Current that cycles backand forth rather than traveling in only one direction. In the United States, the AC voltagefrom a standard wall outlet is normally between110 and 115V. In Europe, the standard AC voltagefrom a wall outlet is 220V.
alternating current (AC)
A unit of measurement forelectrical current.
ampere or amp (A)
The most common form factor for PC systemspresently in use, originally introduced by Intel in1995.
A power supply that providesa 12V power cord with a 4-pin connector to beused by the auxiliary 4-pin power connector onmotherboards used to provide extra power forprocessors.
ATX12V power supply
Temporary reductions in voltage, whichcan sometimes cause data loss. Also called sags.
A form factorused by motherboards and computer cases that was expected to replace ATX. It has higher qualityfans, is designed for better air flow, and has improved structural support for the motherboard.
BTX (Balanced Technology Extended)
An electronic device that can maintain anelectrical charge for a period of time and is used tosmooth out the flow of electrical current.
The maximum voltage allowedthrough a surge suppressor, such as 175 or330 volts.
A type of case used in low-end desktopsystems. Compact cases, Also called low-profile orslimline cases, follow either the NLX, LPX, orMini LPX form factor. They are likely to havefewer drive bays, but they generally still providefor some expansion.
A surge protector designed towork with the telephone line to a modem.
data line protector
A computer case that sits flat on adesktop doing double duty as a monitor stand.
Adapter cards designed to discoverand report computer errors and conflicts at POSTtime (before the computer boots up), often bydisplaying a number on the card.
An electronic device that allows electricity toflow in only one direction. Used in a rectifier circuit.
A switch on acircuit board or other device that can be set to onor off to hold configuration or setup information.
DIP (dual inline package) switch
Current that travels in only onedirection (the type of electricity provided bybatteries).
direct current (DC)
A magnetic fieldproduced as a side effect from the flow ofelectricity. can cause corrupted data in datalines that are not properly shielded.
electromagnetic interference (EMI)
Another name forstatic electricity, which can damage chips anddestroy motherboards, even though it might not befelt or seen with the naked eye.
electrostatic discharge (ESD)
A component in acomputer or device that can be replaced with anew component without sending the computer ordevice back to the manufacturer. Examples: powersupply, DIMM, motherboard, floppy disk drive.
field replaceable unit (FRU)
A version of the ATX form factor thatallows for maximum flexibility in the size andshape of cases and motherboards. idealfor small, custom systems.
A set of specifications on the size, shape,and configuration of a computer hardwarecomponent such as a case, power supply, ormotherboard.
A strap you wear around your wristthat is attached to the computer case, ground mat,or another ground so that ESD is discharged fromyour body before you touch sensitive componentsinside a computer. Also called static strap, groundstrap, ESD bracelet.
A UPS connected to a computer byway of a USB or serial cable so that software onthe computer can monitor and control the UPS.
intelligent or smart UPS
A device that converts DC to AC.
A measure of work or energy. One joule ofenergy produces one watt of power for onesecond.
A device that regulates, orconditions power, providing continuous voltageduring brownouts and spikes.
A version of the ATX form factor. addresses some new technologies thatwere developed after the original introductionof ATX.
The most versatile and popular computercase, which is midrange in size and generally hasaround six expansion slots and four drive bays;provides moderate potential for expansion.
A device used to measure the variouscomponents of an electrical circuit. The mostcommon measurements are voltage, current, andresistance.
A low-end form factor that is similar to LPX butprovides greater support for current and emergingprocessor technologies. was designed for flexibility and efficiency of space.
Cases used for notebook computers,which are proprietary in design, leave almost noroom for expansion, and include a thermometerthat controls the case fan.
Running a processor at a higherfrequency than is recommended by themanufacturer, which can result in an unstablesystem, but is a popular thing to do when acomputer is used for gaming.
Power connection on an ATX or BTXmotherboard, which can have 20 or 24 pins.
A self-diagnostic programused to perform a simple test of the CPU, RAM,and various I/O devices. is performedby startup BIOS when the computer is first turnedon, and is stored in ROM-BIOS.
POST (power-on self test)
A line conditioner that regulates,or conditions, power, providing continuous voltageduring brownouts.
A box inside the computer case thatsupplies power to the motherboard and otherinstalled devices. provide 3.3, 5, and12 volts DC.
A device that can test theoutput of each power cord coming from a powersupply.power supply
power supply tester
Interferenceproduced by a magnetic field that is a side effect ofelectricity and is in the radio frequency range.
radio frequency interference (RFI)
An electrical device that converts AC to DC.A PC power supply contains a rectifier.
