operating system questions
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Forum Discription: General Technical Discussions, Queries, doubts etc. for GATE in CS.
URL: http://forum.onestopgate.com/forum_posts.asp?TID=125
Printed Date: 15Jul2025 at 6:16pm
Topic: operating system questions
Posted By: Vimal
Subject: operating system questions
Date Posted: 02Feb2007 at 11:51am
CS 1998
17) Calculate the total time required to read 3 sectors on 2 sided floppy disk. Assume that each track has 8 sectors and the track to track step time is 8 milliseconds. The first sector to be read is sector 3 on track10. Assume that the diskette is soft sectored and the controller has a 1-sector buffer. The diskette pins a 300-RPM and initially, the head is on track 10 .
18) For a set-associative Cache Organization ,the parameters are as follows:
t(c) = Cache access time
t(m) = Main memory access time
L = no. of sets
b = block size
k * b = set size
Calculate the hit ratio for a loop executed 100 times where the size of the loop is n * b and n = k * m is a non-zero integer and 1 < m < L.
Give the value of the hit ratio for L = 1
25 ) a) Free disk space can be kept track of using a free list or a bit map. Disk addresses require D bits. For a disk with B blocks, F of which are free, state the conditions under which the free list uses less space than the bit map.
b) Consider a disk with C cylinders, t tracks per cylinder, s sector per track and a sector length sl. A logical file L with fixed length r1 is stored contiguously on this disk starting at location (cL , TL, sL ), where cL, tL, and sL are the cylinder, track and sector numbers respectively. Derive the formula to calculate the disk address (i.e. cylinder, track and sector ) of a logical record n assuming that rl = sl
CS 1999
Q No. 19) question are too long . I can’t type this question
http://gatementor.com/gatepapers/CS1999.pdf - http://gatementor.com/gatepapers/CS1999.pdf
2.18) Raid configuration of disks are used to provide
a) Fault-tolerance b) High speed c) High data density d) None of these
CS 2001
1.22) Which of the following requires a device driver?
a) register b) Cache c) Main memory d) Disk
Q No. 8) question are too long . I can’t type this question
http://gatementor.com/gatepapers/CS2001.pdf - http://gatementor.com/gatepapers/CS2001.pdf
9 ) a CPU has 32 bit memory address and a 256 K cache memory the cache is organized as a 4-way set associative cache with cache block size of 16 bytes.
c) What is the no. and size of comparators required for tag matching?
CS 2002
1.24) In the absolute addressing mode
a) the operand is inside the instruction
b) the address of the operand is inside the instruction
c) the register containing the address of the operand is specified inside the instruction .
d) the location of the operand is implicit
18) a computer system 32-bit virtual address and 32-bit physical address. The physical memory is byte addressable, and the page size is 4 Kbytes. It is decided to use two level page table to translate from virtual address to physical address. Equal no. of bits should be used for indexing first level and second level page table, and the size of each page table entry is 4 bytes.
b) What is the no. of page table entries that can be contained in each page?
c) How many bits are available for storing protection and other information in each page table entry?
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Replies:
Posted By: Ajay
Date Posted: 02Feb2007 at 2:56pm
Hi Vimal,
Some answers are given below.
25 ) a) Free disk space can be kept track of using a free list or a bit map. Disk addresses require D bits. For a disk with B blocks,oF of which are free, state the conditions under which the free list uses less space than the bit map.
Solution:
=====
Free disk space maintance using "Bit-map" method:
-----------------------------------------------------------
Space needed to keep track of disk blocks = B bits as one bit per block(lirrespective of #of occupied or free disk blocks)
Free disk space maintance using "Free list" method:
-----------------------------------------------------------
Space needed to keep track of disk blocks = F*D bits
So, the condition at which the bit-map method allocation requires more space than free list allocation is :
"B > F*D "
Plz correct me , if it is wrong
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