The document provides information about operating systems and Windows. It discusses the functions of an operating system including managing resources, establishing a user interface, and executing applications. It describes types of operating systems such as single-user and multi-user, and provides examples of commands used in disk operating systems and shortcuts used in Windows. It also gives an overview of Windows, listing versions and describing the directory structure and file naming functionality.

1. OPERATING SYSTEM
BY : SATYAJIT MENON
CLASS:11 C
ROLL NO. :18

2. ABOUT OPERATING SYSTEM
• An operating system (OS) is system software that
manages computer hardware and software resources
and provides common services for computer programs.
The operating system is a component of the system
software in a computer system. Application
programs usually require an operating system to
function.
• Time-sharing operating systems schedule tasks for
efficient use of the system and may also include
accounting software for cost allocation of processor
time, mass storage, printing, and other resources.

3. ABOUT OPERATING SYSTEM
• For hardware functions such as input and output
and memory allocation, the operating system acts as an
intermediary between programs and the computer
hardware, although the application code is usually
executed directly by the hardware and frequently
makes system calls to an OS function or is interrupted by it.
Operating systems are found on many devices that contain
a computer – from cellular phones consoles to web
servers and supercomputers.
• Examples of popular desktop operating systems
include Apple OS X, Linux and its variants, and Microsoft
Windows. So-called mobile operating
systems include Android and iOS. Other classes of operating
systems, such as real-time (RTOS), also exist.

5. FUNTIONS
OF
OS
An operating system has
three main functions:
(1) Manage the
computer's resources,
such as the central
processing unit, memory,
disk drives, and printers,
(2) Establish a user
interface, and
(3) Execute and provide
services for applications
software.

6. FUNTIONS OF OS IN SHORT
• Memory Management
• Processor Management
• Device Management
• File Management
• Security
• Control over system performance
• Job accounting
• Error detecting aids
• Coordination between other software and user

7. TYPES OF OS
• Single- and multi-tasking
A single-tasking system can only run one program
at a time, while a multi-tasking operating system
allows more than one program to be running in
concurrency. This is achieved by time-sharing,
dividing the available processor time between
multiple processes that are each interrupted
repeatedly in time slices by a task-scheduling
subsystem of the operating system. Multi-tasking
may be characterized in preemptive and co-
operative types. In preemptive multitasking, the
operating system slices the CPU time and

8. TYPES OF OS
dedicates a slot to each of the programs. Unix-like
operating systems, e.g., Solaris, Linux, as well
as AmigaOS support preemptive multitasking.
Cooperative multitasking is achieved by relying on
each process to provide time to the other processes
in a defined manner. 16-bit versions of Microsoft
Windows used cooperative multi-tasking. 32-
bit versions of both Windows NT and Win9x, used
preemptive multi-tasking.

9. TYPES OF OS
• Single- and multi-user
Single-user operating systems have no facilities to
distinguish users, but may allow multiple programs to
run in tandem. A multi-user operating system extends
the basic concept of multi-tasking with facilities that
identify processes and resources, such as disk space,
belonging to multiple users, and the system permits
multiple users to interact with the system at the same
time. Time-sharing operating systems schedule tasks
for efficient use of the system and may also include
accounting software for cost allocation of processor
time, mass storage, printing, and other resources to
multiple users.

10. TYPES OF OS
• Distributed
• A distributed operating system manages a group
of distinct 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
form a distributed system.[

11. TYPES OF OS
• Templated
• In an OS, distributed and cloud
computing context, templating refers to
creating a single virtual machine image as a
guest operating system, then saving it as a
tool for multiple running virtual machines. The
technique is used both in virtualization and
cloud computing management, and is
common in large server warehouses

12. TYPES OF OS
• Embedded
• Embedded operating systems are designed to
be used in embedded computer systems. They
are designed to operate on small machines
like PDAs with less autonomy. They are able to
operate with a limited number of resources.
They are very compact and extremely efficient
by design. Windows CE and Minix 3 are some
examples of embedded operating systems.

13. TYPES OF OS
• Real-time
• A real-time operating system is an operating system
that guarantees to process events or data by a specific
moment in time. A real-time operating system may be
single- or multi-tasking, but when multitasking, it uses
specialized scheduling algorithms so that a
deterministic nature of behavior is achieved. An event-
driven system switches between tasks based on their
priorities or external events while time-sharing
operating systems switch tasks based on clock
interrupts.Eg

14. COMMANDS ON DISK
OPERATING SYSTEM
• 1. CLS: this command is used to clean the screen.
• 2. DIR: this command allows the user to see all files and sub-directory in the
current directory. DIR Command lists file information in five columns; (first)
column gives primary name of the file (second) column gives extension of the file
(third) column gives the file size - number of bytes used; (fourth) column gives
the last updated date; (fifth) column gives the last updated time.
• Dir/p - page by page display of file name and directory names;
• Dir/w - width-wise display;
• Dir/s - displays all sub directory and files in the sub-directory of current directory.
• 3. Copy con:this command copies whatever typed on keyboard to the file; the file
can be closed by giving the command A2 or F6 key: eg: Copy con test .....A2.

