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a. Perkakasan yang menukar isyarat digital kepada isyarat
analog dan sebaliknya.
b. Terdapat dua jenis modem iaitu modem luaran dan modem
dalaman.
c. Modem luaran adalah alat berasingan daripada komputer.
d. Modem dalaman adalah expansion card yang
boleh dimasukkan kepada expansion slot pada papan ibu
komputer.
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a. Kad rangkaian dipasang ke dalam setiap komputer.
b. Ketika penghantaran maklumat di antara dua buah komputer
dilakukan, maklumat yang akan dihantar akan melalui proses
pengendalian. Kad rangkaian bertanggungjawab melakukan proses ini.
c. Kad antaramuka rangkaian mempunyai 3 kelajuan duplex penuh
iaitu 10MB, 100MB dan 10/100MB.
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a. Berperanan untuk menghubungkan setiap komputer di dalam
LAN.
b. Hub selalunya mengandungi 8, 12, 32 port untuk
menyambungkan komputer-komputer atau alat-alat lain di dalam rangkaian.
c. Hub mempunyai 3 kelajuan duplex penuh iaitu 10MB, 100MB
dan 10/100MB.
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a. Talian sambungan di antara setiap peranti di dalam
rangkaian merupakan kabel.
b. Dalam memainkan peranan sebagai perantara dalam
penghantaran maklumat.
c. Spesifikasi kabel yang berbeza mempunyai kelajuan
penghantaran yang berlainan.
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a. Adalah sebuah alat yang menerima isyarat daripada media
penghantaran, menguatkan semula isyarat tersebut dan menghantar semula
isyarat berkenaan ke destinasinya.
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a. Adalah sebuah alat yang menyambungkan 2 LAN yang
menggunakan protokol yang sama seperti Ethernet.
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a. Adalah alat yang menyambungkan beberapa rangkaian termasuk
rangkaian yang menggunakan protokol yang berbeza.
b. Ia adalah alat komunikasi pintar yang boleh membuat
penghantaran data menggunakan laluan yang paling pantas.
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a. Adalah kombinasi perkakasan dan perisian.
b. Kegunaanya adalah untuk menyamungkan rangkaian yang
menggunakan protokol yang berbeza.
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Tuesday, 24 April 2012
perkakasan rangkaian
Sunday, 22 April 2012
topology
Network topology
From Wikipedia, the free
encyclopedia
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This article needs additional citations forverification.
Please helpimprove this article by adding citations to reliable sources. Unsourced material may be challengedand removed. (December
2011)
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This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations.
Please improvethis
article by introducing more precise citations.(November 2011)
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Diagram of different
network topologies.
Network topology is the layout pattern of
interconnections of the various elements (links, nodes, etc.) of a computer[1][2] or biological
network.[3]Network
topologies may be physical or logical. Physical topology refers to the physical
design of a network including the devices, location and cable installation. Logical topology refers to how data is
actually transferred in a network as opposed to its physical design. In general
physical topology relates to a core network whereas logical topology relates to
basic network.
Topology can be understood as the shape or
structure of a network. This shape does not necessarily correspond to the
actual physical design of the devices on the computer network. The computers on
a home network can be arranged in a circle but it does not necessarily mean
that it represents a ring topology.
Any particular network topology is determined
only by the graphical mapping of the configuration of physical and/or logical
connections between nodes. The study of network topology uses graph theory.
Distances between nodes, physical interconnections, transmission rates, and/or
signal types may differ in two networks and yet their topologies may be
identical.
Tuesday, 17 April 2012
ip address
IP address
From Wikipedia, the free encyclopedia
For the Wikipedia user access level, seeWikipedia:User access levels#Unregistered_users.
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer networkthat uses the Internet Protocol for communication.[1]An IP address serves two principal functions: host or network interface identification and locationaddressing. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."[2]
The designers of the Internet Protocol defined an IP address as a 32-bit number[1] and this system, known as Internet Protocol Version 4 (IPv4), is still in use today. However, due to the enormous growth of theInternet and the predicted depletion of available addresses, a new addressing system (IPv6), using 128 bits for the address, was developed in 1995,[3]standardized as RFC 2460 in 1998,[4] and itsdeployment has been ongoing since the mid-2000s.
IP addresses are binary numbers, but they are usually stored in text files and displayed in human-readablenotations, such as 172.16.254.1 (for IPv4), and 2001:db8:0:1234:0:567:8:1 (for IPv6).
The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally and delegates five regional Internet registries (RIRs) to allocate IP address blocks to local Internet registries(Internet service providers) and other entities.
Sunday, 18 March 2012
storage
In a computer, storage is the place where data is held in an electromagnetic or optical form for access by a computer processor. There are two general usages.
