jargon related to computer hardware. Even if it still means nothing to you, it may wipe the smirk off some one who thinks they know everything.

ACPI - an advanced power and configuration interface. Latest standards allows the pc or laptop to manage its power needs efficiently. Such benefits can be powering devices fully on a need to know basis, and lowering sore power until needed.

ADSL - stands for Asymmetric Digital Subscriber Line, a broadband connection used over ISDN and dial up connections, similar to cable modems.

AGP - stands for accelerated graphics port. A expansion slot on the motherboard usually brown and used to provide high performance graphics via AGP cards, standard is 2x newer 4x standard allows peak transfer speeds of 512MBps for 2x, and 1.1GBps for the 4x.

AIT - Advanced Intelligent Tape, this a Sony magnetic tape using the 8mm cassette standard, these cassettes can hold up to 100GB.

ATA - means AT Attachment, this term is the signal and protocol for IDE devices. Newer hard drives run at ATA 100, or ATA 66, ATA 33 has been phased out, also known as Ultra66 & 100. This describes the bandwidth of the disc.

ATAPI - a packet attachment interface which is used to extend the EIDE interface used with CD-ROMS and similar devices.

BIOS - meaning basic input/output system. This software is stored on board and is used to boot the system and carry out memory tests and what devices are attached.

BIT -  the smallest unit of data possible, it's values are 1 & 0 (binary) they are stored in capacitors on memory chips using electrical currents. These are often abbreviated ie 5kbps = 5,000 bits per second.

BURN-PROOF / UNDERUN - This technology is included with some cd writers, the technology controls the data stream going to the writer and avoids errors and underun problems which on writers with out BURN- PROOF will be useless and wont read in other drives basically another coaster. Very good if you can afford the extra do it, it will save you discs and time in the long run. Also depending on the size of the buffer you can to a task or two at the same time as burning.

BYTE - 8 bits used to make up one byte, this is where it can be 'tricky' as the binary system is used which makes a kilobyte = 1,024 byte. A Megabyte (MB) is 1,048,576 bytes. This mistake is often noted by newer users when more ram or hard drives are added as 128mb of ram will be 131,   kilobytes as 1mb is 1,048,576. It doesn't make a real difference to us the users but is worth knowing.

CACHE - this is a temporary area used to speed up processes. A good example is web browsers they will keep a log of recently used pages so that when you re-visit, they will load quicker.

CLUSTER - The smallest amount of space that a file can occupy on a disc, with hard discs, the larger the size of the disc the larger the cluster will be.

CMOS - stands for complementary metal oxide semiconductor. Although more well known for the battery powered chip on motherboards which stores the system and clock configurations.

COMPRESSION - This is reducing the size of a file so it can be stored in a smaller space. A common compression utility in Winzip. 

CPU - central processing unit, a microprocessor which is basically the brains of the computer performing many instructions a second to carry, fetch and compute.

DAT - stands for Digital Audio Tape, this is a magnetic tape using 4mm cartridges, often used in DAT drives for backups. Didn't take of as planned used for backup tape drives and was mainly used by musicians and sound studios. There are 4 medias DDs-1 - 4 which range at 2GB, 4GB, 12GB, 20GB. 

DATA RATE - This is the amount of data a hard disc or device is capable of saving / transferring per second.

DIMM - dual in line memory module, a memory board referred to as ram. Similar to SIMMS but newer and effectively double sided, can be added singularly and is common format at the moment. comes with a 168 pin connector.

DMA - stands for direct memory access, this is the process that sis the retrieval of data from a hard drive which writes it into the memory with out requiring the cpu this frees up tasks and resources.

DRAM - a common and cheapest form of memory, which uses a capacitor and transistor to store one bit of data, it is similar to ram and is volatile so once power is removed it loses its memory.

DVD - digital versatile disc, but now also referred to as digital video disc following popular use in storing movies. There are several different formats at present ranging from 2.6GB - 17GB once a agreed format has been settled prices of media and recording devices will fall to realistic levels.

EPP/ECP - enhanced parallel port / extended capabilities, uses improved parallel port to give rates of over 2MB/s as well as bi directional duties. Bi-directional is mainly referred to in printing, basically allows the printer to communicate with the port backwards and forwards to inform of errors and such like.

FAT - file allocation table, these are held on floppy's or hard disks and communicate with the operating system where the data is stored. Using 16 bit addresses (FAT 16) it can only support disks up to 2GB, the FAT32 can handle sizes from 2GB - 2TB (terabytes)

FireWire - this is a very quick interface for use with external devices. Sometimes also known as IEEE 1394 or iLink, this format can support up to 63 devices and speeds of around 400Mbps. It is more expensive than USB, and at the moment used primarily for digital cameras and PDA's etc and where a high transfer rate is beneficial.

