Computer Hardware Basics

Input Device

An input device is any peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system (such as a computer).

Input Device

Output Device

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world.

Output Device

Communication Device

Communication Device

System Unit

A system unit, also known as a base unit, is the main body of a desktop computer, typically consisting of an enclosure containing the motherboard, power supply, cooling fans, internal disk drives, and the memory modules and expansion cards that are plugged into the motherboard, such as video and network cards.

System Unit

MotherBoard

The main circuit board of a microcomputer. The motherboard contains the connectors for attaching additional boards. Typically, the motherboard contains the CPU, BIOS, memory, mass storage interfaces, USB ports, expansion slots, and all the controllers required to control standard peripheral devices, such as the display screen, keyboard, and disk drive. Collectively, all these chips that reside on the motherboard are known as the motherboard's chipset.

MotherBoard

System Clock

The system clock determines the clock speed of the computer which is the speed at which a microprocessor executes instructions. Every computer contains an internal clock that regulates the rate at which instructions are executed and synchronizes all the various computer components.

System Clock

Primary StorageRom Ram

BIOS

Primary storage, presently known as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. All computers have primary storage.

ROM (read-only memory): Computers almost always contain a small amount of read-only memory that holds instructions for starting up the computer. Unlike RAM, ROM cannot be written to

RAM (random access memory), a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers. The BIOS is boot firmware,

designed to be the first code run by a PC when powered on. The initial function of the BIOS is to identify, test, and initialize system devices such as the video display card, hard disk, and other hardware.

Primary StorageRom Ram

BIOS

Secondary Storage

Secondary storage is not directly accessible by the CPU. The computer must transfer the desired data into primary storage before it can use it. Secondary storage does not lose the data when the device is powered down—it is non-volatile. It is typically also much less expensive and can hold than primary storage. Consequently, modern computer systems typically have an order of magnitude more secondary storage than primary storage and data is kept for a longer time there.

In modern computers, hard disks are usually used as secondary storage.

Some other examples of secondary storage technologies are: flash memory (e.g. USB sticks or keys), floppy disks, magnetic tape, paper tape, punch cards, standalone RAM disks, and Zip drives.

Secondary Storage

CPU

Abbreviation for central processing unit, and pronounced as separate letters. The CPU is the brains of the computer. Sometimes referred to simply as the central processor, but more commonly called processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.

CPU

Bus

A collection of wires through which data is transmitted from one part of a computer to another. You can think of a bus as a highway on which data travels within a computer. When used in reference to personal computers, the term bus usually refers to internal bus. This is a bus that connects all the internal computer components to the CPU and main memory. There's also an

expansion bus that enables expansion boards to access the CPU and memory. Examples include PCI and PCI express for expansion boards and SATA for hard drives.

Bus

External

ExternalA bus that connects a computer to peripheral devices. The most commonly used external bus is the Universal Serial Bus (USB) but there is also Thunderbolt, Firewire and eSATA (External SATA).

An expansion card (also expansion board, adapter card or accessory card) in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system. Examples include video cards, sound cards, network cards, TV tuner cards.

Expansion Cards

Desktop Vs Server

• Designating a machine or hardwareas "server hardware“ or "server-class hardware" implies that it is more powerful and more importantly more reliable than standard personal computer or components

Desktop Vs Server