Download input devices

NAME: UNUEBHOLO EMMANUEL OSEREME
COLLEGE: ENGINEERING
DEPARTMENT: PETROLEUM ENGINEERING
LEVEL: 100LEVEL
COURSE CODE: GST 115
CATEGORIES OF COMPUTER HARDWARE
1. Central Processing Unit (CPU)
2. Input Devices
3. Output Devices
4. Secondary Storage Devices
5. Main Memory (Primary Storage)
6. 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. The
picture shows a Logitech trackball mouse, an example of an input device. 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:

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:

Speakers

Headphones

Screen (Monitor)

Printer

Voice output communication aid

Automotive navigation system

Braille embosser

Projector

Plotter

Television

Radio

Steam

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:

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 semiconductor 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;

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 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 batterypowered 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.