Lecture note on computer hardware

1. Introduction to Computer
Hardware
Elike Ike

2. Introduction
"Hardware" What does this word sound like? It gives the
impression of something strong and solid, right? That is
for the hard part of it. What about the "ware" part of the
term?
Computer hardware are the solid components in a
computer that enables the computer carry out the
various functions we assign to it. They can be seen and
touched as solid components inside the computer. These
components found in a computer are assembled
together to form a system, that is, they are the building
blocks of a computer system, just like the human
nervous system.

3. The computing function is divided into three broad areas, these are
input, processing and output. There are sets of hardware devices that
work to make these three functions possible.
•keyboard
•Scanner
•Mouse
•microphone
Input
•CPU
•GPUProcessing
•monitor
•Printer
•Speaker
Output

4. Input Device
• Keyboard
This is an interface through which values are sent to
the computer by making keystrokes. Most
keyboards are alphanumeric, that is they contain
both alphabets and numbers. Today, we have a
large variety of keyboards due to the different types
of computer devices and their form factor.
The standard keyboard is one that has all the
alphanumeric keys and function keys but it is
without multimedia, office and Internet keys. It
comes with 84 keys while the enhanced keyboard
which comes with additional keys for mathematical
operations has keys ranging from 101 to 105.

5. Input Device
• Mouse
These are small handheld pointing and navigating devices used for
selecting items or passing push commands on the computer screen. It
moves a corresponding arrow on the screen called cursor. The process
of selecting text items on the screen is called highlighting while the
process of passing instructions by pushing on items is called clicking.
Hovering the mouse across items on display is called mouse over.
For touch screen devices, stylus pens like Pencil by fiftythree and even
our fingers can serve as input devices replacing the roles of the mouse
with various gestures.

6. • Microphone
These are audio recording/transmitting devices. They are a
common feature in modern laptop computers used for
converting audible wave signal to digital form. Microphones
can be embedded or attached to a computer to enable it
record and transmit voice, take dictation or pass voice
commands.
With Apple’s Siri and Microsoft’s Cortana you can ask your
mobile devices "real life" questions and it will provide
answers, you can make Internet searches, dictation, book
reservations and schedule calendar events simply by using
your voice to instruct the device.
Input Device

7. Input Device
• Scanner
This is a device used to produce digital copies of paper
documents and pictures by processing them through a
process known as optical character recognition (that is
reading and recognizing text and picture elements on a
hard copy document). There are various types of
scanners today. The most common ones are the
flatbed, sheet fed, handheld and drum scanners.
people to use the high resolution cameras in their
mobile devices to snap documents as an alternative to
scanning. Then software like ABBYY Reader can be used
for digital character recognition.

8. Input Device
• Camera
This is a photographic imaging device used to
record/transmit images and motion pictures. It is
commonplace to see cameras in laptop computers and
mobile devices such as tablet PCs and smartphones.
Cameras can be used to record real life events for YouTube
upload or for use in blogs. They are also used for video calls
and chatting and teleconferencing through Skype or
FaceTime.

9. PROCESSING UNIT
This is the part of the computer where the inputs received are analyzed
and processed digitally before outputs are generated. It is analogous to
the brain of human that processes all the stimulus generated by the
sense organs. In this area, we will be looking at the central processing
unit, read only memory, random access memory, graphic processing
unit and the motherboard.

10. Processor
Often referred to as the central processing unit, the processor is
a tiny bunch of transistors spurn on a chip that handles the
calculation and processing of data in the computer system. The
transistor handles instructions and data in bits and some
processors can handle several thousands of bits in one second.
Because the development of processor has a mathematical
foundation, it handles every information in a mathematical
manner such as multiplication, addition, subtraction etc, it also
moves data from one location to another or cycle through series
of instructions in split seconds.
Intel 4004, they have come up with innovative ways to increase
the computing speed with ranges of processors from the singles
Core Pentium, to the dual-cores, then quad and now core i3, i5
and i7. Generally, the speed of the processor in general is
dependent on how many millions of instructions per second
(MIPS). This is affected by the number of cores and their clock
speed.
The processor works with the ROM and RAM.

11. Read Only Memory (ROM)
The rom is a memory module connected
through a bus to the processor. The processor
can only fetch information from the rom but
cannot write to the rom, that why it is called
read only. Rom is needed when the computer
starts up as it holds the information for Basic
Input and Output System (BIOS). The
information stored in the rom is permanent.
The bios information also controls the
operations and transfer of data between the
operating system and connected devices, like
mouse and printers.

12. Random Access Memory (RAM)
This is a memory module that holds data in place for the processor
such that the processor can read from and write to it in quick
succession. The ram is very vital as it stores data which enables the
processor carry out multiple instructions within seconds. In fact, the
memory capacity of the ram can affect a processor's level of
multitasking. So if the ram storage capacity is low, the computer
become slow when multiple applications are being used at the same
time. However, for most computers the ram can be increased to
optimize system performance.

