This document provides an overview of the components and functions of a personal computer. It begins by outlining the objectives and introducing PCs as single-user microcomputers designed for desktop use. It then describes the basic components of a PC including the motherboard, CPU, RAM, storage devices, ports, and peripherals. Finally, it discusses the key functions of PCs as input, output, storage, and processing and provides examples of how these functions work together.

1. MODULE 1/UNIT 1
BY KENNETH AYEBAZIBWE
256774185458 / 256702555890

2. Objectives
• On completion of this unit, you will be able to;
– Identify the components that make up a personal
computer
– Describe the functions and capabilities of
input/output ports
– Add or Remove peripheral devices

3. Introduction to the PC
• A PC is a microcomputer. A PC is a single-user
system, designed to fit on a desk-top; hence the
word Personal. The IBM PC was introduced in the
early eighties and since then has been modified and
improved. Subsequent PCs have been designed to
run any software written for previous versions of
the PC. Many other manufacturers have produced
compatible computers; that is, computers which work
in the same manner as the IBM PC and use the
same software. These are often known as clones.

4. How Bits and Bytes Work
• If you have used a computer for more than five minutes, then
you have heard the words bits and bytes. Both RAM and hard
disk capacities are measured in bytes, as are file sizes when you
examine them in a file viewer.
• You might hear an advertisement that says, "This computer has a
32-bit Pentium processor with 64 megabytes of RAM and 2.1
gigabytes of hard disk space."

5. Decimal Numbers
• The easiest way to understand bits is to compare them to
something you know: digits. A digit is a single place that
can hold numerical values between 0 and 9. Digits are
normally combined together in groups to create larger
numbers. For example, 6,357 has four digits. It is
understood that in the number 6,357, the 7 is filling the
"1s place," while the 5 is filling the 10s place, the 3 is
filling the 100s place and the 6 is filling the 1,000s place.
So you could express things this way if you wanted to be
explicit:
• (6 * 1000) + (3 * 100) + (5 * 10) + (7 * 1) = 6000 + 300
+ 50 + 7 = 6357

6. • Another way to express it would be to use
powers of 10. Assuming that we are going to
represent the concept of "raised to the power
of" with the "^" symbol (so "10 squared" is
written as "10^2"), another way to express it is
like this:
• (6 * 10^3) + (3 * 10^2) + (5 * 10^1) + (7 *
10^0) = 6000 + 300 + 50 + 7 = 6357

7. • What you can see from this expression is that each digit is a
placeholder for the next higher power of 10, starting in the first digit
with 10 raised to the power of zero.
• ­That should all feel pretty comfortable -- we work with decimal digits
every day. The neat thing about number systems is that there is nothing
that forces you to have 10 different values in a digit. Our base-10
number system likely grew up because we have 10 fingers, but if we
happened to evolve to have eight fingers instead, we would probably
have a base-8 number system. You can have base-anything number
systems. In fact, there are lots of good reasons to use different bases in
different situations.
• Computers happen to operate using the base-2 number system, also
known as the binary number system (just like the base-10 number
system is known as the decimal number system)

8. • Different units are used to describe file sizes and
memory capacity
– 8 bits form a byte (B)
– 1024 bytes make a kilobyte
– 1024 kilobytes(KB) make a megabyte (MB)
– 1024 MB makes 1 Gigabyte (GB)
– 1024 GB makes 1 Terabyte (TB)

9. Key functions of a PC
• Before learning how to use a computer, you must first learn the
different functions that a computer can perform. Basically, there are
four functions, input, output, storage, processing.
– Input
Computer can keep track of any different types of information. With
software like Microsoft word, notepad. it makes inputting any data such
as words, articles relatively easy. Examples of input devices include, your
keyboard, computer mouse, microphone etc.
– Processing
Computer can rapidly solve all types of numerical problems. Solving
numerical problems can be considered as an example of computer
processing. With the ability of data manipulation of company, task can be
completed efficiently with effectively. Saving lots and lots of time and
effort, compared to human work. Aslo, computer are accurate and error
free, they can process huge amount of information at the same time and
they inexpensive.

10. – Storage
Imagine you have a collections of ten thousand photos. You are going to
london to meet your relative and were told to bring that ten thousands
photos over. Guess what? That is alot of things. So with the advent of
computer, you can just save that ten thousand photos and bring your
laptop over. That’s that simple!. Example of computer storage include,
harddisk, cd rom, dvd rom and others.
– Output
Output is one of the most commonly used function in computer. It may
refers to the graph that is being plotted in microsoft excel, the song that
you are playing from media player, the powerpoint slide, So if anyone ask
you, what is the basic functions of computer, always remember the below
story. “I am plotting a graph in microsoft excel, i am entering the values
(input), the computer will calculate the values and plot the graph for me
(processing), then display the graph (output), and after that, i will save it
(storage) in my hardisk.

11. Personal computer hardware
• Personal computer hardware are the component
devices that are the building blocks of personal
computers. These are typically installed into a
computer case, or attached to it by a cable or
through a port. In the latter case, they are also
referred to as peripherals.

