PC Upgrade and Repair Bible Desktop Edition phần 10 ppsx

IRC Internet Relay Chat. An Internet service that allows multiple users to con- verse in real time on different subjects (each subject is called a channel). Similar to instant messaging, but non-proprietary. IRQ Interrupt request. The identifier of a signal that a device can send to the processor to indicate it needs service. ISA Industry Standard Architecture. The bus used in the original IBM PC. Now obsolete, replaced by PCI. ISP Internet service provider. A company that sells dial-up (or other) access to the Internet. ITU International Telecommunications Union. ITU-TSS International Telecommunications Union-Telecommunications Standardization Sector. Kbps Kilobits per second (multiples of 1,024 bits per second). keys Notches on a memory module or other connector that prevent it from being installed incorrectly or into an incompatible system. kilobit Approximately 1,000 bits: 1 bit × 2 10 (that is, 1,024 bits). kilobyte Approximately 1,000 bytes: 1 byte × 2 10 (that is, 1,024 bytes). LAN Local area network. A data communications network confined to a lim- ited geographic area, with moderate to high data rates (10 to 1,000 Mbps, for example). The area served may consist of a single building or a campus-type arrangement. A LAN is typically owned by its users, includes some type of switching technology, and does not use common carrier circuits (although it may have gateways or bridges to other public or private networks). latency Delay between two events, such as the time delay between when the first bit of a packet is received and the last bit is forwarded. LCD Liquid crystal display. Two thin transparent surfaces (usually glass), with grooves full of a liquid crystal substance that are then polarized and electri- cally charged to reorient the crystal and selectively allow light to pass through. leakage Undesirable conductive paths in components, subsystems, and sys- tems; also the current through such paths. LED Light-emitting diode. Line In A connector on audio equipment to which a device such as a CD player or tape cassette player may be attached. See also Line Out. Line Out A connector on audio equipment to which audio components such as stereo speakers can be attached. See also Line In. 434 Glossary link A physical connection between two nodes in a network. It can consist of a data communication circuit or a direct channel (cable) connection. LISTSERV An automated mailing list distribution system. LISTSERVs are organ- ized by topic of interest and maintained on an ad hoc basis. local loop The line from a telephone customer’s premises to the telephone company CO (central office). MAC Media Access Control. A method of controlling access to a transmission medium, for example, Ethernet. master/slave Used to refer to the relationship of devices (especially ATA disk drives) on a communications channel. Discouraged as offensive in Los Angeles. Mb Megabit. MB Megabyte. Mbps Megabits per second (one million bits per second), a measurement of data transmission rate. MBps Megabytes per second (one million bytes per second). megabit Approximately one million bits: 1 bit × 1,024 2 (that is, 1,048,576 bits). megabyte Approximately one million bytes: 1 byte × 1,024 2 (that is, 1,048,576 bytes). memory A computer system’s high speed, random access storage. Memory stores data electronically in integrated circuits. memory bank A unit of memory in a computer, the size of which is determined by the computer’s CPU. memory cycle The minimum amount of time required for a memory to com- plete a cycle such as read, write, read/write, or read/modify/write. memory types See DRAM, EPROM, PROM, RAM, ROM, and SRAM. microATX A form factor specifying the size and layout of desktop computers. The specification extends to the definition of the power supply and its inter- face to the PC. micron A unit of measure equivalent to one-millionth of a meter; synonymous with micrometer. MIDI Musical Instrument Digital Interface. A standard that allows for the exchange of data between two music synthesizers or a synthesizer and a computer. Glossary 435 MIME Multipurpose Internet Mail Extensions. An Internet standard for con- verting multiple file formats to ASCII text prior to transmission in e-mail. MIPS Million instructions per second. A measurement of processor speed. MMC Multimedia Card. One of several flash memory form factors used for storage in cameras and other portable electronic devices. modulation A process by which signal characteristics are transformed to rep- resent information. motherboard Also known as logic board, main board, or system board; your computer’s main electronics board, which in most cases either contains all CPU, memory, and I/O functions or has expansion slots that support them. MPEG Moving Picture Experts Group. MPEG-1, -2, and -4 are types of lossy data compression for storage and playback of combined video and audio data. MPEG-3 (MP3) is a standard for lossy audio compression. MTBF Mean time between failures. MTTF Mean time to failure. MTTR Mean time to repair. MTU Maximum transmission unit. The largest possible unit of data that can be sent on a given network medium. Multilink PPP A variant of PPP for channel aggregation, used by connections over multiple 56 Kbps dial-up lines. Outlined in IETF