An electronic device that resists or opposesthe flow of electricity. can be used toreduce the amount of electricity being supplied toan electronic component.
A card that plugs into a motherboard andallows for expansion cards to be mounted parallelto the motherboard. Expansion cards are pluggedinto slots
A button or switch on an ATX or BTXsystem that allows an OS to power down thesystem and a feature that allows for activity suchas a keystroke or network activity to power up thesystem. Also called soft power.
Temporary surges in voltage, which candamage electrical components. Also called swells.
A device or power strip designed toprotect electronic equipment from power surgesand spikes.
The largest type of personal computercase. Tower cases stand vertically and can be as high as two feet tall. They have more drive baysand are a good choice for computer users whoanticipate making significant upgrades.
A device that changes the ratio ofcurrent to voltage.
A devicedesigned to provide a backup power supply duringa power failure. Basically, a batterybackup system with an ultrafast sensing device.
UPS (uninterruptible power supply)
A measure of potential difference in anelectrical circuit.
A switch on a computer powersupply used to set voltage to 115 V or 230 V.
voltage selector switch
The unit used to measure power.
A 32-bit wide busstandard developed specifically for video cards
Accelerated Graphics Port (AGP)
The primary partition on the harddrive that boots the OS.
A specification for asmall slot on a motherboard to accommodate anaudio or modem riser card. A controller on the motherboard contains some of the logic for theaudio or modem functionality.
audio/modem riser (AMR)
An operating system programresponsible for managing the process of loadingthe OS during the boot.
The first sector of a floppy disk or harddrive volume; it contains information about thedisk or volume. Also called boot sector.
The process of starting up a computer andloading an operating system.
The Vista program file responsible forbeginning the process of loading and startingVista. The program file has no file extension and isstored in the root directory of the system partition(which, most likely, is drive C:).
The battery on the motherboard usedto power the CMOS chip when the computer isunplugged.
A specification for a small expansion slot on amotherboard that accommodates a small audio,modem, or network riser card.
communication and networking riser (CNR)
A technology by ATI Technologies thatallows for multiple video cards to be installed inthe same system. Compare to SLI (Scalable LinkInterface).
switch on acircuit board or other device that can be set to onor off to hold configuration or setup information.
DIP (dual inline package) switch
A group of pins on amotherboard that connect to wires that areconnected to the front panel of the computer case.
front panel header
Restart the computer by turning off thepower or by pressing the Reset button.
hard or cold boot
A plate installed on the rear of a computercase that provides holes for I/O ports coming offthe motherboard.
Two wires that stick up side by side on themotherboard or other device and are used to holdconfiguration information. is considered closed if a cover is over the wires, andopen if the cover is missing.
A feature of a CPU socketwhereby pads, called lands, are used to makecontact in uniform rows over the socket.
land grid array (LGA)
The first sector on a harddrive, which contains the partition table and aprogram the BIOS uses to boot an OS from thedrive.
Master Boot Record (MBR)
That portion of the chipset hub thatconnects faster I/O buses (for example, AGP buses)to the system bus.
In Windows 2000/XP, the OSloader used on Intel systems.
Ntldr (NT Loader)
Ports that are directly on themotherboard, such as a built-in keyboard port oron-board network port.
A table at the beginning of the harddrive that contains information about eachpartition on the drive. is contained in the Master Boot Record.
On a disk surface one segment of a track,which almost always contains 512 bytes of data.
A technology byNVIDIA that allows for multiple video cards to beinstalled in the same system.
SLI (Scalable Link Interface)
To restart a PC without turning off thepower, for example, in Windows XP, by clickingStart, Turn Off Computer, and Restart.
soft or warm boot
That portion of the chipset hub thatconnects slower I/O buses (for example, a PCI bus)to the system bus.
A feature of a CPUsocket whereby the pins are staggered over the socket in order to squeeze more pins into a small space.
staggered pin grid array (SPGA)
Round plastic or metal pegs that separatethe motherboard from the case, so thatcomponents on the back of the motherboard donot touch the case.
One of many concentric circles on the surfaceof a hard drive or floppy disk.
A power-on password required toview or edit BIOS setup or use the computer. Thepassword is set on a BIOS setup screen.
A clock tick in which nothing happens,used to ensure that the microprocessor isn’t gettingahead of slower components. Too many can slow down a system.
A socket that usesa small lever to apply even force when you installthe microchip into the socket.
zero insertion force (ZIF) socket
A processor instruction set by AMDdesigned to improve performance with 3Dgraphics and other multimedia data.
Specification developed by Intel, Compaq,Phoenix, Microsoft, and Toshiba to controlpower on computers and other devices.
