OS 2 QB

UNIT – I

1. Explain the architecture of UNIX System.

2. Draw and Explain Block diagram of UNIX kernel?

3. Explain with example Building Block Primitives

4. What is a buffer? Explain the structure of Buffer Header.

5. Explain an algorithm for Buffer Allocation

6. Explain the condition when Kernel wants a particular buffer and that buffer is

currently busy.

7. Draw and explain Data Structures for File Subsystem

8. Explain the bread algorithm?

9. Explain the advantages & disadvantages of buffer cache?

UNIT – II

1. Explain the algorithm for conversion of pathname to Inode.

2. Explain the structure of Regular file.

3. What is super block? List and explain various fields of super block?

4. What is Inode? Summarize the fields from disk inode?

5. If the super block Free Inode list is empty and remembered Inode is 470. Explain

the steps to fill the superblock free Inode list.

6. Let us assume Disk block contains 1024 bytes and there are 10 direct blocks, 1

single indirect block, 1, double indirect block, 1 triple indirect block. Find the

maximum size of the file of a file9s table of content. Write your own assumptions

if any.

7. With the following assumption, find the block number and byte offset of the inode
in the block for following inode numbers: 5153, 3015.

Assumptions:

i. Block size: 1024 bytes

ii. Size of disk inode: 64 bytes

iii. Start block of inode list: 500

8. Give the fields of in-core copy of Inode.

9. Explain iget() algorithm.

10. Explain the directories with layout example?

UNIT – III

1. Explain the dup() system call with example.

2. Explain difference between Named pipe and unnamed pipe.

3. Explain the read() system call.

4. Write short note on: Change directory and Change root.

5. Explain algorithm creat() for creating a new file.

6. Draw the file system tree before and after executing following mount() system call.

Mount(</dev/dsk1=,=/usr=,0);

7. Explain the algorithm for mounting a file system?

8. Explain the read and write operations in the pipe?

9. Explain the algorithm for open system call to open a file?

10. Draw and explain the data structures for file system when following system calls

are executed:

fd1=open(</etc/passwd=, O_RDONLY);

fd2=open(</etc/passwd=, O_WRONLY);

fd3=open(<local=, O_RDONLY);

fd4=dup(fd1);
fd5=dup(fd4);

close(fd1);

close(fd3);

11. Draw and explain the file system data structures for each statement when processes

(A/B) executes following system calls:

Process A:

fd1=open("/etc/passwd",O_RDONLY);

fd2=open("local",O_RDWR);

fd3=open("/etc/passwd",O_WRONLY);

Process B:

fd1=open("/etc/passwd",O_RDONLY);

fd2=open("private",O_RDONLY);

UNIT – IV

1. Draw and explain the complete process state transition diagram.

2. Write and explain algorithm for allocating a region.

3. Explain with diagram the context of a process in detail.

4. Explain with example mapping of process virtual address into physical memory

address.

5. List and explain the fields of process table.

6. What is region? Describe algorithm for allocate region?

7. What is U area? List fields from the U area?

8. What is a region? Discuss mapping between per-process region table and page

table.

9. Explain with example mapping of process virtual address into physical memory
address.

10. Write and explain algorithm for allocating a region.

11. What is context switch? Explain the steps for Context switch.

UNIT – V

1. Explain the algorithm for exit() system call.

2. Explain different functions of clock interrupt handler

3. Explain system calls for time?

4. What is the use of fork system call? Explain the sequence of operations kernel

executes for fork?

5. What is the use of signal? Explain the types of signals?

6. Explain System Boot and the Init process.

7. Draw and explain use level and kernel level priority.

8. Explain how kernel prevent a process from monopolizing the use of CPU in Unix System

9. Explain simple process scheduling algorithm with example.

10. Explain profiling in detail.

11. Explain process scheduling with example.

UNIT – VI

1. What is demand paging? Explain data structure used for demand paging?

2. Explain the working of page stealer process.

3. What is page fault? Explain handling of validity page fault.

4. Explain in detail allocation of space on swap device.

5. Explain the functions of line discipline and clists?

6. Explain the swapping of a process between swap space and main memory?

7. Explain the data structures for demand paging?

8. Write a short note on: Streams