RFC 1717. multimedia A combination of media used for entertainment, education, and communication. multitasking The execution of commands in such a way that more than one command is in progress at the same time. See also hyperthreading. nano Literally, one-billionth (10 –9 ). nanometer A measurement equal to one-billionth of a meter. The shorter- wavelength thinner-beam red laser incorporated in DVD players measures 650 nanometers, compared to 780 nanometers for a conventional CD player laser. nanosecond (ns) One-billionth of a second. Memory data access times are measured in nanoseconds. For example, memory access times for typical 30- and 72-pin SIMM modules range from 60 to 100 nanoseconds. Light travels approximately 8 inches in 1 nanosecond. NetBIOS Network Basic Input/Output System. Standard interface to networks on IBM PC and compatible systems. 436 Glossary network layer The protocol layer responsible for routing, switching, and sub- network access. network topology The arrangement of nodes usually forming a star, ring, tree, or bus pattern. NFS Network File System. nibble Usually 4 bits or half a byte. NIC Network interface card. NNTP Network News Transfer Protocol. The Internet protocol supporting Usenet newsgroups. node Any device connected to a network, including servers and workstations. nonvolatile memory Memory that retains information if power is removed and then reapplied. ns See nanosecond. NTFS NT file system. This alternative to the DOS FAT file system is used by Windows NT, 2000, and XP to provide increased performance and enhanced security. NTSC National Television Standards Committee. They devised the NTSC televi- sion broadcast system in 1953. Supports vertical resolution of 525 horizontal lines stacked on top of each other. There are 59.94 fields displayed per second. A field is a set of even lines, or odd lines. The odd and even fields are displayed sequentially, interlacing to form the full frame. One full frame is displayed every 1 ⁄30 of a second. open source Computer software for which the source code is made available for public examination and modification. See www.opensource.org. operating system Software controlling the overall operation of a multipurpose computer system, including memory allocation, input and output, interrupt processing, and scheduling. OSI Open Systems Interconnection. See OSI Reference Model. OSI Reference Model A seven-layer network architecture model of data com- munication protocols developed by ISO and CCITT. Each layer specifies partic- ular network functions such as addressing, flow control, error control, encapsulation, and reliable message transfer. packet A collection of bits comprising data and control information formatted for transmission from one node to another. packet filtering Examination of en-route packets by a router to decide whether or not to allow transmission of each packet. Glossary 437 packet switching A type of data transfer that occupies a communication link only during the time of actual data transmission. Messages are split into pack- ets and reassembled at the receiving end of the communication link. packetization Information that, instead of being transported as a constant stream of information, is transported as blocks. packet-switched network A network in which data is transmitted in units called packets. The packets can be routed individually over the best available network connection and reassembled to form a complete message at the destination. page One unit of information from a Web server. Also, the bits that can be accessed from one memory row address. page mode A now-obsolete memory mode in which if RAS is kept low and the DRAM is given a column address without being given a new row address, the chip will remember which row it was on the last time and automatically stay on that row. PAL Page Alternation Line. A European standard for television signals having 625 horizontal lines of vertical resolution. Fifty interlaced fields are displayed per second, or 25 frames per second. palette In 256-color modes, the palette defines the range of colors you can display simultaneously. Also, the hardware in a video board that stores the available colors. parity A method of data-integrity checking that adds a single bit to each unit (typically a byte) of data. In odd parity mode, the parity bit is set if the checked data contains an odd number of ones; in even parity mode, the parity bit is set if the checked data contains an even number of ones. parity bit A bit added to a group of bits to detect the presence of an error. patch cable An Ethernet cable with male RJ-45 connectors on either end. PCI Peripheral Component Interconnect. A type of high-speed computer bus. PCI Express A high-speed computer bus intended to replace PCI. PCI Express typically uses fewer data lines and can operate at higher speeds and over longer distances than PCI. PCMCIA Personal Computer Memory Card International Association. Now called PC Card. A standard for small, flat credit-card-sized devices used in notebook computers. peer-to-peer communications A type of communications and data exchange between peer entities (for example, two user PCs) on two or more networks. Contrast with client/server. peripheral A device installed on a computer system. 