Operating system

1. Operating System
Q: What is a Operating System? Explain.
Operating System:
OS is an interface between user and hardware parts. It
controls the peripheral devices such as input/output
devices. When computer is turned on, first of all OS is
loaded into the main memory. Without system software, we
cannot interact with application software.
It manages computer hardware and software sources
common services.
Q: Describe the programs that OS runs?
Three types of programs that OS runs:
a) User programs:
Programs used by the user to perform a task.
b) System programs:
It is an interface between user and computer.
c) Driver programs:
Drivers programs are used to communicate with input
and output devices.
Q: Describe the types of interface that OS provides?
OS provides Interface, which are of two types:
A) Command Line Interface(CLI)
In command line interface, several commands are
used to operate a single function.
B) Graphical User Interface (GUI)
GUI based computers, commands are given by
graphical buttons, icons and windows. It is user friendly
and easy to use.
Q: What are the basic funtions of OS?
Basic functions of OS:

2. a) User Interface
b) Process management
c) Memory management
d) File management
e) Interrupts handling
f) Networking
All the structural blocks of OS are designed separately but
all blocks are interlinked.
Q: What is a Process manager?
A) Process Manager:
It manages different processes of CPU working at a
same type. It selects how many machine cycles are
required. It also determines the priority of the processes.
It determines which process to perform first and which
process to be performed afterwards. Highest priority
process is of input devices. It manages all the processes
to and from the CPU. It also determines the memory
allocation of the operation and operands of specific
process. It allocates the CPU to a process and also
allocates the memory to the processing data. It
deallocates the memory for the next process after the
process is completed. It has a further part which is called
as traffic controller which keeps a record and status of
all the processes.
Q: What is a memory manager?
B) Memory Manager:
It keeps the track of the memory cells which have
been filled and the cells which are empty. Memory
management is the functionality of operating system
which manages the primary memory and keeps the track
of each and every cell either it is allocated or empty/free.

3. It allocates the data to the memory cells and decides how
many memory cells are required for each instruction. It
updates the status of memory cell whenever it gets free
or deallocates. Memory management refers to the
primary memory.
Q: What is a file manager?
C) File Manager:
File manager manages the storing the files in the
organized format. File manager stores the document
block by block. It organizes the pattern of all the blocks
of the document. All the data of file in the computer is in
the form of binary block. If data is stored randomly, it
will have no meaning, so due to file management blocks
are interconnected and become meaningful.
Q: On what factors the efficiency of good OS depends?
Good operating system:
1) Efficient
Time spent to execute its programs should be short.
2) Small in size
Memory occupied should be as small as possible.
3) Reliable
The task which the user gives, is performed accurately
without malfunction.
Q: What are the types of OS?
Types of OS:
A. Batch OS:
Batch is a set of similar types of jobs given to the
computer with all the input processing parameters
required for processing.
The operating system which takes inputs as a set of
instructions (jobs) altogether. No job can be started

4. until previous job is completed. Batch processing is
technique in which OS collects one program and data
together in a batch before startup processing. OS does
the following activities related to batch processing:
a) OS defines a job which has predefined sequence
of commands, programs and data as a single
unit.
b) OS keeps a number of jobs in memory and
executes them one after the other.
c) Jobs are performed in order of submission (first
come, first serve).
Q: What are the advantages of batch processing?
Advantages of batch processing:
I. Batch processing takes much of work of operator.
II. It will increase the processing performance.
III. It is time saving and efficient.
Q: What is a real time OS?
B.Real time OS:
It is that type of processing which is required where
immediate response is needed.
For example:
- Anti-missile defense system
- Airplane landing control system
- Industrial systems
- Car electrical system
- Electronic devices
Q: What is single-user-single tasking OS?
C.Single-user-single tasking OS:
A single user can use a single job at a time for
processing. This type of processing deals with a single
user at a time running single job.

5. Q: What is a multi-tasking OS?
D.Multi-tasking OS:
Multiple tasks are given to OS at a time for the
processing. It has further two types:
- Single-user-multi tasking OS
A single user can perform multiple tasks at the same
time. Example is personal user of PC.
- Multi-user-multi tasking OS
Multiple users can perform multiple tasks at the same
time. Example is Google which can be accessed by
multiple users performing multiple tasks at a time.
These types of OS are used to create networks.
Q: What is time sharing OS?
E.Time sharing OS:
Each user is given a time slice to interact with the
CPU. The size of time slice will depend on the system.
Each user is served in a sequence. Best example is
bank in which a single manager is serving multiple
lines of clients. In time sharing OS different terminals
are connected with a single processing unit and each
terminal is given a time slot in which it can perform its
processing.
F. Distributed OS
G.Embedded OS:
Embedded systems contain embedded OS which
controls the working of embedded system.
Q: What are the special features of OS?
Special features of OS:
A. Multi-tasking
It performs only one processing at a time, but it is so
fast that it seems the all the jobs are executing at the

6. same time.
B. Parallel-tasking
It contains multiple cores (or CPUs or processing
units) which handles jobs. If multiple jobs are given to
the computer then OS will distribute all the jobs to
different processing units so all the jobs will be
processed at the same time.
Q: What are the common os and describe its differences?
Common OS and their differences:
A. Network OS:
It have some certain features that make it more suitable
for networking. Network operating system does not
requires restarting the computer when a program is
installed. Network OS provides flexible and advance
networking features and capabilities.
B. Desktop OS:
It is simply used to operate computer ardware for
application softwares and utility softwares. Desktop OS
requires a restart after a program is installed. Desktop
OS has no or limited network features and capabilities.
C. Mobile OS:
OS required by a mobile phone to operate, is called
Mobile OS.
Q: What are the different types of OS?
Different types of OS:
A.Unix:
Multi-user, Multi-tasking.
CLI
B.Dos:
Single-user, single-tasking.
CLI

7. C.Mac OS
Single-user, multi-tasking.
GUI
D.MS Windows
Single-user,multi-tasking.
GUI
E.Linux:
Multi-user, multi-tasking.
GUI and CLI
F. Palm OS:
Single-user, multi-tasking.
GUI
Q: what are the utility programs that enhance the OS?
Enhancing an OS with utility softwares:
A.Dile defragmentation
B.Data compression
C.Backup software
D.Data recovery software
E.Antivirus software
F. Firewall
G.Intrusion detection (without permission access)
H.Screen savers
Etc.
Q: List down the pc operating systems?
PC OS System:
• Dos
• Windows NT (New Technology)
32-bit OS for pc in 1993
• Windows 9x
16-bit OS supports DOS.

8. • Windows 2000 Professional
• Windows XP