15. COMMANDS ON DISK
OPERATING SYSTEM
• 4. Date: it displays two system date and allows the user to change it if desired ; it is
displayed in the form of mm - dd - yy; eg:c:> date - enter.
• 5. Time: it displays the system type and enables the user to change it; eg: C:> Time
- enter.
• 6. md(mkdir): it creates a new directory in sub directory in the current directory; eg:
C:> md <New directory name>
• 7. rd(rmdir): this command is used to remove a directory from the disk; it can't remove
a directory which contains sub directory or files, ie, the child should be removed from
the parent; similarly this command can't remove the current directory and root directory.
Syntax: c:> RD<Dir name>.
• 8. Type: it displays the content of saved file; eg: C:> Type> file name.

16. COMMANDS ON DISK
OPERATING SYSTEM
• 9. Ren :this command changes the name of existing file or directory:
Syntax: C:> ren <old name> new name>
• 10. Delete: delete a file from current directory; Syntax: C;> del<file
name>
• 11. Ver: it displays the version of DOS currently being used in the system;
Syntax: C:> ver
• 12. Copy :it copies the given file or files from the source directory to the
largest directory; Syntax:C:> copy<source file name> <target file name>.
• 13. Prompt: allows the user to set a new DOS prompt instead of usual C:>
or A:>; eg C:> prompt pcc; Prompt$p$g - this allows you to reset default
prompt; Prompt $d (current date); Prompt $t (current time);
• 14. Attrib: this command is used for protecting the files from accidental
changes or modification. It can also be used for making a hidden file,
archive files, read only files; Syntax: Attrib +R/-R/+H/-H/+A/-A <file
name> +FR protects the file by making it read only, -R removes the read
only protection; eg: Attrib + r <file name >

17. COMMANDS ON DISK
OPERATING SYSTEM
• 15. Scandisk/ Chkdisk: this command checks the status of the disk;
it shows a graphical display, information about the user file.
• 16. Tree: this command graphically displays the path of each
directory and sub directory in given drive; Syntax: C:> tree<
• 17. More: it displays one screen of data at a time and is used with
another command when one screen is full; if you press any key on
the next screen is displayed: Syntax C:> type abc.doc| more.
• 18. Edit: the command loads the MSDOS editor, where we can edit
files, create new files, open existing files; Syntax: C:> edit < file
name>
• 19. Label: a label is a name given to a disk which refers to
collection of filers and directories on disk; Syntax: C:>label A.
• 20. Sort this command is used for sorting data and displaying the
result on the screen: Syntax:C:>dir/sort/r (reverse order)

19. WINDOWS
• Microsoft Windows (or simply Windows) is a
metafamily of graphical operating
systems developed, marketed, and sold
by Microsoft. It consists of several families of
operating systems, each of which cater to a
certain sector of the computing industry. Active
Windows families include Windows NT, Windows
Embedded and Windows Phone; these may
encompass subfamilies, e.g. Windows Embedded
Compact (Windows CE) or Windows Server.
Defunct Windows families include Windows
9x and Windows Mobile.

20. VERSIONS OF WINDOWS
• Windows 10
• Windows 8.1
• Windows 8
• Windows 7
• Windows Vista
• Windows XP
• Windows ME

21. VERSIONS OF WINDOWS
• Windows ME
• Windows 2000
• Windows 98
• Windows NT 4.0
• Windows 95
• Windows NT 3.51
• Windows NT 3.50

23. FUNCTONALITY OF WINDOWS
• In computing, a directory structure is the way
an operating system's file system and its files are
displayed to the user. Files are typically displayed in
a hierarchical tree structure.
• A filename is a string used to uniquely identify a file
stored on the file system of a computer. Before the
advent of 32-bit operating systems, file names were
typically limited to short names (6 to 14 characters in
size). Modern operating systems now typically allow
much longer filenames (more than 250 characters
per path name element).

24. FUNCTONALITY OF WINDOWS
• In Windows, the root directory is "drive:", for
example, the root directory is usually "C:". The
directory separator is usually a "", but the
operating system also internally recognizes a "/".
Physical and virtual drives are named by a drive
letter, as opposed to being combined as one.[ This
means that there is no "formal" root directory,
but rather that there are independent root
directories on each drive. However, it is possible
to combine two drives into one virtual drive
letter, by setting a hard drive into a setting of 0

25. SHORTCUTS IN WINDOWS
• CTRL+C: Copy
• CTRL+X: Cut
• CTRL+V: Paste
• CTRL+Z: Undo
• CTRL+B: Bold
• CTRL+U: Underline
• CTRL+I: Italic
• Mouse click/keyboard modifier combinations for shell objects
• SHIFT+right click: Displays a shortcut menu containing alternative commands
• SHIFT+double click: Runs the alternate default command (the second item on the
menu)
• ALT+double click: Displays properties
• SHIFT+DELETE: Deletes an item immediately without placing it in the Recycle Bin
• General keyboard-only commands

26. SHORTCUTS IN WINDOWS
• General keyboard-only commands
• F1: Starts Windows Help
• F10: Activates menu bar options
• SHIFT+F10 Opens a shortcut menu for the selected item (this is the
same as right-clicking an object
• CTRL+ESC: Opens the Start menu (use the ARROW keys to select an
item)
• CTRL+ESC or ESC: Selects the Start button (press TAB to select the
taskbar, or press SHIFT+F10 for a context menu)
• CTRL+SHIFT+ESC: Opens Windows Task Manager
• ALT+DOWN ARROW: Opens a drop-down list box
• ALT+TAB: Switch to another running program (hold down the ALT
key and then press the TAB key to view the task-switching window)