438 Glossary p-frame MPEG-2 frames constructed by analyzing previous frames and esti- mating where objects will be in the next frame. ping A program used to test reachability of destinations by sending them an ICMP echo request and waiting for a reply. Ping is also used as a verb: “Ping the site to see if it is available.” PIO Programmed Input/Output. A method of data transfer in which the host microprocessor transfers data to and from memory via the computer’s I/O ports. PIO is not as fast as direct memory access (DMA) and imposes a signifi- cant load on the processor. pits and lands Marks on the surface of a CD-ROM or DVD disc that are read by a laser as the series of ones and zeros. pixel A single dot on a display. Derived from the words picture and element. pixel shader A programmable graphics operation implemented on the video card to create custom lighting, coloring, and other effects on a per-pixel basis. Plug and Play A standard intended to overcome the configuration problems inherent in the ISA bus by letting adapters self-configure and automatically resolve system resources such as interrupts (IRQ), DMA, port addresses, and BIOS addresses. Largely obsolete per se with the advent of the PCI bus, but co- opted to refer to any device that automatically configures itself (for example, PCI, USB). polling A method of controlling the sequence of transmission by devices on a multipoint line by requiring each device to wait until the controlling processor requests it to transmit. POP Post Office Protocol. An Internet standard protocol for reading mail from a server. The commonly used version is POP3. port I/O address The number of the I/O port through which the processor communicates with a peripheral. POST Power-On Self-Test, a set of diagnostic routines that run when a com- puter is first turned on. POTS Plain Old Telephone Service. Really. POTS refers to the existing analog telephone lines, and is the universal term in the telecommunications industry. power down To turn the system’s power off. power up To turn the system’s power on. PPP Point-to-Point Protocol. Provides Internet protocol connections over serial circuits. PROM Programmable read-only memory. A version of a ROM that is program- mable once using special devices. Glossary 439 protocol A standardized set of rules that specify the format, timing, sequenc- ing, and/or error checking for data transmissions. PTT Public Telephone and Telegraph. A generic term for European telephone companies. Most are (currently) state owned and operated. The Deutsche Bundespost is one example of a PTT. pulse dialing Dialing a telephone line as if using the older-style rotary dial wheel. QoS Quality of service. Describes the delay, throughput, bandwidth, and other performance characteristics of a network connection. RAM Random access memory. A configuration of memory cells that holds data for processing by a computer’s CPU. The term random access means the CPU can retrieve data from any individual location at any time. Rambus Rambus DRAM is a memory standard capable of transferring 1.6 GB per second. RAS Row address strobe. The signal that tells the DRAM to accept the given address as a row address. Used with CAS and a column address to select a bit within the DRAM. refresh An electrical process used to maintain data stored in DRAM. The process of refreshing electrical cells on a DRAM component is similar to that of recharging batteries. Different DRAM components call for different refresh methods; and some (such as SDRAM) perform refresh automatically. refresh rate Also called vertical scan rate, the speed at which the screen is repainted. Typically, color displays must be refreshed at 60 times per second to avoid flicker. Also, a specification determined by the number of rows on a DRAM component that must be refreshed. register-level compatibility Complete compatibility at the hardware level from the software point of view. remote user A user who needs client access to a server over WAN links. removability A feature where the media in a removable media disk drive, or the entire drive, can be removed and then replaced while the computer remains in operation, without causing problems to the hardware or operating system. repeater Used to extend the network topology, allowing a cable’s segments to be lengthened beyond normal specification limits. See also hub. RGB Red/green/blue, a color model typically used with monitors. RISC Reduced instruction set computing. RISC chips, such as in the PowerPC processor used in Apple computers, implement simpler instructions than CISC chips, such as the x86 processors used in Windows machines. 