13. Graphic Processing Unit (GPU)
This is a single chip processor used mainly to aid the
processing of graphical contents like videos and
pictures. GPU-accelerated computing dramatically
increases the performance of a computer by reducing
the workload on the CPU allowing the GPU do the
tasks. The GPU process the heavy tasks while the CPU
process the codes making the computer run super fast.
Nvidia (2015), the company that pioneered GPU
technology in 2007, "a simple way to understand the
difference between a CPU and GPU is to compare how
they process tasks. A CPU consists of a few cores
optimized for sequential serial processing while a GPU
has a massively parallel architecture consisting of
thousands of smaller, more efficient cores designed for
handling multiple tasks simultaneously".

14. Graphic Processing Unit (GPU)
Nowadays, CPUs and GPUs are merged together in a single chip in
some devices to form what is known coprocessor, an example is the
iPad Air2 A8X chip that adds the M8 Motion power to boost the
graphical performance of the iPad and at the same time increase its
speed and power performance.

15. Motherboard
Simply put, the motherboard is the platform that connects all the devices in
the computer. It is a digital electronic field where connected circuits are
printed and cables linking one component of the computer to another and
keeping all of them in place so that they do not fall off.
The input devices, processors,
output device and storage
devices are all linked on the
motherboard. It is also known
as the logic board or main
board or system board.

16. STORAGE DEVICES
These are devices used to store raw data to be used while working with
the computer or information generated from the computer. Every
computer needs a storage device apart from the RAM which is the
computer's main memory. Storage devices are used to keep application
programs and user files like documents, pictures, music and movies.
The files stored in the computer are stored as binary digits of 1s and 0s.
The digits put together in various possible combinations form a file and
the amount of digits in that combine to form the file determines the
amount of storage space the file will occupy in the storage device.

17. STORAGE DEVICES
There are standard units for measuring the amount of memory a file is
taking in memory or the file size based on the binary combination. A
digit consisting of either one of two possible states (values) of on (1)
and off (0) forms a bit. A bit is the basic unit of information in the
digital sphere. Eight (8) bits form one byte. The table below explains
further the various units of data measurements.
Bit Byte Kilobyte Megabyte Gigabyte Terabyte
Bit 1
Byte 8 1
Kilobyte 8,192 1,024 1
Megabyte 8,388,608 1,048,576 1,024 1
Gigabyte 8,589,934,592 1,073,741,824 1,048,576 1,024 1
Terabyte 8,796,093,622,000 1,099,511,628,000 1,073,741,824 1,048,476 1,024 1

18. Types of Storage
There are different types of storage devices and while some do reside
within the computer(internal memory), others are attached to it
externally, thus they are referred to as External Memory. Storage
devices in computer are often referred to as drives or storage media.
Basically, in computer there are three major types of memory when
looking at how they operate. These are Hard Disk Drive, Solid State
Memory and Optical Drive. These three broad categories have their
subcategories.

19. Hard Disk Drive (HDD)
This drive store data on a circular rotary metal
plate. The plate is usually encased in a rubber or
metal container to prevent it from scratch or
shocks due to movement of the computer. The
data is read from the surface which is divided into
very tiny units known as tracks and sectors. The
tracks go round the entire disk forming series of
circles and they are divided by the sectors to form
tiny units where information is stored.
Often, they are used as internal memory for the
computer but they can also be put in solid cases
with relevant connectors like USB to enable them
interface with the computer as external drives.

20. Optical Disc Drives
These storage devices hold files in tiny bumps and dips on a
reflective (coated with reflective dyes) surface. The data stored on
the disc is read or written with tiny laser beams from a lens which
transfer the data as simple zeros and ones for the computer to
process.
There are four (4) common types of optical disc drives and they all
have varying amount of data that they can hold (storage capacity).
These are:
1. Mini disc drive (177mb can record audio for 80mins and HD
MiniDisc version with 1gig can record up 45hours at 48kbs),
2. Compact Disc (700mb of data can record up to 80mins),
3. Digital Video/Versatile Disc (4.7gig on a single layer and
15.09gig on a double layered disc).
4. Blu Ray Disc (25gig on single layer, 50 on double layer, 100gig on
triple layer and 128gig on a quadruple layered disc).

21. Solid State Drive
These storage devices have no moving parts.
The data are stored in integrated circuits, so
they have no disc neither do they need lasers.
They come in form of card or block memory,
hence the name solid state. The data stored in
them are often read/written with the use of
card readers. The advantage of this form of
data storage are one, they have a very high
read and write rate and two, they are not
susceptible to shock.

22. OUTPUT DEVICES
These are devices that give us the information the computer generated
after processing data. They can show us outcome, result and processes
of what the computer does with data. Some of the major forms of
output devices are the computer display unit (monitor), printer and
speaker. Let us look at each of these forms of output.

