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NAME: ODOGWU PAUL CHIDOZIE
DEPARTMENT: ELECTRICAL/ELECTRONICS
ENGINEERING
COLLEGE: ENGINEERING
COURSE CODE: GST 115
CATEGORIES OF COMPUTER HARDWARE
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Central Processing Unit (CPU)
Input Devices
Output Devices
Secondary Storage Devices
Main Memory (Primary Storage)
Network Hardware.
INPUT DEVICES
All computer hardware components that are instrumental in feeding data to a computer
system are categorized as input devices. An input device is any hardware device that sends
data to a computer, allowing you to interact with and control the computer. An input device
can also be defined as a peripheral (piece of computer hardware equipment) used to provide
data and control signals to an information processing system such as a computer or
information appliance. Examples of input devices include keyboards, mice, scanners, digital
cameras and joysticks.
Examples:
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Audio conversion device
Barcode reader
Biometrics (e.g. fingerprint scanner)
Business Card Reader
Digital camera and Digital Camcorder
Electroencephalography (EEG)
Gamepad, Joystick, Paddle and Steering wheel
Gesture recognition
Graphics tablet
Keyboard
Light gun and light pen scanner
Mouse
Magnetic-stripe reader
CENTRAL PROCESSING UNIT (CPU):
A central processing unit (CPU) is the electronic circuitry within a computer that carries out
the instructions of a computer program by performing the basic arithmetic, logical, control
and input/output (I/O) operations specified by the instructions. The CPU is divided into two:
The Arithmetic and Logical Unit (ALU) and the Control Unit (CU). Sometimes referred to
simply as the central processor, but more commonly called processor, the CPU is the brains
of the computer where most calculations take place. In terms of computing power, the CPU is
the most important element of a computer system.
THE ARITHMETIC AND LOGIC UNIT (ALU): This is a digital circuit within the
processor that performs integer arithmetic and bitwise logic operations. The inputs to the
ALU are the data words to be operated on (called operands), status information from previous
operations, and a code from the control unit indicating which operation to perform.
Depending on the instruction being executed, the operands may come from internal CPU
registers or external memory, or they may be constants generated by the ALU itself.
When all input signals have settled and propagated through the ALU circuitry, the result of
the performed operation appears at the ALU's outputs. The result consists of both a data
word, which may be stored in a register or memory, and status information that is typically
stored in a special, internal CPU register reserved for this purpose.
The Control Unit of the CPU contains circuitry that uses electrical signals to direct the entire
computer system to carry out stored program instructions. The control unit does not execute
program instructions; rather, it directs other parts of the system to do so. The control unit
communicates with both the ALU and memory.
OUTPUT DEVICES:
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) which converts the electronically generated information into human-readable
form.
These examples of output devices also include input/output devices:
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Speakers
Headphones
Screen (Monitor)
Printer
Voice output communication aid
Automotive navigation system
Braille embosser
Projector
Plotter
Television
Radio
Steam
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Wireless
Earphones
SECONDARY STORAGE DEVICES:
Alternatively referred to as external memory, secondary memory, and auxiliary storage, a
secondary storage device is a non-volatile device that holds data until it is deleted or
overwritten. Secondary storage is about two orders of magnitude cheaper than primary
storage. Consequently, hard drives (a prime example of secondary storage) are the go-to
solution for nearly all data kept on today's computers.
Secondary storage devices can be divided into three:
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Magnetic Media: Magnetic storage is the storage of data on a magnetized medium.
Magnetic storage uses different patterns of magnetization in a magnetisable material to
store data and is a form of non-volatile memory. Examples of magnetic storage media
include floppy disks, magnetic recording tape, hard disk and magnetic stripes on credit
cards.
Optical Media: Optical media - such as the compact disk (CD) - are storage media that
hold content in digital form and that are written and read by a laser; these media include
all the various CD and DVD variations, as well as optical jukeboxes and auto changers.
Optical media have a number of advantages over magnetic media such as the floppy disk.
Optical disk capacity ranges up to 6 gigabytes; that's 6 billion bytes compared to the 1.44
megabytes (MB) - 1,440,000 bytes - of the floppy. One optical disk holds about the
equivalent of 500 floppies worth of data. Durability is another feature of optical media;
they last up to seven times as long as traditional storage media. Examples include the CD
and the DVD.
Semiconducting Media: They are also known as flash memory. They use semi-conductor
clips to store data. They are very reliable and durable. They are silent in operation and
they are used in portable devices such as digital cameras, PDA and MP3. Examples are
Compact flash card and Secure Digital Card.
MAIN MEMORY: Main memory is where programs and data are kept when the processor
is actively using them. When programs and data become active, they are copied from
secondary memory into main memory where the processor can interact with them. A copy
remains in secondary memory.
Main memory is intimately connected to the processor, so moving instructions and data into
and out of the processor is very fast. Main memory is where programs and data are kept when
the processor is actively using them. When programs and data become active, they are copied
from secondary memory into main memory where the processor can interact with them. A
copy remains in secondary memory. Main memory can be divided into three;
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Random Access Memory (RAM): Random-access memory is a form of computer data
storage. A random-access memory device allows data items to be accessed (read or
written) in almost the same amount of time irrespective of the physical location of data
inside the memory. In contrast, with other direct-access data storage media such as hard
disks, CD-RWs, DVD-RWs and the older drum memory, the time required to read and
write data items varies significantly depending on their physical locations on the
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recording medium, due to mechanical limitations such as media rotation speeds and arm
movement delays.
Read Only Memory (ROM): Read-only memory is a class of storage medium used in
computers and other electronic devices. Data stored in ROM can only be modified
slowly, with difficulty, or not at all, so it is mainly used to distribute firmware (software
that is very closely tied to specific hardware, and unlikely to need frequent updates).
Complementary metal–oxide–semiconductor (CMOS): This is a technology for
constructing integrated circuits. CMOS technology is used in microprocessors,
microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also
used for several analog circuits such as image sensors (CMOS sensor), data converters,
and highly integrated transceivers for many types of communication. Complementary
metal-oxide semiconductor, or CMOS, typically refers to a battery-powered memory chip
in your computer that stores startup information. Your computer's basic input/output
system (BIOS) uses this information when starting your computer.
NETWORK HARDWARE: Networking hardware may also be known as network
equipment or computer networking devices. Network hardware is the individual components
of a network system that are responsible for transmitting data and facilitating the operations
of a computer network. Although a network contains many hardware components, there are
several basic categories that make up the complete operations of a network system. Examples
include; routers, bridges, network interface card, gateways, hubs, modem and so on.