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Permalink Reply by Yasmeen(S.admin) on February 4, 2012 at 10:29pm

Most of the MCQs are from old papers and simple...  40 and total questions are 53

2-marks questions are from old papers  2011 mosly
3- marks are also most of that are from old papers mostly from last 2011 papers
5- marks questions---1st is from old papers that are dynamic Loading advantages
2nd is about file protect that what an owner can control on file.
3rd one is a new question in which a diagram is given and in which The LRU is implemented and aging is used
the question is that what the aging is doing in combination with LRU algorithm (Its a totally new a deply conceptual question

Permalink Reply by Yasmeen(S.admin) on February 4, 2012 at 10:29pm

Scan Algorithm is sometimes called the elevator algorithm, why?

What is basic logic in FIFO page replacement algorithm?

What is Mounting? Name two types of mounting. Give your answer with respect to File System?

Write three main characteristics memory management System?
The major activities of an operating in regard to memory-management are:

• Keep track of which part of memory are currently being used and by whom.
• Decide which process are loaded into memory when memory space becomes available.
• Allocate and deallocate memory space as needed.

Provide names of common file structures. none, Simple record structure, complex structure.

What do you think that why Main Memory is kept as a volatile memory and why not a permanent storage device?

Summarize the tradeoffs among simple arrays, trees, and hash tables as implementations of a page table.

Name inter-process communication tools available in UNIX/Linux?
How to implement hold and wait which can ensure that a deadlock will not occur?
One question of Memory allocation in best fit worst case and first fit memory allocation

Mostly MCQ's were before mid term. 

Permalink Reply by Yasmeen(S.admin) on February 4, 2012 at 10:30pm

marks 2:
i.busy waiting
ii.context switching
iii.Basic logic in FIFO page replacement algorithm, 
iv.formula to find size of page table,NP*PTES
v.file control block,
vi.one of the responsibility of O.S is to use computer hardware efficiently, so look algorithm for disk scheduling,
marks 3:
i.structure of 2-level page table,
ii.if a process exits but its threads are still running, will they continue?
iii.one advantage and one disadvantage(internal fragmentation) of using a large block size to store file data,
iv.three major frames of allocation scheme, fixed proporsional,priority based.
v.in round robin scheduler deadlock and starvation can happen,

However, in a more general case, deadlock can occur in RR scheduling. Consider two processes and two locks. Process A acquires lock 1 and then yields the processor to Process B. Process B then acquires lock 2 and attempts to acquire lock 1. Because lock 1 belongs to Process A, process B will then sleep. Process A awakes and attempts to acquire lock 2. Lock 2 still belongs to process B, so neither process can move forward and you have a deadlock.


vi.three types of access modes and classes of users in UNIX protection,
marks 5:
i. A file system must keep track of free blocks on disk. Name two schemes for doing this, and one advantage for each,
ii. find max. bits for page and frame where pages=16, frame=32
iii. possible criteria to decide that which process should be terminated while dead lock detection and recovery,

Permalink Reply by Yasmeen(S.admin) on February 4, 2012 at 10:31pm

Q-list down 2 major benefits of virtual memory
q- what are the possible system for the input redirection in the UNIX/LINX system 
q- what is the purpose of stud in dynamic linking ,give answer with respect to memory 
q -what is use of mounting in file system 
q -the scan algorithm is sometime called eveloater . why ?
q -how operating attacks the" no preemption "condition necessary for feedback in order to solve the pro of deadlock 
q- what is pager ? give answer with respect to virtual memory 
q- what does the following command do in the LINX/UNIX operating system 

q- how u can differentiate between external and internal fragmentation 
q -how page fault freqancy can b used as a method of thrashing 
q- 3 major frame allocation scheme 
q -consider the round robin technique .do u think that the deadlock or starvation can happen in the round robin tech scheduling 
q- explain the work of copy on write with respect to virtual memory 

Permalink Reply by Yasmeen(S.admin) on February 6, 2012 at 7:09pm

Total 53 Questions
40 x MCQs
5 x 2 Marks Questions
5 x 3 Marks Questions
3 x 5 Marks Questions

Subjective Portion is as under:-

Question No: 41 ( Marks: 2 )
Give one solution of Dinning Philosophers problem.

Question No: 42 ( Marks: 2 )
In swapping what does mean by Roll In and Roll Out?

Question No: 43 ( Marks: 2 )
How taking backup in Linux / Unix is easier than windows?

Question No: 44 ( Marks: 2 )
Number of free frames = 64, Number of processes = 3 and Process sizes: P1 = 10 pages; P2 = 40 pages; P3 = 127 pages. Calculate free frames using fixed allocation method.

Question No: 45 ( Marks: 2 )
Virtual memory is a separation of user logical memory from Physical Memory. Is it makes programming easy or difficult?

Question No: 46 ( Marks: 3 )
What do you understand by protection bit in Primary Protection Scheme under paging?

Question No: 47 ( Marks: 3 )
Is in necessary to have reference count with in a file descriptor in order to implement a soft link?

Question No: 48 ( Marks: 3 )
If a process is starved then a system is in state of Deadlock. Statement is correct or incorrect?
Question No: 49 ( Marks: 3 )
What I the difference in Deadlock Prevention and Deadlock Avoidance

Question No: 50 ( Marks: 3 )
Differentiate between a library call and a system call

Question No: 51 ( Marks: 5 )
Following hole sizes are available in a variable memory system
20k 15k 40k 60k 10k 25k
A new process of 25k is loaded into system, which hole sizes will be used by Best Fit, First Fit and Worst Fit?

Question No: 52 ( Marks: 5 )
How a page fault occurs and who is responsible to handle page faults?

Question No: 53 ( Marks: 5 )
Differentiate between Least Frequent Used Algorithm and Most Frequent Used Algorithm in context of Page Replacement Algorithms.2 marks questions:

Permalink Reply by Yasmeen(S.admin) on February 12, 2012 at 2:05am

Q1. The maximum number of pages in process address space is one million and the total address size (p +d) of process
address space is 32- bit with page size is 4096 bytes. Calculate the number of bits required for page number (p) and the
number of bits required for offset (d)?

Q2. Number of free frames

= 64
Number of processes

= 3
Process sizes

: P1 = 10 pages; P2 = 40 pages; P3 = 127 pages

Fixed allocation
64

/3 = 21 frames per process and one put in the free frames list
Q3. disadvantage of dynamic loading

Q4. Formula for calculation of average waiting time for preemptive SJF

Q5. advantages of Preemptive verses Non-Preemptive scheduling

Q6. What is mount and its type

Q7. types of Semaphore