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- L1 cache
- Level 1 cache is cache built into the microprocessor and contains a subset of the contents of the L2 cache.
- L2 cache
- Level 2 cache is cache that is external to the microprocessor. L2 cache contains a subset of the contents of main memory. The design of the memory and L2 cache is a significant way designers differentiate their systems. High-end Pentium systems may use 256-512KB of pipelined,synchronous-burst L2 cache memory together with EDO DRAM. Mainstream systems may use less expensive memory alternatives, such as asynchronous static RAM(SRAM) with fast-page mode DRAM.
- LAN
- See Local-area network.
- LAN Manager
- A networking operating system, developed by Microsoft and 3Com, that runs on 80386,80486(and better) computers. The file-server software is a version of OS/2; client PCs can be OS/2,DOS,Unix, or Macintosh-based. Disk mirroring, disk duplexing, and UPS-monitoring functions are all available, and the operating system supports IPX/SPX, TCP/IP and NetBEUI communications protocols.
- LAN Server
- IBM's version of LAN Manager
- LAN cache
- The disk caching program that comes with LANtastic
- LANtastic
- A peer-to-peer network operating system that was once the most popular choice for small networks, before the built-in Windows for Workgroups and Windows 95 came along.
- laptop computer
- A small portable computer light enough to carry comfortably, with a flat screen and keyboard that fold together.
Laptops are battery-operated, often have a thin,backlit or sidelit LCD display screen, and some models can even mate with a docking station to perform as a full-sized desktop system back at the office. Advances in battery technology allow laptop computers to run for many hours between charges, and some models have a set of business applications built into ROM.
- laser printer
- A high-resolution non-impact printer that uses a variation of the electrophotographic process used in photocopying machines to print text and graphics onto paper.
A laser printer uses a rotating disc to reflect laser beams onto a photosensitive drum, where the image of the page is converted into an electrostatic charge that attracts and holds the toner. A piece of charged paper is then rolled against the drum to transfer the image, and heat is applied to fuse the toner and paper together to create the final image.
- LASTDRIVE
- A line in CONFIG.SYS that tells DOS how many drive letters to set aside for itself. NetWare uses this setting to determine which drive letter to map to the server's login directory.
- LAT (Local Area Transport)
- DEC's protocol designed specifically for terminal servers.
- latency
- The time that elapses between issuing a request for data, and actually starting the data transfer.
In a hard disk, this translates into the time it takes to position the disk's read/write head and rotate the disk so that the required sector or cluster is under the head. Latency is just one of many factors that influence disk access speeds.
- layered driver
- One of a collection of drivers that responds to the same IRPs. Layered driver describes the highest-level and lowest-level drivers in a chain of layered drivers that process the same IRPs, along with all intermediate drivers in the chain.
- layout
- In printed-circuit board design, the arrangement of the individual components on the circuit board.
- LBA
- Logical block addressing. A method used with SCSI and IDE disk drives to translate the cylinder, head, and sector specifications of the drive into addresses that can be used by an enhanced BIOS. LBA is used with drives that are larger than 528MB.
- LCD monitor
- A monitor that uses liquid-crystal display technology. Many laptop and notebook computers use LCD displays because of their low power requirements.
- LDAP (Lightweight Directory Access Protocols)
- A protocol used to look up information such as user names and e-mail addresses in an X.500-compatible directory service.
- legacy
- Any feature in the PC system based on older technology for which compatibility continues to be maintained in other system components.
- letter quality
- A printer mode that produces text higher in quality than draft mode. As the name suggests, letter quality printing is supposed to be good enough to be used in business letters, and therefore comparable to typewriter output. Laser printers, some ink-jet printers and all daisy-wheel printers produce letter-quality output; certain high-end dot-matrix printers can produce letter-quality output, but most do not.
- Light-emitting Diode (LED)
- A small semiconductor device that emits light as current flows through it. LEDs are often used as activity lights on computer peripherals such as hard disk drives and modems.
- light pen
- A light-sensitive input device shaped like a pen, used to draw on the computer screen or to make menu selections. As the tip of the light pen makes contact with the screen, it sends a signal back to the computer containing the x-y coordinates of the pixels at that point.
- line adapter
- In communications, a device such as a modem that converts a digital signal into a form suitable for transmission over a communications channel.
- line printer
- Any printer that prints a complete line at a time, rather than printing one character at a time ( as a dot-matrix or daisy wheel printer does), or one page at a time(as a laser printer does). Line printers are very high-speed printers,and are common in the coroporate environment where they are used with mainframe computers,minicomputers, and networked systems.
- line sharing device
- A small electronic device that allows a fax machine and a telephone answering machine to share the same phone line. The device answers the call and listens for the characteristic high-pitched fax carrier signal. If this signal is detected, the call is routed to the fax machine; if it is not detected, the call is sent to a telephone or answering machine instead.
- Link-local addresses
- Special IPv6 addresses that begin with FE80: They are designed for use on a single network segment and are not forwarded by any router. They permit communication with only those neighboring systems directly connected to the same part of the network (link)
- Liquid Crystal Display (LCD)
- A display technology common in portable computers that uses electric current to align crystals in a special liquid.
The rod-shaped crystals are contained between two parallel transparent electrodes, and when current is applied, they change their orientation, creating a darker area. Many LCD screens are also back-lit or side-lit to increase visibility and reduce the possibility of eyestrain.