GIGABYTE - The standard unit of measurement for hard disk sizes, a gigabyte (GB) is roughly 1000 megabytes. (MB)

HARDWARE - A term used to describe every item of a computer that can be physically touched.

IDE - stands for integrated drive electronics, the commonest way of connecting hard drives and over devices to the PC. The units come with built in boards etc so no need for adapters as with SCSI devices you can just connect and power up.

IRQ - interrupt request signal, these are used by devices to basically interrupt the cpu to get its attention so that the cpu can read the instruction and carry out the task.

ISDN - stands for Integrated Services Digital Network, this is a digital phone line used to enhance connection speed the ISDN lines transmit at 64 kps, or 128 kbs if you use two lines. The maximum speed from a standard line is 56 kbs. For ISDN you will need a digital line and a ISDN adapter which does the job of the modem for the digital line.

KILOBYTE - a kilobyte is 1024 bytes but often referred to 1000 bytes of data. This is sometimes mistaken by users who think they have been done out of some hard drive space etc when really its 1024 not 1000.

LBA - this means Logical Block Addressing, used in hard drives capacity's.

LOGICAL DRIVE - a sub- partition of an extended partition on a hard disk.

SMEGABYTE - a 1000 kilobytes is a MB

MFM - A old dated hard drive standard, special controller card was required.

MIDI - stands for musical instrument digital interface, this is the standard for connecting musical instrument like a midi keyboard to your PC

MILLISECOND - This is the speed that hard drives access is timed, 1 millisecond is 1 thousandth of a second.

MODEM - stands for MOdulator - DEModulator this is the device that allows your computer to communicate with your phone line and then the Internet.

PARALLEL PORT - this is the 25 pin 'D' shaped port on your pc it is used mainly for connecting printers, it offers a fairly slow transfer rate by many standards but is used for printing and attaching scanners primarily.

PCI - peripheral component interconnect, this is the commonest interface for attaching internal components to your system these are the white slots for modems, graphic cards and such like.

POST - power on self test, this is the very first action the PC will run when it is switched on. It will check that all devices such as memory, graphics, drives etc are working before it attempts booting. If it finds any errors it will sound a series of beeps, the standard one beep at booting is a indication that it has found nothing amiss and will boot.

RAM - (Random Access Memory), this is the memory of the computer that will store data while it processes and performs task before patching and transferring chosen data to be written to the hard drive. Measured in nano seconds, the more ram in your system the quicker it will be able to run faster most noticeably when doing multitasking as the system wont need to request the hard rive so often. Data will be lost once the system is switched off.

RIMM - this stands for Rambus inline memory (RDRAM), this is latest incarnation of system memory and is capable of running at 800mhz compared to the 66/100/133 or so standards currently. At the moment it can be expensive when compared and is mainly suitable for high demanding applications. The Rambus technology is used in the Pentium 4 based systems.

ROM - Read Only Memory, this is data that can only be read and not written to such as cdr.

SCSI - small computer systems interface, this is another way to connect hard drives and cd writer/dvd drives to PC's. It is a more expensive option to IDE, you will need a SCSI adapter to connect the devices to. They are normally used in larger systems and servers and the devices can be daisy chained together, they are normally faster than IDE and can support higher transfer rates.

SDRAM - synchronous DRAM, this memory matches itself in synch with the speed of the cpu bus. At the moment 133mhz is the fastest cost effective standard. You will need to insure that your board and cpu are compatible to get the full speed out of your ram, most have backward compatibility.

SIMM - single inline memory module, this is an older type of memory board similar to dimms etc, it has 72 pins and has to be used in pairs used mainly in early Pentiums and some boards still carry some simms, you can not mix simms with dimms.

TERRABYTE - a Terrabyte (TB) is a term used to describe 1000 Gigabytes (GB)

TFT - thin film transistor, these are a high quality crystal display and are used in laptop screens and PDA's.

UDMA - ultra DMA is the latest EIDE controllers that support transfer rates of 33/66/100Mbps.

USB - Universal Serial Bus, this is the common plug & play and also hot plugging interface. USB supports up to 127 devices and speeds of around 12Mbps. USB 2.0 is due to ship with most newer motherboards shortly this will allow faster speeds of transfer, we are unsure if all devices will be supported, cables for direct cable connection form USB to 2.0 standard seem unlikely.