search
Log In
Welcome to GATE CSE Doubts, where you can ask questions and receive answers from other members of the community.
Top Users Sep 2019
  1. Satbir

    567 Points

  2. Bikram

    566 Points

  3. GAITONDE

    348 Points

  4. Vimal Patel

    87 Points

  5. Shaik Masthan

    38 Points

  6. BLACK_CLOUD

    14 Points

  7. sekhar_1621

    13 Points

  8. OgbeborBeatrice

    13 Points

  9. RAMYA.F

    9 Points

  10. vkw1111

    9 Points

Recent questions tagged operating-system

0 votes
0 answers 11 views
Suppose the following jobs are to be executed in a uni-processor system. Assume the overhead of context switching is one time unit. The average process turnaround time, the normalized turnaround time for process 2, and the processor efficiency using FCFS is, 12.8, 1.625, 83.3% 11.4, 2, 83.3% 11.6, 3.75, 80.6% 18.6, 3.375, 71.4% Shouldn’t the average turn around time be $11.8$?
asked 15 hours ago in Operating System GAITONDE 567 points 11 views
0 votes
1 answer 8 views
I always face difficulties when solving this type of question so I am looking for a shortcut. I found a simple formula here, https://www.geeksforgeeks.org/gate-gate-cs-2019-question-51/. Using this formula for this problem, (4 KB/ 8 B )^2 * 2^11 I got 128 MB ... formula. I was also not able to use the formula for https://www.geeksforgeeks.org/gate-gate-cs-2004-question-49/ Please help. Thank you.
asked 3 days ago in Operating System DukeThunders 132 points 8 views
1 vote
0 answers 7 views
This question is from iisc assignment . If a computer system has one processor, then the maximum number of processes (including both user and system processes) that can be in state RUNNING at any time instant is a) 1 b) 2 c) no more than 1 user process, but any number of system processes d) any number of both user and system processes
asked 3 days ago in Operating System shivam001 9 points 7 views
0 votes
2 answers 3 views
Is raid and buffering in syllabus?
asked 4 days ago in Operating System kshitij 12 points 3 views
0 votes
0 answers 5 views
what is the correct binary semaphore UP operation?? UP() { if(S.L is not empty) { wakeup(process p)} else S.value = 1; return; } or, UP() { S.value = 1; wakeup(process p); return; } which one is correct??
asked Sep 14 in Operating System MRINMOY_HALDER 27 points 5 views
0 votes
0 answers 9 views
In segmented paging the logical address space of a program is divided into variable sized segments. Further the segments are divided into fixed size pages The page sizes of different segments are same or different?
asked Sep 13 in Operating System aditi19 29 points 9 views
0 votes
0 answers 8 views
Can we ignore the last 3 unit of idle time as we can utilize this time by giving it to another process, if available? Can anyone explain? Consider three processes, all arriving at time zero, with total execution time of 10, 20 and 30 units, respectively. Each process spends the first 20% of ... as possible. For what percentage of time does the CPU remain idle? (a) 0% (b) 10.6% (c) 30.0% (d) 89.4%
asked Sep 13 in Operating System yashu24 10 points 8 views
0 votes
1 answer 11 views
Can anyone explain me the solution of this question? Consider the processes P1, P2, P3, P4 whose arrival times are 0, 1, 2, 3 and Burst times are 5, 2, 13, 7. If the Context Switching time is 1 unit (ms), what is the average waiting time if Shortest Job Next scheduling algorithm is used? (a) 7.5 (b) 6.25 (c) 6.5 (d) None
asked Sep 12 in Operating System yashu24 10 points 11 views
0 votes
0 answers 4 views
https://gateoverflow.in/3443/gate2007-it-10 for this question: the line : if (critical _flag == FALSE) can be written as: 1:t=critical_flag; 2:cmp t,false (compare t with false , 3 :JNZ 7(if it is not true after the comparison the zero flag is ... register the value of critical_flag is stored as false) can we argue that this is how the mutual exclusion is not preserved. Is my explanation correct.
asked Sep 11 in Operating System Doraemon 63 points 4 views
0 votes
0 answers 1 view