440 Glossary RMA Return Material Authorization. Required if a customer desires to return products to the manufacturer or supplier. ROM Read-only memory. Generally a chip on a computer or I/O card with soft- ware programmed inside of it that controls some function. router A protocol-dependent device that connects subnetworks together. It is useful in breaking down a very large network into smaller subnetworks. routing protocol A protocol that accomplishes routing through the implemen- tation of a specific routing algorithm. routing table A table stored in a router or some other internetworking device that keeps track of routes (and, in some cases, metrics associated with those routes) to particular network destinations. routing update A message sent from a router to indicate network reachability and associated cost information. Routing updates are typically sent at regular intervals and after a change in network topology. row Part of the RAM array; a bit can be stored where a column and a row intersect. RS-232 A serial data transmission interface specification. RTFM Read the Manual. Acronym suggesting a response to an easily answered question. Sometimes found on automotive license plates. sample A measurement of sound taken during a certain duration. In digital recording, sampling means recording voltages that make a sound as a sequence of numerical values representing the sound’s amplitude. scan rate The frequency in hertz (Hz) at which the monitor is scanned hori- zontally. Generally, the higher the scan rate, the higher the resolution. SCSI Small Computer System Interface. A bus interface standard that defines standard physical and electrical connections for devices. SCSI provides a standard interface that enables many different kinds of devices, such as disk drives, magneto-optical disks, CD-ROM drives, and tape drives to interface with the host computer. SD Secure digital. One of several flash memory form factors used for storage in cameras and other portable electronic devices. SDRAM Synchronous dynamic random access memory. Delivers bursts of data at very high speeds using a synchronous interface. sector The smallest storage access unit on a hard drive. seek time The average time it takes for a hard drive to position its heads to a specific sector. Glossary 441 self-refresh A memory technology that enables SDRAM and some other mem- ory technologies to refresh on its own, independent of the CPU or external refresh circuitry. semiconductor An element, such as silicon, that has intermediate electrical conductivity between conductors and insulators, and in which conduction takes place by means of holes and electrons. Serial ATA A higher speed modification of the parallel ATA disk drive interface to use fewer, faster wires between drive and PC. serial interface An interface that requires serial transmission, or the transfer of information in which the bits composing a character are sent sequentially. Implies only a single transmission channel. serial port A connection for a serial device like a mouse or a modem. serial presence detect Indicator memory and pins on SIMMs and DIMMs that provide size and timing information to the PC. server A computer that provides shared resources, such as files, printers, and servers, to the network. SIMM Single in-line memory module. A printed circuit board with contacts and memory devices that plugs into a computer’s memory socket. SMTP Simple Mail Transfer Protocol. A protocol governing mail transmissions defined in RFC 821. The associated message format descriptions are in RFC 822. SNMP Simple Network Management Protocol. A network management system for TCP/IP-based internets. One of the most egregious uses ever of the word simple. SODIMM Small outline dual inline memory module. A smaller and thinner ver- sion of a standard DIMM. The small outline DIMM is about half the length of a typical 72-pin SIMM. SODIMMs are typically used in laptop computers. soft error In memory components, a correctable data error made by a device not having anything physically wrong with it. sound file Any file that holds sound data, including MIDI (.mid), wave (.wav), and MPEG-3 (.mp3). SPD See serial presence detect. spoofing The use of a forged network source address to circumvent a firewall or mask the sender. SRAM Static random access memory. An integrated circuit similar to a DRAM (dynamic random access memory) with the exception that the memory does not need to be refreshed. 442 Glossary star topology A network topology in which nodes are connected to a common device such as a hub or concentrator. storage A medium designed to hold data, such as a hard disk or CD-ROM. storage capacity The limit to the amount of information that can be recorded on any recording medium. In DVD, this varies from 4.7GB on a DVD-5 disc to 17GB on a DVD-18 disc. STP Shielded twisted-pair. A common transmission medium that consists of Receive (RX) and Transmit (TX) wires twisted together to reduce crosstalk. The twisted-pair is shielded by a braided outer sheath. surround sound A multiple-channel sound system that produces an audio ambience similar to the cinema sound experience. S-video An interface between video source and display providing higher-quality signal transmission than the more common RCA video connector because it separates the chrominance and luminance signal components. switched Ethernet An Ethernet hub with integrated MAC layer bridging or switching capability to provide each port with full LAN bandwidth; separate transmissions can occur on each port of the switching hub, and the switch fil- ters traffic according to the destination MAC address. synchronous DRAM A DRAM technology that uses a clock to synchronize signal input and output on a memory chip. The clock is coordinated with the CPU clock so the timing of the memory chips and the timing of the CPU are coordinated. system board See motherboard. T-connector A T-shaped device with two female and one male BNC connectors. TCP Transmission Control Protocol. See also TCP/IP and IP. TCP/IP Transmission Control Protocol/Internet Protocol. A set of protocols developed by the U.S. Defense Department’s Advanced Research Projects Agency (ARPA) during the early 1970s. Its intent was to develop ways to con- nect different kinds of networks and computers. Telnet The Internet standard protocol to connect to a computer as a remote terminal. timbre How the ear identifies and classifies sound. Example: The timbre of the same note played by two different instruments (flute and tuba) will not be the same. topology The physical layout of a network. The principal LAN topologies are bus, ring, and star. Glossary 443 [...]