23. Monitor
This can be a screen device that displays text and graphics
through which we know what the computer is doing. But
with the advancement of technology today, the small
screens of some mobile devices which serves as output
device also serve as input devices as they come with
touchscreen keyboard options. Some good examples are
the Samsung Galaxy Note and the Apple IPad. It is
important to note here that, the display does not always
relate to a graphical screen as a simple LED display board
and digital clock display also represent monitors based on
the device form factor. The basic idea in monitor is that light
is used in some ways to relate information from a computer
device to the user.

24. Printer
While the monitors tend to be printing on screen
with the aid of light, the printer prints on paper with
the aid of ink. The output can be in color, greyscale
or black and white depending on the type of printer
and the source document being printed or what is
desired by the user.
This is a device that displays the information generated from a computer by
writing with ink on paper. Printers can give very detailed drawing of art,
architectural sketches, lines representative of brainwave from an
electroencephalogram or the picture of real people.

25. Speaker
An online phone call or streaming media
will likely generate a voice sound while an
error in data entry can generate a beep
sound to notify the user or someone
nearby. With midi devices, musical sound
can be generated on the computer for
general enjoyment.
This device outputs basically sound wave which are audible to the human
ear as a result of data being processed. This kind of sound can be a beep,
a voice or music depending on the type of data being processed.

26. PORTS
These are sockets for connecting devices to computer or connecting
the computer to other devices in order to extend the functionality of
the computer or simply for the purpose of sharing information.
Basically, ports provide some form of signal or data transfer between
the connected devices.
Most devices have more than one port, depending on what they are
used for. For desktop computers, the ports are usually located at the
back of the computer main unit, while for laptops the ports are often at
the sides like wise for tablets and smartphones. Here we will look at
some of the common ports found in computers such as:
USB, HDMI, LAN, VGA, and FireWire ports.

27. USB (Universal Serial Bus)
This by far the most commonly used ports on the computer as majority
of devices use it as their standard for interfacing with computers. The
first USB port was designed in 1996 as a way of creating a standard way
of connecting peripheral devices to computers. Today, they only help in
the transfer of data but are also capable of charging small connected
devices like smartphones and tablets by supplying 5volts (1.8amps)
electric power to the device. The four pin USB connector uses one pin
for power supply, two for data and the other one for grounding (to
provide earth).
There are versions of USB, that version 1.x, 2.0, 3.0, 3.1 and USB Type-
C.

28. USB Transfer Rates
Standard Transfer rate
USB 1.0 1.5mbps
USB 2.0 480mbps
USB 3.0 5gbps
USB Type-C 10gbps
The USB Type-C also has increased power supply of
up to 20volts and 5amps.

29. HDMI (High Definition Multimedia Interface)
This port is used to transfer high quality multimedia contents.
It conveys uncompressed video and audio contents especially
for display purposes. In some cases, it carries along device
property enabling the other device to access and control the
source of the media contents. It is proprietary, that is, it is
distributed under license as a standard port. HDMI has can
popularity in consumer electronics as a way of connecting
high definition video players such as BluRay players to their
high definition or 4k displays to get excellent color rendition.
Just a single cable transfers the audio and video. It is now
being widely used to connect computers to projectors and
other external displays. HDMI can connect with DVI but
cannot interface with VGA because it has no analog signal.

30. DVI (Digital Visual Interface)
It is primarily a video display interface, connecting a device to a display
unit. The DVI is compatible with HDMI in that you can convey an HDMI
content to DVI outlet without conversion. The 29 pin DVI because of its
versatility can also send and receive analog signal making it compatible
with VGA connection.

31. VGA (Video Graphics Array)
This is a fifteen pin analog cable used to transfer visual contents. These
cables have been used in computers since 1987 and currently is used in
modern televisions as alternative port. The VGA can only carry video
and no audio. Audio is usually passed through a pin connector that
interfaces with the audio jack of the speaker device or same display
unit. DVI can be connected and converted to VGA.

32. LAN (Local Area Network)
This port also known as Ethernet port is used to connect computers
within a specified area like home, office or school such as Ethernet. It
can be used to share data, share Internet access or share resources like
printers and scanners. The cable often referred to as Category 5 cable is
a twisted pair. The maximum length of a single of this cable is 100m.

33. FireWire
Also known as i.Link or as IEEE 1394, the
FireWire was designed by Apple in 1995 to
enhance data transfer and connectivity
between devices. It was widely used by Sony
for the transfer of video contents from its
cameras and video tape machines to
computer due to its high rate of data transfer
800mbs. It was made hot pluggable such that
it can be connected and disconnected while
the machine still runs. These cable offer low
cost data transfer and plug-and-play.

34. Next Class…
Software – Operating Systems
and Applications