Fundamentals of Hardware and
Software
1
What is a computer?
• A computer may be define as an electronic
device which accepts input, processes the input
and produces results (output) from the
processing and store data for future use.
2
What are the main component of a computer system
⚫ Hardware- Physical parts of a computer that you
can see and touch.
⚫ Input devices- They get data into a computer.
E.g. keyboard, mouse, scanner.
⚫ CPU-(Central Processing Unit)- This is the
brain of the computer and controls how the rest
of the computer works.
3
Cont’d
⚫ Output devices- They get processed information
out of a computer. e.g. printer, monitor, speakers.
⚫ Storage Devices- Devices used for storing
information permanently. E.g. hard disk drive,
CDROM drives, flash drives, floppy drive.
⚫ Memory-enables a computer to temporarily store
instructions and data
4
Explain the functions of the major hardware
components of the computer system
⚫ Control Unit- This is part of the CPU responsible
for fetching and executing programmed
instructions used to operate the computer.
⚫ ALU(Arithmetic Logic Unit)- Responsible for
performing all the tasks pertaining to arithmetic.
⚫ Secondary Storage- Also known as auxilliary
storage, this memory is external, where it stores
programs and data for future use
5
Outline the functions and use of Primary
Storage Devices
• Bistable Devices-a device that can exist in one of two
possible states. It can be compared to an on/off switch.
• PROM(Programmable Read Only Memory)
Once programmed cannot be erased.
• EPROM(Erasable Programmable Read Only Memory-)
erased by exposure to ultra-violet lights.
• EEPROM - (Electrically Erasable Programmable Read
Only Memory) erased by exposure to electrical charge
6
Cont’d
⚫ RAM (Random Access Memory)-Contains
temporary or volatile memory which is lost
(erased) when the computer's power supply is
turned off.
⚫ ROM-Read Only Memory
A memory chip that stores instruction and data
permanently. Contents are non-volatile (not lost
when the computer's power supply is lost).
7
Cont’d
⚫ Megabyte- A megabyte is 2 to the 20th power, or
1,048,576 bytes.
⚫ Gigabyte-The equivalent of approximately one
billion bytes
⚫ Terabyte- A terabyte is 2 to the 40th power, or
1,099,511,627,776 bytes.
⚫ Kilobyte-One thousand and Twenty-four bytes.
(1024 Bytes)
8
Compare the types of secondary storage media with
respect to portability, speed and capacity
• Magnetic tape
A magnetic tape is a tape coated with a
magnetic material on which data can be
stored. This is a sequential access storage
device that is usually used for backup
purposes. Types of magnetic tapes include
cassette, cartridge and reel.
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• Floppy disk -This is a removable disk that has
a small storage capacity; it is typically used to
store documents so it can be used on more
than one computer. Diskettes are normally used
to store backup copies of important information.
Diskettes are available in two sizes: 51/2 and
31/2 .
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• Hard disks/hard drive - This is normally
permanently installed and fixed into the
computer. However, there are external hard
drives available. A hard drive can access data
much more quickly than floppy disk drive; most
importantly, it can store much more data.
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• Flash drives - are data-storage devices
integrated with a USB (universal serial bus)
interface. They are generally 7mm in length and
weigh less than two ounces, making them the
perfect portable storage device. Storage ranges
from 64MB to 64 GB.
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• FLASH MEMORY- is a non-volatile computer
memory that can be electrically erased and
reprogrammed. It is a technology that is
primarily used in memory cards and USB flash
drives for general storage and transfer of data.
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Menu Driven
• The user is presented with a choice and, therefore, does not
have to remember any commands. The interface is,
therefore, suitable for beginners and infrequent users.
• Pull-down menu: one that opens immediately below the
position of your mouse (or other pointing device). You move
the cursor downward to go through the items in the menu
list.
• Pop-up menu: any menu list that pops
• up on the screen, on demand, to offer
• you a choice of commands.
14
Cont’d
Advantage of menu-driven interfaces
• The user is presented with a list of options to choose from,
they do not need to remember the commands.
• Disadvantage of menu-driven interface
• Several steps required to issue a command.
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