... of, 436 modem and, 159 network and, 175 monitor See also display brightness, contrast, and, 99, 104 choosing, 106 color settings, 81–83 controls, 102 104 CRT (cathode ray tube) color balance, tracking, purity, and saturation, 99 101 dot pitch, 106 focus and convergence, 97–99 geometric distortion, 102 ghosting, 101 102 replacement of, 93 DDC-compatible, 105 106 editing digital video and, 285–286 flat... number and accuracy of colors, 321 resolution, 321–323 software, 324–325 screen brightness, contrast, and, 99, 104 choosing, 106 color settings, 81–83 controls, 102 104 CRT (cathode ray tube) color balance, tracking, purity, and saturation, 99 101 dot pitch, 106 focus and convergence, 97–99 geometric distortion, 102 ghosting, 101 102 replacement of, 93 DDC-compatible, 105 106 editing digital video and, ... viewing and rendering pipeline, 85–86 10Base-T, 100 Base-T, and 100 0Base-T, 421 10Base-2, 179–180, 389, 421 103 error code, 382 16550 chip, 162, 309– 310 802, 421 A AC-3, 421 Accelerated Graphics Port (AGP) connector, 73, 74 description of, 422 slot, 52 video and, 83 accelerator 3D video, 83–86 video card and, 41 Acceptable Use Policy (AUP), 421 access time description of, 422 disk and, 38, 114 memory and, ... 94–97, 351 multimedia, 104 105 pixels and, 79–80 placing to minimize glare, 106 repairing, 378 technical characteristics of, 93 television compared to, 79 television in window of, 90–91 unresponsive, 384 video card and, 39 video data path, 81 Moore’s Law, 14 motherboard See also chipset AMD processor and, 60 ATA drive and, 125–126 built-in Ethernet adapter and, 184 bus and, 67 case and, 329–330 checking,... 425 case airflow and heat buildup, 333 ATX form factor, 337–339 choosing, 339–340 cooling, 333–337 for desktop PC, 332 dust in, 376, 377, 391 opening, 380 overview of, 329–331 parts of, 331–332 taking apart, 376–378 cathode ray tube (CRT) monitor color balance, tracking, purity, and saturation, 99 101 dot pitch, 106 focus and convergence, 97–99 geometric distortion, 102 ghosting, 101 102 replacement... attacks and, 242 external hard drive and, 151–153 removable disk and, 145 removable storage and, 150–151 video clips, 286 backlight of LCD panel, 94 backplane, 67 backup, 423 bandwidth description of, 423 maximum video, 101 memory and, 36 surveillance system and, 360, 361 bank, 424 base station, 185, 189 baseband transmission, 175, 177, 424 basic input-output system (BIOS) automatic detection and configuration... distortion, 102 parity, 438 parity bit, 438 partitioning disk, 385 patch cable, 438 patch cord, 182 PC Card, 75–76, 350 PC CardBus, 350 PC Toys: 14 Cool Projects for Home, Office, and Entertainment (Barry Press & Marcia Press), 359 PCI Express, 70 PCI (Peripheral Component Interconnect) bus chipset and, 71–72 description of, 69–70 ISA bus compared to, 68 bus slot, 52 connector, 73, 74 description of, 438 PCL... multimedia, 104 105 pixels and, 79–80 placing to minimize glare, 106 repairing, 378 technical characteristics of, 93 television compared to, 79 television in window of, 90–91 unresponsive, 384 video card and, 39 video data path, 81 screwdriver, 10 screws, 380, 399 SCSI (Small Computer System Interface), 441 SD (secure digital), 441 Index ✦ S SDRAM (synchronous dynamic random access memory) chipset and, 72... 176, 177, 431 LAN and, 194–195 waveform audio and, 258 functioning machine, problems in, 387–388 fuse, 383 Index ✦ G—H 457 G H game controller, 296–300 game pad, 299 games display update performance and, 41 Internet service and, 171 matching video hardware and software, 91 modem and, 172–173 multi-player, 203 Quake, 232 sound system for, 271 3D video accelerator and, 83–86 USB mouse and, 306 gateway,... crystal, 312–313 pincushion control, 103 pincushion distortion, 102 ping utility, 225–226, 439 Pinnacle Systems PCTV Deluxe, 284, 285 Studio 8, 284, 285, 286, 287–288 Studio Deluxe PCI video capture card, 283, 284 pins in connector, 343 PIO (Programmed Input/Output), 439 pipelining, 53–54, 55 pits and lands, 439 pixel description of, 439 LCD panel and, 79–80 video card and, 39 pixel shader, 439 Plain Old . accelerator, 83–86 3D viewing and rendering pipeline, 85–86 10Base-T, 100 Base-T, and 100 0Base-T, 421 10Base-2, 179–180, 389, 421 103 error code, 382 16550 chip, 162, 309– 310 802, 421 A AC-3, 421 Accelerated. purity, and saturation, 99 101 dot pitch, 106 focus and convergence, 97–99 geometric distortion, 102 ghosting, 101 102 replacement of, 93 CCITT (Consultative Committee for International Telegraph and Telephone),. tube) monitor color balance, tracking, purity, and saturation, 99 101 dot pitch, 106 focus and convergence, 97–99 geometric distortion, 102 ghosting, 101 102 replacement of, 93 Crucial Web site, 397,