Definition
Operating System
An operation system is the most important
program that runs on a computer. It is intermediary program between hardware
and software.. It is program which supervises the activities of the computer
and activates the operation of the hardware component such as CPU, main memory,
disk drive, keyboard, monitor, printer etc
Or
A program that controls the execution of
application programs, and act as an interface between the application and the
computer hardware.
Or
An operating system is an organized
collection of programs that controls overall operation of a computer. It
manages system resources, runs programs in response to commands from the user
and supervises the interaction between the system and its users. The operating
system also forms a foundation on which applications software – such Word
Processing, Spreadsheet and Accounting programs are programs are developed and
executed
The process of loading the operating system
form the secondary storage onto the RAM is known as booting.
This is also known as the name “Interface
device”.
Example for operating system: MS-DOS,
WINDOWS-98/2000/XP/2003/2007, UNIX and LINUX.
Types of Systems
To accommodate specific user requirements,
different types of operating systems exist.
Single
User Systems
These systems execute just one
program at a time.
Multiprogramming
or Multitasking Operating System
In multiprogramming operating system, more
than one program is executed at a time.
Multitasking operating system executes several
programs at one time.
Example:
Windows XP and so on.
Serial Processing operating
system
In Serial
processing operating system the processing occur sequentially. Result of one
action is known before a next action is considered. Example the earliest computer system has no OS at all.
Or
The Serial
Processing Operating Systems are those which Performs all the instructions into
a Sequence Manner or the Instructions those are given by
the user will be executed by using the FIFO Manner means First in First Out
Mainly the Punch
Cards are used
for this. In this all the Jobs are firstly Prepared and Stored on the
Card and after
that card will be entered in the System and after that all the Instructions
will be executed one by One. But the Main Problem is that a user doesn’t
interact with the System while
he is working on the System, means the user can’t be able to enter the data for
Execution.
Batch processing operating
system
In batch processing operating system the task are
performed in batches or execution of a series of program without manual
intervention. Example the earliest computer system has no OS at
all.
Or
The Batch
Processing is same as the Serial Processing
Technique. In the
Batch Processing Similar Types of jobs are Firstly
Prepared and they
are Stored on the Card.
Time
sharing operating system
In
time sharing operating systems the operating systems shares the time
between the tasks. I.e. if job A takes 6 minutes to complete and the
predefined time to the OS is 2 min it first performs the first
job A for 2 minutes, and then takes up job B (the next one) and this way shares
its time between all the jobs arriving.
Online Timesharing operating system
online time
sharing operating system has the same function of the time sharing
operating system except that the jobs are given time in the order
they come. Example: UNIX server (multiuser system)
Real
Time system [RTOS]
A real-time operating system (RTOS) is an operating system (OS) intended to serve real-time application process data as it comes in, typically
without buffering delays. Processing time
requirements are measured in tenths of seconds or shorter. The primary aim of a real time system is to provide
immediate response to events. User convenience and resource utilization are
secondary.
Priority scheduling is used to achieve real time efficiency. Real-time
operating systems are used to control machinery, scientific instruments and
industrial systems. An RTOS typically has very little user-interface
capability, and no end-user utilities, since the system will be a "sealed
box" when delivered for use. Example PICOS 18 , pSOS
On line ticket booking is an example of the
types of processes handled by this system.
A distributed operating system manages a
group of independent computers and makes them appear to be a single computer.
The development of networked computers that could be linked and communicate
with each other gave rise to distributed computing. Distributed
computations are carried out on more than one machine. When computers in a
group work in cooperation, they make a distributed system.
Embedded
system
Like computers in cars,
traffic lights, digital televisions, ATMs,
airplane controls, point of sale (POS) terminals, digital cameras, GPS navigation systems,
elevators .They
are designed to operate on small machines like PDA/Pocket
PC (Personal Digital
Assistant) with less autonomy. They are able to operate with a
limited number of resources. They are very compact and extremely efficient by
design. Examples Windows CE (Consumer
Electronics) and Minix 3
Personal Data Assistant. Same as Handheld PC
(thin Palm top). Some cellphones have PDA capabilities, which are called 'smart
phones
Functions
of operating systems
1.
Controls
the loading and running of programs.
2.
Organizes
the use of memory between programs.
3.
Organize
priorities between programs and user.
4.
Maintains
security and access rights of user.
5.
Deals
with errors and user instructions.
6.
Control
the backing store and peripherals such as disk drives and printers.
7.
Allow
the user to save files to a backing store
8.
Control
the transfer of data to peripherals.
9.
Provides
the interface between user and computer.
Role
of operating system
- Management
of the processor
- Management
of the random access memory
- Management
of the input/output
- Management
of execution of applications
- Management
of authorizations
- File
management
- Information
management
Multitasking: when computer is able to do multiple tasks at
the same time namely as we are editing a file, another file can be printed.
This capability is called multi-taking.
