OS 2 SEMESTER EXAM: TYBCS : sppu

Chapter 1: Process Deadlocks

Chapter 2: File system management

Q. List any two file attributes.

Answer: File system attributes are:

1) Name: File name in string of characters.

2) Type: For systems that support different file types.

3) Location: Pointer to device and location of file on that device.
4) Size: Current size of file in bytes, words or blocks
5) Protection: Who can do reading, writing, executing operations.

Q. Explain sequential and direct access methods of files.

Answer: File access refers to the manners in which file records maybe accessed.

1) Sequential Access: 

- file is processed in order one record after the other.

- operation always starts at beginning of file.

- read next : reads next portion of the file and advances file pointer.

- write next: appends to end of file and advances  to newly written block.

- rewinding file: resets file pointer to the beggining.

Advantages:

- best for tape based systems.

- best for scanning all records from a file.

Disadvantage:

- more time consuming for reading, writing and searching

- insertion and deletion takes more time

 

2) Direct Access:  

- it is a random access of file to access records directly to any file block

- read n ,where n is block number and pointer is placed at that block which is to be read

- write n, operation writes data into the nth block.

advantages:

- we can access records randomly

- suitble for disk based systems.

Chapter 3: Disk scheduling

Q. List any two disk performance parameters.

Answer: Disk performance parameters are:

1.Seek Time: Time required to move disk arm to required track.

2.Rotational delay: It is a delay caused by rotational movement of the disk platter which is needed to bring the desired data in read/write head. 

3. Transfer time: It is time it takes to read or write data from disk after the head has been positioned over the track.

4. Access Time: Access Time= Seek Time + Rotational Delay + Transfer Rate

5. Disk response time: It is the average time spent by a request waiting to perform its I/O operation. It is average of all response time requests.

Chapter 4: Introduction to distributed operating systems and architecture

Q. Define distributed system.

Answer: A distributed computer system is a system that organizes the computers on a network and communicates and coordinates through message passing. It is a collection of autonomous computers that appear to user as a single computer system.

Chapter 5: Mobile operating system

 Q. What is claim edge?

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Q. What is reuqest edge?

Q. Write any two design goals of distributed systems.

Q.What is cluster computing.

Q. What is grid computing?

Q. What is size scalability in distributed system?

Q. What is kernel?