SHORT QUES-ANS FOR OPERATING SYSTEM

[1]what ae the differences between trap and interrupt??
Answer: An interrupt is a hardware-generated change-of-flow within the system. An
interrupt handler is summoned to deal with the cause of the interrupt; control is then returned to the interrupted context and instruction.
A trap is a software-generated interrupt.
An interrupt can be used to signal the completion of an I/O to obviate the need for device
polling. A trap can be used to call operating system routines or to catch arithmetic errors.

[2] For what types of operations  is DMA useful?? in your own word please!
Answer: DMA is useful for transferring a large quantities of data  between memory and devices. It avoids the involvement of CPU in transfers and allows the transfers more quickly and at the mean time cpu can perform other tasks concurently.

[3]give the essential properties of each of the following operating systems in short:
a. Batch operating system
b. Interactive OS
c. Time sharing OS
d. Real time OS
e. Network OS
f. Distributed OS
Answer:
(A) Batch OS:
In this OS, Jobs with similar properties are needed to be batched together and run through the computer as a group by an operator or automatic job sequencer. Performance/speed  is increased by attempting to keep CPU and I/O devices busy at all times through buffering, off-line
operation, spooling, and multi programming. Batch is good for executing large jobs
that need little interaction; it can be submitted and picked up later.

(B) Interactive OS:
This system is composed of many short transactions where the results of
the next transaction may be unpredictable. Response time needs to be short (seconds)
since the user submits and waits for the result.

(C)Time sharing OS:
This systems uses CPU scheduling and multi programming to provide
economical interactive use of a system. The CPU switches rapidly from one user to
another. Instead of having a job defined by spooled card images, each program reads

its next control card from the terminal, and output is normally printed immediately
to the screen.

(D)Real time:
Often used in a dedicated application, this system reads information from
sensors and must respond within a fixed amount of time to ensure correct performance.
e. Network.
f. Distributed.This system distributes computation among several physical processors.
The processors do not share memory or a clock. Instead, each processor has its own
local memory. They communicate with each other through various communication
lines, such as a high-speed bus or telephone line.


(E)Network OS:
it is the software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions. The network operating system is designed to allow share the files andprinter access among multiple computers in a network, typically a local area network (LAN),  The most popular network operating systems are Microsoft windows server 2003 , Microsoft windows server 2008, UNIX,LINUX etc...!

(F)Distributed OS:
This system distributes computation among several physical processors.
The processors do not share memory or a clock. Instead, each processor has its own
local memory. They communicate with each other through various communication
lines, such as a high-speed bus or telephone line.