Key features of the Operating System
User interfaceisone of the
significant feature in Operating System. The only way that user can make
interaction with a computer. If the computer interface is not user-friendly,
the user slowly reduces the computer usage from their normal life. This is the
main reason for the key success of GUI (Graphical User Interface) based
Operating System. The GUI is a window based system with a pointing device to
direct I/O, choose from menus, make selections and a keyboard to enter text.Its
vibrant colours attract the user very easily. Beginners are impressed by the
help and pop up window message boxes. Icons are playing vital role of the
Now Linux distribution is also
available as GUI based Operating System. The following points are considered
when User Interface is designed for an application.
· The user interface should enable
the user to retain this expertise for a longer time.
· The user interface should also
satisfy the customer based on their needs.
user interface should save user’s precious time. Create graphical elements like
Menus,Window,Tabs, Icons and reduce typing work will be an added advantage of the
ultimate aim of any product is to satisfy the customer. The User Interface is
also to satisfy the customer.
user interface should reduce number of errors committed by the user with a
little practice the user should be in a position to avoid errors (Error Log
Memory Management is the process
of controlling and coordinating computer’s main memory and assigning memory
block (space) to various running programs to optimize overall computer
performance. The Memory management involves the allocation of specific memory
blocks to individual programs based on user demands. At the application level,
memory management ensures the availability of adequate memory for each running
program at all times.
The objective of Memory Management
process is to improve both the utilization of the CPU and the speed of the
computer’s response to its users via main memory. For these reasons the
computers must keep several programs in main memory that associates with many
different Memory Management schemes.
The Operating System is
responsible for the following activities in connection with memory management:
track of which portion of memory are currently being used and who is using
which processes (or parts of processes) and data to move in and out of memory.
and de-allocation of memory blocks as needed by the program in main memory.
Process management is function
that includes creating and deleting processes and providing mechanisms for
processes to communicate and synchronize with each other.
A process is the unit of work
(program) in a computer. A word-processing program being run by an individual
user on a computer is a process. A system task, such as sending output to a
printer or screen, can also be called as a Process.
A computer consists of a
collection of processes, they are classified as two categories:
System processes which is executed by system code
Processes which is execute by user code
All these processes can
potentially execute concurrently on a single CPU.
A process needs certain resources
including CPU time, memory, files and I/O devices to finish its task.
The Operating System is
responsible for the following activities associated with the process
processes and threads on the CPUs
and deleting both user and system processes
and resuming processes
mechanisms for process synchronization
mechanisms for process communication
The following algorithms are
mainly used to allocate the job (process) to the processor.
1. FIFO 2. SJF 3. Round Robin 4. Based on
This algorithm is based on queuing
technique. Assume that a student is standing in a queue to get grade sheet from
his/her teacher. The other student who stands first in the queue gets his/ her
grade sheet first and leaves from the queue. Followed by the next student in
the queue gets it collected and so on. This is the basic logic of the FIFO
Technically, the process that
enters the queue first is executed first by the CPU, followed by the next and
so on. The processes are executed in the order of the queue.
This algorithm works based on the
size of the job being executed by the CPU.
Consider two jobs A and B.
1) A = 6 kilo bytes 2) B = 9 kilo bytes
First the job “A” will be assigned
and then job “B” gets its turn.
The Round Robin (RR) scheduling
algorithm is designed especially for time sharing systems. Jobs (processes) are
assigned and processor time in a circular method. For example take three jobs
A, B, C. First the job A is assigned to CPU then job B and job C and then again
A, B and C and so on.
The given job (process) is
assigned based on a Priority. The job which has higher priority is more
important than other jobs. Take two jobs A and B. Let the priority of A be 5
and priority B be 7.
Job B is assigned to the processor
before job A.
The major challenge in computer
and software industry is to protect user’s legitimate data from hackers. The
Operating System provides three levels of securities to the user end. They are
In order to access the files
created by other people, you should have the access permission. Permissions can
either be granted by the creator of the file or bythe administrator of the
System level security is offered
by the password in a multi-user environment.
Both windows and Linux offer the
Network security is an indefinable
one. So people from all over the world try to provide such a security.
All the above levels of security
features are provided only by the Operating System.
The Operating Systems should be
robust. When there is a fault, the Operating System should not crash, instead
the Operating System have fault tolerance capabilities and retain the existing
state of system.
File management is an important
function of OS which handles the data storage techniques. The operating System
manages the files, folders and directory systems on a computer. Any type of
data in a computer is stored in the form of files and directories/folders
through File Allocation Table (FAT). The FAT stores general information about
files like filename, type (text or binary), size, starting address and access
mode (sequential/indexed / indexed-sequential/ direct/relative). The file
manager of the operating system helps to create, edit, copy, allocate memory to
the files and also updates the FAT. The OS also takes care of the files that
are opened with proper access rights to read or edit them. There are few other file
management techniques available like Next Generation File System (NTFS) and
This is a one of the features of
Operating System. It has two or more processors for a single running process
(job). Processing takes place in parallel is known as parallel processing. Each
processor works on different parts of the same task or on two or more different
tasks. Since the execution takes place in parallel, this feature is used for
high speed execution which increases the power of computing.
This is a one of the features of
Operating Systems. It allows execution of multiple tasks or processes
concurrently. For each task a fixed time is allocated. This division of time is
called Time- sharing. The processor switches rapidly between various processes
after a time is elapsed or the process is completed.
For example assume that there are
three processes called P1, P2, P3 and time allocated for each process 30, 40,
50 minutes respectively. If the process P1 completes within 20 minutes then
processor takes the next process P2 for the execution. If the process P2 could
not complete within 40 minutes, then the current process P2 will be paused and
switch over to the next process P3.
This feature takes care of the
data and application that are stored and processed on multiple physical
locations across the world over the digital network (internet/intranet). The
Distributed Operating System is used to access shared data and files that reside
in any machine around the world. The user can handle the data from different
locations. The users can access as if it is available on their own computer.
The advantages of distributed
Operating System are as follows:
user at one location can make use of all the resources available at another
location over the network.
computer resources can be added easily in the network
the interaction with the customers and clients.
the load on the host computer.