Ch.

Computer system
What is a Computer system?
A combination of software and hardware together is called a computer
system a computer is device hardware that can perform operations in
accordance with the set of instructions called program software
components of the computer system
since the computer follows an input process and output cycle the
components of a computer are categorized into three parts
input device
central processing unit
output devices
input devices: input devices are responsible for taking input from users
and provide to computers some most commonly used input devices are
Keyboard
Mouse
Microphone
Web webcam
Scanner
Barcode reader
Light pen
Joystick
Output devices: output devices responsible for providing and displaying
output to users some of the most commonly used output devices are
Monitor
Printer
Plotter
Speaker
CPU(central processing unit): The CPU is the Control Center of
the computer it understands the instructions and carries out operations
on the computer accordingly it is the brain of the computer and controls
the activity performed by the computer
the CPU has three components
ALU (arithmetic and logical unit)
MU(memory unit)
CU(control unit)
ALU(arithmetic and logical unit): ALU is a component that is responsible
for all the arithmetic or logical operations done on the data arithmetic
operations are the basic mathematical calculations logical operations are
basically comparison operations involving comparing data and
determining different actions to be performed processor
CU(control unit): the control unit is a component that controls the flow of
data and operations in the computer it acts as a manager and instructs
and coordinates all the components of the CPU to perform their
respective tasks
MU(Memory unit): The memory unit is a component that is responsible for
storing all the data information and instruction memory of the computer.
It is more like a predefined workspace where the temporary information is
kept to facilitate its performance when the task is performed it clears its
memory and memory space is then available for the next task to be
performed this memory is often called main memory there are two
different types of memories
primary memory: primary memory is also known as volatile memory that
is temporary as it loses its contents when the computer power is turned
off it is an internal memory that is accessed directly by the processor
RAM: random access memory is the memory that the computer uses for
storing the programs and their data while working on them we can either
read data from the RAM or write on it hence it is called the READ/Write
memory
ROM: read-only memory is used to store the data about the hardware
which does not require frequent updates for example startup programs
that load the operating system into RAM. ROM is non-volatile memory we
can only read data from the ROM and hence called read-only memory
Cache memory: memory is a very high-speed memory that is placed
between processor and RAM to speed up the operations of the CPU
generally it is used to store the copies of data frequently accessed by ram
Secondary memory: secondary memory also known as non-volatile
memory stores data and instructions permanently for future use it is
slower than primary memory but can all be accessed by a processor
directly Examples of secondary memories are
hard disk
CD/DVD
USB flash drive
Memory card
memory unit: Byte is a unit of memory used to measure amount of space
consumed by data of or instructions in a memory
memory size conventions
1 Kilobyte = 1024 bytes
1 Megabyte = 1024 KB
1 Gigabyte = 1024 MB
1 terabyte = 1024 GB
1 Petabyte = 1024 TB
1 Exabyte = 1024 PB
Data capturing: data capture refers to the process of collecting or
inputting data from different sources. To input data different input devices
can be used such as a keyboard, scanner, camera, barcode reader, etc.
Data capturing might be a complex process due to the non-uniformity
of data
data storage: data storage refers to the process of storing capture data for
future use there are many different types of storage devices available that
can be used to store data nowadays due to the rise in computer Internet
and technology large volumes of data are being produced and hence the
storage devices should be large of capacity and updated regularly to store
a large amount of data server can be deployed over cloud computing can
also BE used
data retrieval: data retrieval refers to accessing or fetching data from
storage devices as per requirement due to the large volume of data
nowadays systems must be good quality and effective programs to access
data and minimum time
Data deletion and recovery: deleting data refers to erasing data from
storage devices there can be many reasons for deleting such data
accidental deletion and illegal deletion by hackers/mischievous mongers
when data is deleted from storage media only the status (address entry) of
data is changed and that space is shown empty to the user without
deleting data. Data recovery is a process of accessing deleted or lost data
from storage devices. Deleted data can be recovered when the space of
deleted data has not been overwritten with new data
Software: software is a set of programs that instruct the hardware what to
do and how to do it making hardware functional which ever a common
objective some examples of software are Windows 10, My SQL, MS Word,
Excel, games, etc.
types of software
system software
application software
system software: system software manages a computer system. It is
software that controls and coordinates all internal activities of a
computer system such as operating system, utility software, device driver
operating system: The operating system acts as an interference between
the user and the machine. It is a set of programs that
Manages hardware resources this
Manage memory
Display result in monitored
Control all hardware components attached to a computer system
Read data through input devices
Utility software: it is software that helps you to configure optimize and
maintain a computer. Examples of utility software are disc cleaner, file
backup utility, antivirus, firewall, disk defragmenter, etc.
device driver: a device driver is software that controls a particular type of
hardware attached to the computer it acts as an interpreter between
hardware and the computer system
Application software: this software which is designed to perform specific
tasks for the end users is called application software like Microsoft Word,
Microsoft Excel ETC there are again TO broad categories of application
software
general purpose software
customize software
general purpose software: this application software developed for generic
applications to cater to a bigger audience, in general, is called general
purpose software
customized software: these are custom or tailor-made application
software that are developed to meet the requirements of a specific
organization or an individual they are designed as per the user's
requirement for example school management software, accounting
software, etc.
operating system: an operating system can be considered to be a
resource manager that manages all the resources of a computer's hard
drive including CPU, RAM, Disk, and network.
There are different types of user interference
Command base interference
Geographical user interference
Touch base interference
Voice-based interference
command interference: command base interference requires a user to
enter the command to perform different tasks like creating, opening,
editing, or deleting files
Graphical user interference: graphical user interference lets the user run
a program or give instructions to the computer in the form of icon menus
and other visual options GUI interference includes Microsoft Windows
etc.
touch-based interference: using the touch screen a user provides input to
the operating system which the OS interprets as commands like opening
an app, closing an app, dialing a number, crawling across other apps, etc.
Voice-based interference: nowadays a user can use voice-based
commands to make a computer work in the desired way such operating
system which provide voice-based control to users including iOS(Siri)
Android(Google Now or OK Google) Microsoft Windows 10 (Cortana)