- LLC sublayer
- The logical link sublayer of layer 2 of the OSI reference model. The LLC is addressed by the IEEE 802.2 standard.
- Local Area Network(LAN)
- A group of computers and associated peripherals connected by a communications channel capable of sharing files and other resources between several users.
- local bus
- A PC bus specification that allows peripherals to exchange data at a rate faster than the 8 megabytes per second allowed by the ISA, and the 32 megabytes per second allowed by the EISA definitions. Local bus can acheive a maximum data rate of133 megabytes per second with a 33MHz bus speed, 148 megabytes per second with a 40MHz bus, or 267 megabytes per second with a 50 MHz bus. VESAs video cards have been the main peripheral to benefit from local bus use.
Also defined as, a fast expansion bus found on 486 and Pentium computers that operates at a higher speed than the old ISA bus and allows 32-bit data transfers. Two types are commonly found:VESA and PCI. Many 486 comps include several VESA local bus slots, but newer Pentium comps use PCI slots. For best network performance,all servers should have VESA or PCI disk I/O and network interface cards(NICs).
- local computer
- Is the PC you're sitting in front of basically as opposed to a host computer, which is the computer you're trying to get information from.
- local disk
- In networking, a disk attached to a workstation rather than to the file server.
- local printer
- In networking, a printer attached to a workstation rather than to the file server or a print server.
- local resources
- Disk drives, printers, and other devices that are attached directly to a workstation rather than accessed via the network.
- LocalTalk
- Apple's scheme for cabling Macintosh networks by using the Mac's printer ports. PhoneNET is a cabling scheme that's compatible with Local Talk but less expensive.
- logical drive
- The internal division of a large hard disk into smaller units. One single physical drive may be organized into several logical drives for convenience; DOS supports up to 23 logical drives on a system. On a single-floppy system, the disk drive can function as both logical drive A and logical drive B, depending on the exact circumstances.
- login
- The process of identifying oneself to the network(or a specific network server) and gaining access to network resources.
- LOGIN
- The NetWare command used to log in to a NetWare network.
- LOGIN directory
- In NetWare, a network directory that's mapped to the workstation before the user has logged in. The LOGIN directory contains commands and programs that are accessible to every computer on the network, whether or not a user has logged in. Chief among these commands is the LOGIN command.
- login name
- In a Windows network, the name that identifies a user uniquely to the network. Same as username or user ID.
- login script
- A file of NetWare commands that is executed when a user logs in.
- logon
- See login.
- logout
- The process of leaving the network. When you log out, any network drives or printers you were connected to become unavailable to you.
- LOGOUT
- In NetWare, the command you use to log out.
- long file name
- The ability of a file system to take advantage of multiple-character file names. Several OSes are not limited to the Dos"8.3" file-naming convention of 8 characters before a period and three more optional characters forming the filename extension. Unix,Win9x,WinNT,OS/2, and Mac file systems can all manage long file names, even those containing spaces, more than one period, and mixed upper- and lower-cased letters.
- long-haul
- A modem or other communications device that can transmit information over long distances.
- loopback address
- 0:0:0:0:0:0:0:1(or just : :) It is a special IPv6 address that allows the system to send a message to itself for testing. Other IPv6 special addresses are:unspecified address, site-local address,link-local address,multicast and anycast addresses.
- lossless compression
- Ensures that the original data is exactly recoverable with no loss in image quality.
- lossy compression
- The original data is not completely recoverable. Although image quality may suffer, many experts believe that up to 95 percent of the data in a typical image may be discarded without a noticeable loss in apparent resolution.
- lost chain
- A part of a file, consisting of one or more clusters, that no longer has an entry in the FAT, and so can't be reconnected to the rest of the file. The DOS command CHKDSK detects these lost chains, converting them into files so that you can delete them and recover the disk space they take up. You can also examine the contents of these lost chains after CHKDSK has recovered them, bu the chance of the contents being usable is very slim indeed.
- lost cluster
- A cluster,originally once part of a file, for which there is now no FAT entry. Use the DOS command CHKDSK to convert lost clusters into files. You can then examine the contents of the cluster, and decide if you want to keep it or delete it and recover the disk space that it occupies.
- low-level format
- The process that creates the tracks and sectors on a blank hard disk or floppy disk; sometimes called the physical format. Most hard disks are already low-level formatted; however, floppy disks receive both a low and a high-level format (or logical format) when you use the DOS or OS/2 command FORMAT.
- low resolution
- In monitors and printers, a description of low-quality output, lacking sharpness or definition. Resolution is determined by the technology used to create the output.
- LPTx ports
- In DOS, the device name used to denote a parallel communications port, often used with a printer. DOS supports three parallel ports:LPT1,LPT2,and LPT3, and OS/2 adds support for network ports LPT4 through LPT9.
LPT1:is usually the first printer port on a PC. If a computer has a local printer, it will more than likely be attached to this port. That's why its a good idea to set up printer redirections using LPT2 and LPT3.
- LRU
- Least-recently used. Algorithm for paging.
- LSAPI(Licencense Service Application Programming Interface)
- A system for centralized software license management. LSAPI provides a set of program calls that allows a developer to create centralized software licensing applications.
See WOSA.
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