1) Storage is frequently used to mean the devices and data connected to the computer through input/output operations - that is, hard disk and tape systems and other forms of storage that don't include computer memory and other in-computer storage. For the enterprise, the options for this kind of storage are of much greater variety and expense than that related to memory. This meaning is probably more common in the IT industry than meaning 2.
2) In a more formal usage, storage has been divided into: (1) primary storage, which holds data in memory (sometimes called random access memory or RAM
) and other "built-in" devices such as the processor's L1 cache, and (2) secondary storage, which holds data on hard disks, tapes, and other devices requiring input/output operations
1) Storage is frequently used to mean the devices and data connected to the computer through input/output operations - that is, hard disk and tape systems and other forms of storage that don't include computer memory and other in-computer storage. For the enterprise, the options for this kind of storage are of much greater variety and expense than that related to memory. This meaning is probably more common in the IT industry than meaning 2.
2) In a more formal usage, storage has been divided into: (1) primary storage, which holds data in memory (sometimes called random access memory or RAM
Learn More
mother board
Motherboard
From Wikipedia, the free encyclopedia
In personal computers, a motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple computers, the logic board.[1] It is also sometimes casually shortened to mobo.
Motherboard for an Acer desktop personal computer, showing the typical components and interfaces that are found on a motherboard. This model was made by Foxconn in 2008, and follows the ATX layout (known as the "form factor") usually employed for desktop computers. It is designed to work with AMD's Athlon 64 processor.
A motherboard of a Vaio E series laptop (right)
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers.
The most popular computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment
The term mainboard is applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems and controlling boards in televisions, washing machines, etc. A motherboard specifically refers to a printed circuit board with expansion capability.
A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables, although in modern computers it is increasingly common to integrate some of these peripherals into the motherboard itself.
An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.
Modern motherboards include, at a minimum:
Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.
Block diagram of a modern motherboard, which supports many on-board peripheral functions as well as several expansion slots.With the steadily declining costs and size of integrated circuits, it is now possible to include support for many peripherals on the motherboard. By combining many functions on one PCB, the physical size and total cost of the system may be reduced; highly integrated motherboards are thus especially popular in small form factor and budget computers.
For example, the ECS RS485M-M,[5] a typical modern budget motherboard for computers based on AMD processors, has on-board support for a very large range of peripherals:
A standard ATX motherboard will typically have one PCI-E 16x connection for a graphics card, two conventional PCI slots for various expansion cards, and one PCI-E 1x (which will eventually supersede PCI). A standard EATX motherboard will have one PCI-E 16x connection for a graphics card, and a varying number of PCI and PCI-E 1x slots. It can sometimes also have a PCI-E 4x slot. (This varies between brands and models.)
Some motherboards have two PCI-E 16x slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia) and Crossfire (for ATI). These allow 2 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming and video editing.
As of 2007, virtually all motherboards come with at least four USB ports on the rear, with at least 2 connections on the board internally for wiring additional front ports that may be built into the computer's case. Ethernet is also included. This is a standard networking cable for connecting the computer to a network or a modem. A sound chip is always included on the motherboard, to allow sound output without the need for any extra components. This allows computers to be far more multimedia-based than before. Some motherboards contain video outputs on the back panel for integrated graphics solutions (either embedded in the motherboard, or combined with the microprocessor, such as the Intel HD Graphics). A separate card may still be used.
Some small form factor computers and home theater PCs designed for quiet and energy-efficient operation boast fan-less designs. This typically requires the use of a low-power CPU, as well as careful layout of the motherboard and other components to allow for heat sink placement.
A 2003 study[6] found that some spurious computer crashes and general reliability issues, ranging from screen image distortions to I/O read/write errors, can be attributed not to software or peripheral hardware but to aging capacitors on PC motherboards. Ultimately this was shown to be the result of a faulty electrolyte formulation.[7]
A microATX motherboard with some faulty capacitors.
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[edit] History
Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connected by a backplane consisting of a set of slots themselves connected with wires; in very old designs the wires were discrete connections between card connector pins, but printed circuit boards soon became the standard practice. The Central Processing Unit, memory and peripherals were housed on individual printed circuit boards which plugged into the backplate. During the late 1980s and 1990s, it became economical to move an increasing number of peripheral functions onto the motherboard (see below). In the late 1980s, motherboards began to include single ICs (called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. As of the late 1990s, many personal computer motherboards supported a full range of audio, video, storage, and networking functions without the need for any expansion cards at all; higher-end systems for 3D gaming and computer graphics typically retained only the graphics card as a separate component.The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers.
The most popular computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment
The term mainboard is applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems and controlling boards in televisions, washing machines, etc. A motherboard specifically refers to a printed circuit board with expansion capability.
[edit] Overview
A motherboard, like a backplane, provides the electrical connections by which the other components of the system communicate, but unlike a backplane, it also connects the central processing unit and hosts other subsystems and devices.A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables, although in modern computers it is increasingly common to integrate some of these peripherals into the motherboard itself.
