Download 1. The Central Processing Unit (CPU)

NAME: OLUWATAYO OLUWASEYI TOLUWALASE
DEPARTMENT: MEDICINE AND SURGERY
COURSE: GST 115
ASSIGNMENT: LIST AND DISCUSS THE SIX CATEGORIES OF COMPUTER HARDWARE
1. Central Processing Unit (CPU)
2. Main Memory.
3. Secondary Storage
4. Input Devices
5. Output Devices
6. Connectivity Hardware
1. The Central Processing Unit (CPU):
The CPU is the most important component of a computer system. It is the brain of
the computer system and it determines the capacity of the compute system. It connects
other components and directs them according to the available program. All other
hardware components of computer system connect to CPU in order to carry out
instructions. These other components cannot work on their own without the CPU. The
CPU has two major parts, the Arithmetic and Logic Unit (ALU) and the control unit
(CU).These two parts of CPU contain registers. Registers are high speed storage location
that temporarily holds data and instructions during processing. The ALU and CU have
different registers with different functions.
The arithmetic and logic unit: this is the part of CPU which handles arithmetic operation
such as addition, subtraction, multiplication and division. It has the ability to carry out
reasoning and decision making, thus performs logical operations such as greater than
(>), less than (<), equal to (=) and not equal to signs. The registers available in ALU are
Adder and Accumulator.
The control unit: the control unit interprets the instructions from the main memory. It
gives instructions to ALU on what operation and how to carry it out. It gives directives to
the peripheral devices of the computer system and it controls all the activities of the
computer. It has three registers which include the following; instruction register,
instruction decoder, program counter.
2. The Main Memory: The main memory is a storage media on the motherboard. It is
used to store data and instructions to be executed by the CPU. Main memory is closer to
the CPU than any secondary storage device, it is the memory that CPU used to access
often and often. The main memory of a computer system can be classified into three
distinct categories which are Random Access Memory, Read only Memory (ROM) and
Complementary Metal oxide semi-conductor memory (CMOS).
Random Access Memory (RAM): it is a volatile type of memory. In case of power failure,
information on RAM is lost. It is a temporary storage medium used to hold the data and
instructions currently working on by the computer system.
Read Only Memory (ROM): it is a non-volatile type of memory. Power failure does not
affect the content or ROM. It allows to read its contents but do not allow the users to
change it or write it. It is used to store permanent instructions and data. ROM is used to
store instructions that control the activities of the computer system.
Complementary metal oxide semi-conductor memory (CMOS): it is a hybrid derived
from the combination of some properties of RAM and ROM. CMOS is non-volatile and
the content can be changed easily. It is often used to store configuration information of
computer system like size of hard disk, current time and date. It doesn’t store any
program.
3. Secondary Storage: the central processing unit can only process data instruction on
RAM. As RAM is volatile what happens to the data processed? The processed data must
be stored in another storage device. Do not think of ROM as the solution as ROM does
not allow users to interact freely, then the need for secondary storage device that user
can easily interact with.
Types of secondary storage
1. Magnetic media: this is a type of secondary storage. It includes the floppy disk,
hard disk, and magnetic tape.
2. Optical media: these are storage media that hold content in digital form and that
are written and read by a laser. These storage media group include all the various
CD and DVD variations.
3. Semi-conducting media: These are often called flash memories. They use semiconductor clips to store data. They are very reliable and durable. They are silent
in operation and they are used in some portable devices such as digital cameras,
PDA and MP3. Examples include: Microdrive (MD), Secure Digital Card(SD card),
compact flash card (Cfcard) and Smart Media Card(SM card).
4. Input devices: input devices are the devices that allow users to enter data and
command into the computer system. Some of these devices are described below.
TYPES OF INPUT DEVICES
1 .Keyboard
2. Moue
3. Joystick
4. Scanner
5. Bar Code Reader
1. Keyboard: A keyboard is a well-known input device which contains alphabets,
numeric/digits, special keys, function keys etc. keyboard can be of serial or parallel.
Alphabets: - A to Z, a to z.
Numeric keys: - 0-9
Special keys: - shift, spacebar, ctr, alt etc.
Functions key: - F1, F2…….F12.
Keyboard is used to convert these above mentioned keys into digital form of
computer.
2. Mouse: A mouse is an input device which is also called a pointing device. It is
used to move the cursor on the screen. Mouse works in GUI (Graphical User
Interface) mode. Mouse is of different types in which some are physical mouse,
optical mouse, and cordless mouse.
3. Joystick: It is also called as game controller device. Joystick is a remote control
device which is used in gaming purpose. We will also play with keyboard but
joystick gives more simplicity and more speed than keyboard.
