ICTlecture2 for 1st Semester Students of BS(CS)

ICT Lecture 02

1. APPLICATIONS OF INFORMATION AND
COMMUNICATION TECHNOLOGY (ICT)
Ms. Saba Shams
Lecture#2

2. Computer Hardware:
A computer system comprises various components, with those that are visible and tangible referred to as
computer hardware. In simple terms, hardware refers to the physical equipment that helps the computer
work. The main categories of computer hardware are:
•Processing Devices
•Memory Devices
•Input/OutputDevices
•Storage Devices

3. Computer hardware:

4. Processing devices:
•The Central Processing Unit (CPU) is an electronic device that runs computer programs, which are sets
of instructions. We consider the CPU as the processing device of the computer . Often called the "brain"
of the computer, the CPU consists of two main parts: the Control Unit (CU) and the Arithmetic and
Logic Unit (ALU).
•Control Unit : A computer program or set of instructions must be stored in memory for a computer to
process data. The CPU uses its CU to execute these instructions. Further, the CU directs and coordinates
most of the operations of the computer. The speed at which the processor carries out its operations is
measured in megahertz (MHz). The higher the number of MHz the faster the computer can process
information. The Intel i7, Athlon, and Duron, Ultra Spark are some examples for the brands of processors.

5. Processing devices:
The Arithmetic and Logic Unit (ALU) : ALU performs the arithmetic, comparison, and logical operations.
Arithmetic operations include addition (+), subtraction (-), multiplication (*) and division (/). Comparison
operations include comparing one data item to another to determine if the first item is greater than (>), equal
(=), or less than (<) to the second item. Logical operations work with conditions such as AND, OR, NOT.

6. Memory Devices:
A character in a computer is stored as a group of 0s and 1s, called a byte. The amount of memory a com
puter has is measured in bytes. Bit is the smallest unit of data. Here are the units for measuring memory:
•8 bits = 1 byte
•1024 bytes = 1 Kilobyte (KB)
•1024 KB = 1 Megabyte (MB)
•1024 MB = 1 Gigabyte (GB)
•1024 GB = 1 Terabyte (TB)
•When a computer processes information, it temporarily stores instructions and data in its memory.
This internal storage, called memory, holds data that the CPU needs to access quickly. Programs
stored on external storage devices must be loaded into memory before they can run. There are two
types of memory: volatile and non-volatile. Volatile memory loses its data when the computer is
turned off, so it needs a continuous power supply to retain its contents.

7. Types of Memory:
•Random Access Memory (RAM) is a volatile memory used for temporarily holding data that the computer
is actively working on. It allows for fast reading and writing of data, which helps speed up the computer's
performance. More RAM generally means better performance, especially when paired with a good CPU.
•Read-Only Memory (ROM), on the other hand, is non-volatile and keeps its data even when the computer
is turned off. It stores essential programs needed to start the computer, like the boot-up instructions. Unlike
RAM, the data in ROM is permanent and not meant to be changed.
•Cache(pronounced "cash") is a small, fast memory that stores frequently used data and instructions to
speed up computer processes. When the processor needs information, it first checks the cache to access
it more quickly.

8. Types of Input:
Inputis any information or instructions you give to a computer. Once this input is in the computer's memory,
the CPU can use it to produce output. The four types of input are: data (like numbers or text), programs
(software), commands(instructions to perform tasks), and user responses (answers or choices you make).
•Data: Unorganized facts like words, numbers, pictures, sounds, and videos. Computers process data into
useful information.
•Program: A set of instructions that tells a computer how to process data into information. Programs are
stored on media like hard disks or CDs and respond to user commands.
•Command: An instruction given to a computer program, typically entered via keyboard shortcuts or menu
selections. Commands can be typed, selected from menus, or issued through graphical user interfaces
(GUIs).
•User Response: Instructions provided by the user in response to prompts from a program, guiding the
program’s actions, such as saving changes to a file.

9. Input devices:
An Input Device is any hardware component that allows you to enter data, programs, commands, and
user responses into a computer. Some of the commonly used input devices are listed below.
•Keyboard
•Pointing devices ( • Mouse • Joystick • Touchpad • Light Pen )
•Scanners
•Voice input systems
•Web Cam
•Bar code readers
•Microphones
•Sensors

10. Types of Output:
Output: Processed data transformed into useful information. Computers produce various outputs depending
on the hardware, software, and user needs. Common types of output include:
•TextCharacters that form words, sentences, and paragraphs. Text includes letters, numbers, punctuation
, and symbols.
•GraphicsVisual representations such as drawings, charts, and photos. Graphics can be static or
animated.
•Audio: Sound such as music or speech. Computers convert analog sound to digital format and back to
analog for playback.
•Video: Moving images captured and displayed at high speeds to appear as motion. Video is often
recorded digitally but may require conversion to analog for some devices.

11. Output devices:
An output device is any computer component capable of conveying information to a user. Some
commonly used output devices are:
•Display devices (LCDmonitors (Liquid Crystal Display) / Flat-panel displays ,LED(Light Emitting
Displays) Monitors )
•Printers include (Ink Jet printers , Laser printer)
•Audio Devices (Speakers ,Headphones)

12. Input and Output devices:
Some hardware can serve as both input and output devices. For example, a touch screen displays informati
on and detects touch inputs. When you touch the screen, its sensors register the location and trigger actions
or display different information . Thus, a touch screen functions as both an input and output device.

13. Storage devices:
Storage Devicesare media and devices used to keep and retrieve data, instructions, and information.
Memory vs. Storage
•Memory: Holds data temporarily while it is being processed by the CPU. Think of it as the top of your
desk where you work with files.
•Storage: Keeps data long-term for future use. It’s like a filing cabinet where you store files when not in
use.
Storage devices act as both input (reading data into memory) and output (writing data from memory to storage
). They are slower than memory, with access times measured in milliseconds.

14. Types of Storage devices:
•Hard Disk Drive (HDD): Uses spinning disks and read/write heads to store large amounts of data.
Common for internal storage in computers.
•Solid State Drive (SSD): Uses flash memory for faster data access and no moving parts. Replace
s HDDs in many modern computers.
•USB Flash Drive: Portable storage device using flash memory. Easy to connect via USB ports.
•Optical Discs (CDs/DVDs/Blu-ray): Use laser technology to read and write data. Used for media
distribution and backups.
•External Hard Drive: Similar to internal HDDs/SSDs but connects externally via USB or other
interfaces for additional or portable storage.
These devices are used to store and retrieve data for various applications.

15. System Unit
•The System Unit: This is the main box of a computer that houses critical electronic components, including
the CPU, memory, hard disk drive, and more. It is sometimes mistakenly called the CPU, but it also
contains the motherboard, floppy disk drive, power supply, and CD-ROM drive. The system unit is also
known as the housing or case.

16. Factors affecting computer performance :
To increase the performance there are number of factors including:
•Performance of the Microprocessor
•Performance of the Hardware devices
•Performance of the Storage devices
•Performance of the Software

17. Thank you
Any Question?