An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.
Modern motherboards include, at a minimum:
- sockets (or slots) in which one or more microprocessors may be installed[2]
- slots into which the system's main memory is to be installed (typically in the form of DIMM modules containing DRAM chips)
- a chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses
- non-volatile memory chips (usually Flash ROM in modern motherboards) containing the system's firmware or BIOS
- a clock generator which produces the system clock signal to synchronize the various components
- slots for expansion cards (these interface to the system via the buses supported by the chipset)
- power connectors, which receive electrical power from the computer power supply and distribute it to the CPU, chipset, main memory, and expansion cards.[3]
Additionally, nearly all motherboards include logic and connectors to support commonly used input devices, such as PS/2 connectors for a mouse and keyboard. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard. Occasionally video interface hardware was also integrated into the motherboard; for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards.
Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.
[edit] CPU sockets
Main article: CPU socket
A CPU socket or slot is an electrical component that attaches to a printed circuit board (PCB) and is designed to house a CPU (also called a microprocessor). It is a special type of integrated circuit socket designed for very high pin counts. A CPU socket provides many functions, including a physical structure to support the CPU, support for a heat sink, facilitating replacement (as well as reducing cost), and most importantly, forming an electrical interface both with the CPU and the PCB. CPU sockets can most often be found in most desktop and server computers (laptops typically use surface mount CPUs), particularly those based on the Intel x86 architecture on the motherboard. A CPU socket type and motherboard chipset must support the CPU series and speed.[edit] Integrated peripherals
For example, the ECS RS485M-M,[5] a typical modern budget motherboard for computers based on AMD processors, has on-board support for a very large range of peripherals:
- disk controllers for a floppy disk drive, up to 2 PATA drives, and up to 6 SATA drives (including RAID 0/1 support)
- integrated graphics controller supporting 2D and 3D graphics, with VGA and TV output
- integrated sound card supporting 8-channel (7.1) audio and S/PDIF output
- Fast Ethernet network controller for 10/100 Mbit networking
- USB 2.0 controller supporting up to 12 USB ports
- IrDA controller for infrared data communication (e.g. with an IrDA-enabled cellular phone or printer)
- temperature, voltage, and fan-speed sensors that allow software to monitor the health of computer components
[edit] Peripheral card slots
A typical motherboard of 2009 will have a different number of connections depending on its standard.A standard ATX motherboard will typically have one PCI-E 16x connection for a graphics card, two conventional PCI slots for various expansion cards, and one PCI-E 1x (which will eventually supersede PCI). A standard EATX motherboard will have one PCI-E 16x connection for a graphics card, and a varying number of PCI and PCI-E 1x slots. It can sometimes also have a PCI-E 4x slot. (This varies between brands and models.)
Some motherboards have two PCI-E 16x slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia) and Crossfire (for ATI). These allow 2 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming and video editing.
As of 2007, virtually all motherboards come with at least four USB ports on the rear, with at least 2 connections on the board internally for wiring additional front ports that may be built into the computer's case. Ethernet is also included. This is a standard networking cable for connecting the computer to a network or a modem. A sound chip is always included on the motherboard, to allow sound output without the need for any extra components. This allows computers to be far more multimedia-based than before. Some motherboards contain video outputs on the back panel for integrated graphics solutions (either embedded in the motherboard, or combined with the microprocessor, such as the Intel HD Graphics). A separate card may still be used.
[edit] Temperature and reliability
Main article: Computer cooling
Motherboards are generally air cooled with heat sinks often mounted on larger chips, such as the Northbridge, in modern motherboards. Insufficient or improper cooling can cause damage to the internal components of the computer and cause it to crash. Passive cooling, or a single fan mounted on the power supply, was sufficient for many desktop computer CPUs until the late 1990s; since then, most have required CPU fans mounted on their heat sinks, due to rising clock speeds and power consumption. Most motherboards have connectors for additional case fans as well. Newer motherboards have integrated temperature sensors to detect motherboard and CPU temperatures, and controllable fan connectors which the BIOS or operating system can use to regulate fan speed. Some computers (which typically have high-performance microprocessors, large amounts of RAM, and high-performance video cards) use a water-cooling system instead of many fans.Some small form factor computers and home theater PCs designed for quiet and energy-efficient operation boast fan-less designs. This typically requires the use of a low-power CPU, as well as careful layout of the motherboard and other components to allow for heat sink placement.
A 2003 study[6] found that some spurious computer crashes and general reliability issues, ranging from screen image distortions to I/O read/write errors, can be attributed not to software or peripheral hardware but to aging capacitors on PC motherboards. Ultimately this was shown to be the result of a faulty electrolyte formulation.[7]
- For more information on premature capacitor failure on PC motherboards, see capacitor plague.
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