13. Hardware of a modern personal
computer
1. Monitor
2. Motherboard
3. CPU
4. RAM
5. Expansion cards
6. Power supply
7. Optical disc drive
8. Hard disk drive
9. Keyboard
10. Mouse

14. Computer Case
– A computer case (also known as a computer chassis, cabinet, box, tower,
enclosure, housing, system unit or simply case) is the enclosure that contains most
of the components of a computer (usually excluding the display, keyboard and
mouse). A computer case is sometimes incorrectly referred to metonymously as a
CPU referring to a component housed within the case. CPU was a common term
in the earlier days of home computers, when peripherals other than the
motherboard were usually housed in their own separate cases.
Power supply
A power supply unit (PSU) converts alternating current (AC) electric power to low-
voltage DC power for the internal components of the computer. Some power
supplies have a switch to change between 230 V and 115 V. Other models have
automatic sensors that switch input voltage automatically, or are able to accept
any voltage between those limits. Power supply units used in computers are nearly
always switch mode power supplies (SMPS). The SMPS provides regulated direct
current power at the several voltages required by the motherboard and accessories
such as disk drives and cooling fans.

15. • Motherboard
• The motherboard is the main component inside the case. It is a large
rectangular board with integrated circuitry that connects the other parts
of the computer including the CPU, the RAM, the disk drives (CD,
DVD, hard disk, or any others) as well as any peripherals connected via
the ports or the expansion slots.
• Components directly attached to the motherboard include:
– The CPU (Central Processing Unit) performs most of the calculations
which enable a computer to function, and is sometimes referred to as the
"brain" of the computer. It is usually cooled by a heat sink and fan. Most
newer CPUs include an on-die Graphics Processing Unit (GPU).
– The Chipset, which includes the north bridge, mediates communication
between the CPU and the other components of the system, including
main memory.
– The Random-Access Memory (RAM) stores the code and data that are
being actively accessed by the CPU.

16. • The Read-Only Memory (ROM) stores the BIOS that runs when the
computer is powered on or otherwise begins execution, a process
known as Bootstrapping, or "booting" or "booting up".
• The BIOS (Basic Input Output System) includes boot firmware and
power management firmware. Newer motherboards use Unified
Extensible Firmware Interface (UEFI) instead of BIOS.
– Buses connect the CPU to various internal components and to expansion
cards for graphics and sound.
• Current
• PCI Express: for expansion cards such as graphics, sound, network interfaces, TV
tuners, etc.
• PCI: for other expansion cards.
• SATA: for disk drives.

17. • Ports for external peripherals. These ports may
be controlled directly by the south bridge I/O
controller or provided by expansion cards
attached to the motherboard. USB
• Memory Card
• FireWire
• eSATA
• SCSI

18. • Expansion Cards
– The 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 or backplane to add functionality to a computer
system via the expansion bus.
– An example of an expansion card is a sound card that enables
the computer to output sound to audio devices, as well as
accept input from a microphone. Most modern computers
have hardware support for sound integrated in the
motherboard chipset but some users prefer to install a
separate sound card as an upgrade. Most sound cards, either
built-in or added, have surround sound capabilities and 3-D
sound effects.

19. • Secondary Storage Devices
– Computer data storage, often called storage or memory, refers to computer components and
recording media that retain digital data. Data storage is a core function and fundamental
component of computers.
• Fixed Media Devices
• Hard disk drives: a hard disk drive (HDD; also hard drive, hard disk, or disk drive)[2]
is a device for storing and retrieving digital information, primarily computer data. It
consists of one or more rigid (hence "hard") rapidly rotating discs (often referred to as
platters), coated with magnetic material and with magnetic heads arranged to write
data to the surfaces and read it from them.
• Solid-state drives: a solid-state drive (SSD), sometimes called a solid-state disk or
electronic disk, is a data storage device that uses solid-state memory to store persistent
data with the intention of providing access in the same manner of a traditional block
I/O hard disk drive. SSDs are distinguished from traditional magnetic disks such as
hard disk drives (HDDs) or floppy disk, which are electromechanical devices
containing spinning disks and movable read/write heads.
• RAID array controller - a device to manage several internal or external hard disks and
optionally some peripherals in order to achieve performance or reliability
improvement in what is called a RAID array.

20. • Removable Media Devices
– Optical Disc Drives for reading from and writing to various kinds
of optical media, including Compact Discs such as CD-ROMs,
DVDs, DVD-RAMs and Blu-ray Discs. Optical discs are the most
common way of transferring digital video, and are popular for data
storage as well.
– Floppy disk drives for reading and writing to floppy disks, an
outdated storage media consisting of a thin disk of a flexible
magnetic storage medium. These were once standard on most
computers but are no longer in common use. Floppies are used
today mainly for loading device drivers not included with an
operating system release (for example, RAID drivers).
– Zip drives, an outdated medium-capacity removable disk storage
system, for reading from and writing to Zip disks, was first
introduced by Iomega in 1994.

21. – USB flash drive plug into a USB port and do not require a separate
drive. USB flash drive is a typically small, lightweight, removable,
and rewritable flash memory data storage device integrated with a
USB interface. Capacities vary, from hundreds of megabytes (in the
same range as CDs) to tens of gigabytes (surpassing Blu-ray discs
but also costing significantly more).
– Memory card readers for reading from and writing to Memory
cards, a flash memory data storage device used to store digital
information. Memory cards are typically used on mobile devices.
They are thinner, smaller and lighter than USB flash drives.
Common types of memory cards are SD and MS.
– Tape drives read and write data on a magnetic tape, and are used
for long term storage and backups.

22. Review Questions
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