Computer System Software

Topic: Computer System Software
Class: SSS One
Definition of Software
1. Computer software or simply software is a program that enables a computer to perform a specific task, as opposed to the physical component of the system (hardware).
2. Software is a set of instructions and procedures passed to the computer to perform certain activities or tasks.
3. It can also be defined as a set of instructions that direct the activities of the computer system to undertake a specific task.
4. Computer software is that part of a computer system that consists of encoded information or computer instructions, in contrast to the physical hardware from which the system is built.

Type of Computer Software
Software is divided into two broad groups, these are:
1. System Software
2. Application software

Definition of System Software
a. System software is a collection of programs designed to operate, control and extend the capabilities of the computer.
b. These are software that controls the way the different computer components communicate with one another.
c. It can also be defined as programs that help run the computer hardware and software.

Types of System software
The major types of system software are:
i. Operating System
ii. Translators
iii. Utility programs (or tools)

Operating System
Operating (OS) is a software program that manages the hardware and software resources of the computer and provides common services for programs. The operating system is the most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs.
Examples of Operating Systems
Mac (Macintosh)
Windows
Linux
UNIX
DOS
Android
IOS, etc

Functions of the Operating System
The major functions of the operating system are:
a. Starting the computer automatically when the power is turned on.
b. Scheduling processes
c. Controlling program execution
d. Managing the main memory
e. accounting resource usage
f. managing and manipulating files
g. controlling input and output
h. Easy interaction between humans and computer
i. Loading and scheduling users’ programs along with necessary compilers.

Types of Operating System
a. Real-time operating system (RTOS): A Real-Time Operating System, commonly known as an RTOS, is a software component that rapidly switches between tasks, giving the impression that multiple programs are being executed at the same time on a single processing core. Examples: VxWorks, QNX, eCos, RTLinux
b. Single-user, single task: As the name implies, this operating system is designed to manage the computer so that one user can effectively do one thing at a time. Examples are: Palm OS, Pocket PC, MS-DOS
c. Single-user, multi-tasking: As the name implies, this operating system is designed to manage the computer so that one user can effectively do more than one thing at a time. Examples: Windows Family, Mac OS, Linux
d. Multi-user: A multi-user operating system allows many different users to take advantage of the computer's resources simultaneously. Examples are UNIX, Novell, Windows Server
e. Distributed: A distributed operating system manages a group of independent computers and makes them appear to be a single computer. Examples are Solaris, AIX, Mach/OS
f. Embedded: Embedded operating systems are designed to be used in hand-held computer systems. Examples: Symbian, Embedded Linux, BlackBerry OS, IOS, Palm OS, Windows Mobile

User interfaces
A user interface (UI) refers to the part of an operating system that allows users to interact with the computer.
1. Graphical user Interface (GUI): This interface allows users to click and drag objects with a mouse instead of entering command line. Examples of GUI-based operating systems are Mac, Windows, and Linux.
2. Text User Interfaces (TUI)/Command line also known as command screen is a user interface that requires the user to type in commands via the keyboard to pass the instruction to the computer. Examples are DOS (Disk Operating System), Unix, etc. in MS-DOS the command line prompt is “C:/>”..

Translators
Translators are programs for converting programs in other languages into machine language instruction so that the computer can execute them.
A computer language translator is a program that translates a set of code written in one programming language into a functional equivalent of the code in another programming language.
Examples of Translators
Assembler
Compiler
Interpreter.
Assembler: An assembler is a computer program for translating assembly language into machine language. Assembly language is a mnemonic representation of machine language. The computational step where an assembler is run is known as assembly time.
Compiler: A compiler is a computer program that translates text written in a computer language into another language. The original sequence is called the source code and the output is called the object code.
Interpreter: An interpreter is a computer program that directly executes instructions written in a programming language, without previously compiling them into a machine language program. An interpreter translates one statement at a time to machine code and executes it immediately before taking the next statement.

Utility Program
Utility software also known as a service program, service routine, tool, or utility routine) is a computer software designed to help analyze, configure, optimize or maintain the computer.
Examples of Utility program
1. Anti-virus: Antivirus or anti-virus software is used to prevent, detect, and remove malware, computer viruses, computer worms, Trojan horses, spyware and adware from the computer
2. Backup Utilities: Backup utility can make a copy of all information stored on a disk, and restore either the entire disk or selected files in event of disk failure or accidental deletion.
3. Data compression utilities: output a smaller file when provided with a file.
4. File managers: It provides a convenient method of performing routine data management tasks, such as deleting, renaming, cataloguing, copying, moving, merging, etc.
5. Cryptographic utilities: cryptographic utilities encrypt and decrypt streams and files.
6. Disk Cleaners: Disk cleaners can find files that are unnecessary to the computer operation, or take up a considerable amount of space. It helps the user to decide what to delete when their hard disk is full.
7. Disk partitioners: Disk partitioners can divide an individual drive into multiple logical drives.