ACPI (Advanced Configuration and Power Interface)
The portion of a processor’sinternal bus that connects the processor to theinternal memory cache. operates at amuch higher frequency than the front side bus.
back-side bus (BSB)
A Windows error that displaysagainst a blue screen and causes the system to halt.Also called a stop error.
blue screen errors
Defined by ACPI and used by a processor to stop its internal operations to conserve power.Using C0 though C6 states, the processor shuts down various internal components (for example,the core clock, buffers, cache, and core voltage).
A fan inside a computer case used to drawair out of or into the case.
A technology used by Intel whereby theprocessor, chipset, and wireless network adapterare all interconnected as a unit which improveslaptop performance.
A round air duct that helpsto pull and direct fresh air from outside acomputer case to the cooler and processor.
chassis air guide (CAG)
A feature of AMD processors thatlowers power requirements and helps keep asystem quiet.
A combination cooling fan and heat sinkmounted on the top or side of a processor to keepit cool.
The most common type ofsystem memory, it requires refreshing every fewmilliseconds.
dynamic RAM (DRAM)
A processor package that contains two coreprocessors, thus supporting four instructions at once.
Aprocessor feature used by Intel that steps downprocessor frequency when the processor is idle toconserve power and lower heat.
Enhanced Intel SpeedStep Technology (EIST)
A processor security feature byIntel that prevents software from executing orreproducing itself if it appears to be malicious.
Execute Disable Bit
The bus between the CPU and memoryon the motherboard. The bus frequency indocumentation is called the system speed, such as400 MHz. Also called the memory bus, front-sidebus, local bus, or host bus.
A piece of metal, with cooling fins, thatcan be attached to or mounted on an integratedchip (such as the CPU) to dissipate heat.
The Intel technology that allows each logical processor within the processor package to handle an individual thread in parallel with other threads being handled by other processors within the package.
The bus inside the CPU that is used for communication between the CPU’s internal components.
Memory on the processor die used as a cache to improve processor performance.
Level 1 (L1) cache
Memory in the processor package,but not on the processor die. The memory is used as a cache or buffer to improve processor performance.
Level 2 (L2) cache
Cache memory further from the processor core than Level 2 cache, but still in the processor package.
Level 3 (L3) cache
A method to cool overclocked processors that uses a small pump inside the computer case and tubes that move water or other liquid around components and then away from them to a place where fans can cool the liquid.
liquid cooling system
A small amount of faster RAM that stores recently retrieved data, in anticipation of what the CPU will request next, thus speeding up access.
A programming instruction that can be executed by a CPU without breaking the instruction down into simpler instructions.
Multimedia instructions built into Intel processors to add functionality such as better processing of multimedia, SIMD support, and increased cache.
MMX (Multimedia Extensions)
A processor technology where by the processor housing contains two or more processor cores that operate at the same frequency, but independently of each other.
The factor by which the bus speed or frequency is multiplied to get the CPU clock speed.
A system that containsmore than one processor.
A processor package that contains eight cores and supports 16 instructions at once.
Standards for processors established byACPI that define how processor frequency and voltage can be lowered to conserve power when the processor is not in use.
An AMD technology that increases performance and lowers power requirements for processors.
The frequency at which the CPU operates. Usually expressed in GHz.
A processor package that contains fourcores and supports eight instructions at once.
The ACPI power saving mode where the hard drive and monitor are turned off and everything else runs normally.
The ACPI power saving mode where the hard drive, monitor, and processor are turned off.
The ACPI power saving mode where everything is shut down except RAM and enough of the system to respond to a wake-up call such aspressing the keyboard. Also called sleep mode orstandby mode.
The ACPI power saving mode where everything in RAM is copied to a file on the hard drive and the system is shut down. When the system is turned on, the file is used to restore the system to its state before shut down. Also called hibernation.
A CPU technology that allows the CPU to receive a single instruction and then execute it on multiple pieces of data. also improves on 3D graphics
SSE (Streaming SIMD Extension)
An improved version of SSE that has a larger instruction set.
A CPU instruction set that improved on the earlier SSE2 instruction set.
A CPU instruction set that improved 3D imaging for gaming and improved performancewith data mining applications over the earlier SSE3 instruction set.
RAM chips that retain information without the need for refreshing, as long as the computer’s power is on. They are more expensive than traditional DRAM.
static RAM (SRAM)
A cream like substance that is placed between the bottom of the cooler hea tsink and the top of the processor to eliminate airpockets and to help to draw heat off the processor.
A processor package that contains three core processors, thus supporting six instructions at once.