Computer software directs computers to perform tasks and can be divided into system software and application software. System software includes operating systems, which schedule events, allocate resources, and monitor the computer. Application software helps users perform tasks like word processing, accounting, and database management. The document discusses the major types of software, how they are acquired, and the functions of the operating system, including process management, memory management, file management, device management, security management, and the user interface. It also defines different types of operating systems such as batch processing, multi-user, multitasking, real-time, multiprocessor, and embedded operating systems.

1. Computer Software (Unit 6)
Kumar Poudyal
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2. Computer Software:
 Computer hardware is useless without
software.
 Software is the set of instructions and
associated data that direct the
computer to do a task.
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3. Types of Software
 Software can be divided into two
categories:
 system software and
 application software.
 System software helps the computer to
carry out its basic operating tasks.
 Application software helps the user
carry out a variety of tasks.
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4. The major types of software
Application software
Hardware
System software
System Software
Operating Systems
Schedules computer
events
Allocates computer
resources
Monitor events
Application Software
(Packaged and Tailored Software)
Programming languages
Assembly language
FORTRAN, BASIC, PL/1
PASCAL, C
“4th generation “ languages
Users Language
translators
Assemblers, Interpreters
and Compilers
Utility programs
Routine operations (e.g.
sort, list, print)
Manage data (e.g. create
files, merge files

5. System Software
 Manages the fundamental operations of
the computer, such as loading
programs and data into memory,
executing programs, saving data to
disks, displaying information on the
monitor, and transmitting data through
a port to a peripheral device.
 System software: operating systems,
utilities, device drivers.
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6. Application software
 Developed for a specific task , such as
word processing( MS Word/ WordPerfect),
accounting (Lotus 1-2-3/ Excel), or
database management (MS-Access/
dBASE).
 We also use graphics and presentation
software.
 Types: Packaged and Tailored Software
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7. Software Acquisition
 Freeware
 Free to all
 Copyrighted
 Distributed in machine-readable format
 Shareware
 Freely distributed for a trial period
 Pay a nominal fee to register with the
author
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8. Software Acquisition
 Open-source
 Free to all
 Source code is distributed
 May be used or altered
 Popular under the LINUX OS
 Commercial software
 Used most often
 Copyrighted
 Generally costly
 May not be copied without permission of the
manufacturer 8

9. Operating System Software
 A sofware that makes the computer hardware
work
 Provides an interface for the users to
communicate with the computer
 Handles the working of application programs
with the hardware and other software
systems
 Manage the storage and retrieval of
information using storage devices
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10. Function of OS
 Process Management
 Memory Management
 File Management
 Device Management
 Security Management
 User Interface
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11. Process Management
 Process State (new, ready, waiting,
executing, blocked…)
 Process Control Block (process id,
process state, program counter, register
information, scheduling information,
memory related information, accounting
information i.e. CPU utilization &
execution time, status information
related to I/O)
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12. Process Management (Cont..)
 Process Operations (Process creation,
process termination)
 Process scheduling (FCFS, SJF, Round
Robin)
 Process Synchronisation
 Interprocess communication
 Deadlock
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13. Memory Management
 Allocating the main memory space to the
processes
 Enabling the executing of multiple processes
at a time
 Sharing the same memory space among
different processes
 Segmentation
 Paging
 Swapping
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14. File Management
 File attributes
 File operation (creating, saving,
opening, deleting, modifying, closing,
renaming)
 File systems:
 FAT (File Allocation Table)
 NTFS (New Technology File Systems)
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15. Device Management
 Manages hardware devices
 Tracks the status of all devices
 Device drivers
 API (Application Programming
Interface)
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16. Security Management
 Internal security
 External security
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17. User Interface
 Command-line interface systems display a
command prompt, then expect the user to
type the desired commands. (Eg: UNIX, MS-
DOS )
 Graphical user interfaces (GUI) display
pictures (icons), menus, and text, which the
user may point to with a mouse or other
pointing device, then click to select the
desired function. (Eg: Macintosh OS,
Windows 95/98
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18. Types of OS
 Batch Processing OS
 Multi-user OS
 Multitasking OS
 Real-time OS
 Multiprocessor OS
 Embedded OS
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19. Batch Processing OS
 Executes only one job at a time
 Processed on the FCFS basis
 Jobs couldn’t be processed as per their
priority
 Examples: BKY, CAL and Chios
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20. Multi-user OS
 Enables multiple users to use the
resources of a computer system at the
same time.
 Allows the resources of the computer
system to be utilized in an efficient
manner
 Examples: Unix, Linux, Windows 8
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21. Multitasking OS
 Allows a user to carry out multiple tasks
at the same time on a single computer
system.
 Increases the overall performance of
the computer system
 Examples: Unix, Linux, Windows 8
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22. Real-time OS
 Specially designed and developed for
handling real-time applications.
 Time is the major constraint for these
applications
 Examples: MTOS, Lynx, RTX
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23. Multiprocessor OS
 Allows the use of multiple CPUs in a
computer system for executing multipe
processes at a time
 If one CPU fails, the other CPU takes
control and executes the currently
running process
 Examples: Linux, Unix, Windows 8
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24. Embedded OS
 Used in most electronic devices
 Provide limited functionality that is
required for the corresponding
embedded computer system
 Examples: Palm OS, Windows CE
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25. Thank you!
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