J-M

jumper

A small connector used to connect two pins together on a circuit board for the purpose of configuration.

KB (Kilobyte)

1,024 bytes.

Kbps (Kilobits Per Second)

A measurement of data transfer rate. One kilobit per second is equivalent to 1,000 bits per second.

key

1. A notch or other physical feature that prevents a devices from being inserted into a slot the wrong way 2. The top level portions of the Windows registry.

knowledge base

A collection of all technical information about a manufacturer’s or developer’s products. Almost always searchable on the Web.

LAN (Local Area Network)

A network of computers that are typically connected in a central location, such as a building. In a LAN, computers are connected by wires or other media and share common resources, such as printers, files, and modems.

laptop

A small portable computer. Although laptops are generally considered larger than notebooks, the two terms are often used interchangeably, including in this book.

LBA (Logical Block Addressing)

An enhanced BIOS translation method used for IDE and SCSI disk drives that allows accessibility beyond the 504MB limit imposed by traditional IDE. LBA is a way of addressing hard drives by assigning numbers to each sector on the drive. These numbers run sequentially, with zero representing the first sector. Originally used with SCSI drives, IDE drives began to support LBA with the advent of larger (over 504MB) IDE drives. Basically, it is a translation of the cylinder, head, and sector specifications of a drive into addresses that can be used by a ‘translating’ BIOS.

LCD (Liquid Crystal Display)

A technology for flat screen displays that uses polarized sheets and liquid crystals to produce images. LCD technology was originally used for laptop computers and watches, but is becoming very popular for desktop computers.

LED (Light-Emitting Diode)

A highly efficient, long-lasting light that illuminates when electrical current passes through it. Most LEDs are usually a monochromatic red. Benefits of LEDs include ability to display images, low power requirements, long life, and high efficiency. However, they require more power than LCDs.

legacy

Of or pertaining to any hardware using standards older than the computer on which they are to run. Also refers to versions of software that have been replaced by a newer version and data files created on such software.

load

Automatically copy files from disk into memory. When Windows or a program starts, it’s actually loading into memory.

lockup

Situation in which the computer stops responding. The screen image and pointer freeze, keyboard lights get stuck, and hard drive activity stops.

LSA (Local Security Authority)

The LSA is a key component of the logon process in both Windows NT and Windows 2000. For example, in Windows 2000, the LSA validates users for both local and remote logons.

LVD (Low-Voltage Differential)

An Ultra2 subset of the SCSI-3 standard, LVD increases the maximum burst transfer rates to 80Mbytes/sec, which is a requirement for multiple drive applications. Such increases in bandwidth means optimal performance for server environments where rapid response is required. LVD uses less power (3.3V DC) than high-voltage differentials (5.0V DC).

malware

Programs that can cause various problems on a computer or can steal your personal data.

MAN (Metropolitan Area Network)

A network that is smaller than a WAN, but larger than a LAN. It is usually confined to a city block or a college campus.

map a network drive

Assigning a drive letter to a folder or drive partition on a remote computer on the network.

MAPI (Messaging Application Programming Interface)

A Microsoft application programming interface that provides the ability to send e-mail and attachments from within programs such as Word, Excel, PowerPoint, and Access.

MAU (Multistation Access Unit)

A special hub used in a Token Ring network that is used to connect computers for a star topology network while maintaining Token Ring capabilities. It is also known as MSAU.

MB (Megabyte)

1,024 kilobytes or 1,048,576 bytes.

MBR (Master Boot Record)

The MBR is the first sector on a hard drive. A small program on the MBR contains information about the partitions, indicating which one is bootable, in case there are more than one.

MCA (Micro Channel Architecture)

A proprietary 32-bit expansion bus developed by IBM for its PS/2 computers.

MDA (Monochrome Display Adapter)

A standard for monochrome adapters introduced by IBM. Monochrome is only capable of displaying text.

Me

Microsoft Windows Millennium Edition. Microsoft uses the lower-case “e,” so we do too.

media

Disks, flash memory, or other materials used for data storage.

memory

Chip assemblies that store data for very quick recall. The main memory in a computer requires constant power to be able to hold data. Every task performed by a computer requires the program and data to be loaded into memory. Information that is held in memory can be quickly accessed by the computer’s CPU without the need to read the data preceding the required information. Synonym: random access memory (RAM).

MFD (Multifunction Device)

Any device that is capable of multiple functions. For example, with printers, you can have a laser (or ink-jet) printer capable of all the following: print, copy, scan, and fax.

MicroATX

A small, commonly used (as of this writing) form factor of case, motherboard, and power supply. Based on ATX.

MicroDIMM (Micro Dual Inline Memory Module)

Commonly used in subnotebook computers, each 144-pin MicroDIMM provides a 64-bit data path, so they are installed singly in 64-bit systems.

MIDI (Musical Instrument Digital Interface)

A standard or protocol used for the interface between a musical instrument or device and a computer system. It is used in digital synthesizers for playing and manipulating sound.

MMC (Microsoft Management Console)

Management application that draws upon a graphical user interface and a programming framework to allow the creation and saving of consoles. This is particularly important, since consoles are used to manage Windows-based software and hardware.

MMX (Multimedia Extensions)

A multimedia technology developed by Intel to improve the performance of its Pentium microprocessor. MMX technology included 57 new processor instructions and is said to improve multimedia application performance up to 60%.

Modem (Modulator-Demodulator)

A communication device used to convert signals so they can be transmitted over conventional telephone lines. A modem converts incoming analog signals to digital format and outgoing digital signals to analog format. It allows the computer to access a telephone line for the purpose of faxing, Internet access, data transfer between computers, or other tele-communications-related uses. Internal modems plug into expansion slots, while an external modem connects to a port on the computer.

monitor

A device resembling a television that displays the computer’s video images. Synonyms: screen, display.

motherboard

The large printed-circuit board to which all other parts are connected. Synonyms: system board, main board, desktop board.

MPEG (Motion Picture Experts Group)

A standards group that works with the ISO to establish rules and standards for audio and video compression. MPEG technology is used to make high-quality compressed files.

MSCDEX (Microsoft CD-ROM Extensions)

A software driver used in Windows 3x and DOS to allow the operating systems to communicate with CD-ROM devices. The actual file that contains the driver is called MSCDEX.EXE. More-efficient 32-bit CD-ROM drivers, such as CDFS, have replaced MSCDEX.EXE.

MSDS (Material Safety Data Sheet)

Designed to provide employers, employees, and EMS personnel with the proper procedures for various substances and chemicals, the data sheet is broken down into 10 sections: General Information; Ingredients; Physical Data; Fire and Explosion Data; Health Hazard Data; Reactivity Data; Spill, Leak, and Special Disposal Features; Special Protection Information; Special Precautions; and Transportation Data. Access to MSDSs include workplace laboratories, universities, the product’s distributor, and online.

multimedia

The combination of sound and various forms of graphics including video and animation. Although the prefix “multi” indicates more than one, many people incorrectly use the term to refer to sound only.

multiple-boot

A computer with three or more OSs that can be selected when booting.

multitester

A device used to test various properties of electrical currents and circuits such as voltage, continuity, and resistance. Most commonly used in computer repair for testing power supplies.