4. Scanner: Scanner is an example of input device which are mainly used to check
OMR sheets. It is also used to copy text, images in the form of soft copy.
5. Bar Code Reader (BCR): Bar Code Reader is generally used in shopping malls;
BCR read the bar code and display the rate of item on the computer screen. It is
also used to recognize courier products. BCR takes input in the form of code and
convert this bar code into computer language (0 or 1).
5. Output devices: An output is a hardware that presents digital information in form
that human being can understand.
Types of output devices
1. Visual Display Unit (VDU): It is commonly referred to as monitor. There are two
technologies for VDU; (i) cathode ray tubes (CRT).
(ii) Liquid crystal display (LCD).
2. Data projector: it use strong light rays to project the computer display onto a
large screen for a group of people to see. The projectors used in this school are
LCD projector.
3. Printer: it is an output device that output texts and graphics on a physical
medium such as paper or transparency film. The printed information is called the
hardcopy. Printers can be divided into two categories; (i)impact printers which
produces printed images by physically striking pins against an ink ribbon to leave
dots on the paper. Examples include dot-matrix printer. (ii)non-impact printers
which output information on paper without physically striking the paper. There
are 3 types which include; ink-jet printer, laser printer, thermal printer.
4. Speakers
5. Headsets.
6. Computer output or microfilm (COM).
6. CONNECTIVITY HARDWARE: Connectivity hardware is the hardware that allows
computer to be physically connected to different type of networks.
EXAMPLES OF CONNECTIVITY HARDWARE
1. Modem
2. Router
3. Network interface controller
4. Ethernet hub
5. Brouter
1. Modem: A modem (modulator-demodulator) is a device that modulates one or
more carrier wave signals to encode digital information for transmission and
demodulates signals to decode the transmitted information. The goal is to produce
a signal that can be transmitted easily and decoded to reproduce the original
digital data. Modems can be used with any means of transmitting analog signals,
from light emitting diodes to radio. A common type of modem is one that turns the
digital data of a computer into modulated electrical signal for transmission over
telephone lines and demodulated by another modem at the receiver side to
recover the digital data.
2. Router: A router is a networking device that forwards data packets between
computer networks. Routers perform the “traffic directing” functions on the
internet. A data packet is typically forwarded from one router to another through
the networks that constitute the internetwork until it reaches its destination node.
A router is connected to two or more data lines from different networks (as
opposed to a network switch, which connects data lines from one single network).
When a data packet comes in on one of the lines, the router reads the address
information in the packet to determine its ultimate destination. Then, using
information in its routing table or routing policy, it directs the packet to the next
network on its journey. This creates an overlay internetwork. The most familiar
types of routers are home and small office routers that simply pass data, such as
web pages, email.
3. Network interface controller: A network interface controller (NIC, also known as a
network interface card, network adapter, LAN adapter or physical network
interface and by similar terms) is a computer hardware component that connects a
computer to a computer network. Early network interface controllers were
commonly implemented on expansion cards that plugged into a computer bus. The
low cost and ubiquity of the Ethernet standard means that most newer computers
have a network interface built into the motherboard. Modern network interface
controllers offer advanced features such as interrupt and DMA interfaces to the
host processors, support for multiple receive and transmit queues, partitioning
into multiple logical interfaces, and on-controller network traffic processing such
as the TCP offload engine.
4. Ethernet hub: An Ethernet hub, active hub, network hub, repeater hub, multiport
repeater, or simply hub is a device for connecting multiple Ethernet devices
together and making them act as a single network segment. It has multiple
input/output (I/O) ports, in which a signal introduced at the input of any port
appears at the output of every port except the original incoming. A hub works at
the physical layer (layer 1) of the OSI model. Repeater hubs also participate in
collision detection, forwarding a jam signal to all ports if it detects a collision. In
addition to standard 8P8C (‘’RJ45’’) ports, some hubs may also come with a BNC or
Attachment unit interface (AUI) connector to allow connection to legacy 10BASE2
or 10BASE5 network segments.
5. Brouter: A brouter (pronounced BRAU-tuhr or sometimes BEE-rau-tuhr) is a
network bridge and a router combined in a single product. A bridge is a device that
connects on local area network (LAN) to another local area network that uses the
same protocol (for example, Ethernet or token ring). If a data unit on one LAN is
intended for a destination on an interconnected LAN, the bridge forwards the data
unit to that LAN; otherwise, it passes it along the same LAN. A bridge usually offers
only one path to a given interconnected LAN. A router connects a network to one
or more other networks that are usually part of a wide area network (WAN) and
may offer a number of paths out to destinations on those networks.