Multiprogramming: is the capability by which the computer can
run multiple programs is such a way that is appears to the users that all the
programs are running at the same time. Multiprogramming is a requirement in a
multi-user system where many users share the same CPU.
Multiprocessing:
for
certain application, sometimes, the speed of the CPU is not sufficient e.g.
while processing complex mathematical equations, multiprogramming with too many
program, handling defense applications etc. in such cases the speed of the
computer may be increased by adding one or more CPU to the existing CPU, with
the OS coordinating all the CPUs help process multiple instruction
simultaneously is called a multiprocessing system.
Ques1:
What are differences between MS-DOS and UNIX
operating system?
Answer: Main differences are
- MS-DOS is a single user operating
system.
- It
have command line interface.
- DOS only supports
FAT file system.
- In
DOS filenames
are not case-insensitive.
- It dose support
internet facility.
- It
comprises of four file.
·
MSDOS.SYS
·
IO.SYS
·
COMMAND.COM
·
CONFIG.SYS
MSDOS.SYS: it store important program to manage and
organize data inside the computer.
IO.SYS: it is responsible for sending &
receiving data to peripheral.
COMMAND.COM: this file check the working process is
going well or not means it check computer unit works properly or not. It is
responsible to control of peripheral device.
CONFIG.SYS: it is an ASCII text file which is responsible
to providing a space for processing application programs.
UNIX
1.
UNIX is a Multi-user,
multitasking operating System.
2.
UNIX
does have both graphical user and command line interface
3.
UNIX
from the beginning supported many file system [FAT, NTFS].
4.
In
UNIX file name is case-sensitive.
5.
It
supports internet.
6.
It
comprises of three components.
Kernel: this is the core (central part or
foundation) of the system, controlling hardware and performing I/O operations.
Shell: shell is a reference (location or situation)
to command interpreter.
Utility programs: these support a variety of tasks, such as
copying of files, editing text, performing calculations and developing software.
Ques2.
What are differences between MS-DOS and WINDOWS
operating system?
Answer
1.
MS
DOS uses command line interface. In it operations performed through command.
Whereas window is graphical user interface (GUI) it is easier to use and
handle. We can do any thing using menu &
Mouse.Window has no
of icons to perform shortcut operations example
INTERNET, RECYCLING, MY COMPUTER, and MY DOCUMENTS
2.
MS
DOS does not support multi-user, multiprogramming but windows support.
3.
MS DOS support only FAT file system. But
windows support many file system such that FAT16, FAT32 NTFS.
4.
Security
in MS DOS is very low using FAT 16 but window support FAT32 and NTFS not easy
to break.
5.
MS
DOS is not a plug & plug devices but MS WINDOWS support. If you attach any
hardware in your pc windows detect automatically and set it.
6.
MS
DOS does not support internet facility but windows support. It is also used in
networking. Example win2000/2003.
7.
MS
DOS support only EXIT mode but window SUPPORT SHUTDOWN, LOG OFF, RESTART, STAND
BY, HIBERNET mode.
8.
MS
DOS not support USB [universal serial bus]. USB makes possible to use AGP [graphic
card], DVD, external hard disk, pen drives.
9.
MS
DOS does not support web technology means internet. But window
Support.
Question: Give the example of any four
internal and external MS-DOS command with proper syntax.
Answer: In MS-DOS there are two ways command
are executed. They are
- Internal
command
- External
command
The internal commands reside in COMMAN.COM. Which loads
automatically into memory [RAM] when the system is started?
The external command resides in the disk
[any storage medium CD] in the form of executable program files. They will be
loaded into primary memory only at the time of execution. They have extension
.EXE, .BAT, .COM.
Example of internal command
CLS, DIR, Md
(mkdir),CD (changedir), Type, Ren, Rd (rmdir), Delete, Copy, Prompt, Time, Date
Example of External command
Attrib, Tree,
Edit, Format, Label, Sys
Syntax
of four internal commands
CLS: this command is used to clean the screen.
Syntax: C:\CLS
DIR: this command is used for listing files and
directories present in the
Current disk
Syntax: C:\DIR
Type: it displays the content of saved file
Syntax: C:\ Type < file name>
Copy: this command is used for copy any file to another directory
Syntax:
C:\ Type < source file name> <target file name>
REN: this command is used to change the name of any file
or directory.
Syntax: C:\ Type < source file name> <target
file name>
DEL: this command is used for erasing any file from the disk.
Syntax: C:\ Type < file name>
Syntax
of four External commands
ATTRIB:
this command is sets the various type of attribute of a file like Read
only Archive, Hidden.
Syntax: C:\ attrib [+r]
[+a] [h] < file name >
Format: this command is sets create new track and sectors
in a disk
Syntax: C:\ format [drive name]
LABLE: this command is used to change volume label.
Syntax: C:\ label [drive name]
FDISK: this command is used to make hard driver partition.
Syntax: C:\ fdisk
SYS: this command is used for copy system files to any
disk.
Syntax: C:\ sys [drive
name]