. A computer has 32-bit virtual addresses and 4-KB pages. The program and data together fit in the lowest page (0–4095) The stack fits in the highest page. How many page table entries are needed for two-level paging, with 10 bits in each part?
asked Sep 10 in Operating System chirudeepnamini 7 points 1 view
0 votes
3 answers 21 views
In a 32-bit machine we subdivide the virtual address into 4 pieces as follows: 8-bit 4-bit 8-bit 12-bit We use a 3-level page table, such that the first 8 bits are for the first level and so on. Physical addresses are 44 bits and there are 4 protection ... how to calculate number of bits required in each page table entry of 1st,2nd level page tables..Need help in this aspect.. Thanks in advance
asked Sep 9 in Operating System chirudeepnamini 7 points 21 views
0 votes
0 answers 5 views
Consider the function given above, assume that x is shared variable initialized to 0. suppose that the foo function is called by four concurrent processes and that each process calls foo one time which of the following output is/are possible? 1234 4321 0123 2222 4444 1235 012 1124
asked Sep 8 in Operating System abhijeetjain 6 points 5 views
0 votes
0 answers 5 views
Here is my approach: Initial all block are empty - {100,500,200,450,600} When 212 request come then blocks size after allocation - {100,288,200,450,600} When 417 request come then - {100,288,200,33,600} When 112 request come then - {100,176,200,33,600 ... sufficient space so first fit fails here Thats my approach but in given solution first fits work well. Please tell the were i am doing wrong..
asked Sep 7 in Operating System sagar2405 87 points 5 views
0 votes
0 answers 5 views
If these 3 are the min. requirement from process scheduling algorithm – Min avg waiting time Min. avg Turnaround time No starvation. then can u please fill this table below by Yes(Y) or No(N) FCFS SJF SRTF RR LRTF premptive priority Min. avg WT Min. avg TAT No starvation
asked Sep 7 in Operating System MRINMOY_HALDER 27 points 5 views
0 votes
0 answers 4 views
In this question – https://gateoverflow.in/252034/segmented-paging How to figure out that only one page table is present at a time? Overhead for only one page table is consider, Why?? Please explain...
asked Sep 6 in Operating System sagar2405 87 points 4 views
0 votes
0 answers 7 views
Is it possible for 2 running processes to share the complete memory image in physical memory? And in which situation it is possible for the processes to share the memory image in physical memory?
asked Sep 5 in Operating System !KARAN 43 points 7 views
0 votes
0 answers 9 views
The address sequence generated by tracing a particular program executing in a pure demand paging system with 100 bytes per page is 0100, 0200, 0430, 0499, 0510, 0530, 0560, 0120, 0220, 0240, 0260, 0320, 0410. Suppose that the memory can store only one page and if x is the address ... (A) 0 (B) 4 (C) 7 (D) 8 Ps: how to solve this question not getting address are allocated here when page fault occur
asked Aug 31 in Operating System Ram Swaroop 75 points 9 views
0 votes
0 answers 3 views
Is all the non-preemptive scheduler are suffer from convoy effect? And if not, then what are the schedulers which suffers from convoy effect?
asked Aug 30 in Operating System sagar2405 87 points 3 views
0 votes
1 answer 32 views
A). A deadlock will occur. B) A semaphore is not a shared variable. C). Another process may then enter the critical section violating the mutual exclusion constraint. D). A signal on a semaphore is always given from outside the critical section.
asked Aug 21 in Operating System JAYKISHAN 14 points 32 views
0 votes
0 answers 10 views
Consider a file system with block size 4kb and disk size is 28 mb, to keep track of free block in the disk a bitmap is used. Then how many disk block required for bit map? (Answer given is 7)
asked Aug 10 in Operating System suparna kar 7 points 10 views
0 votes
0 answers 3 views
Can someone please explain how TLB formula is changed when other concepts like page fault and cache concepts are introduced. There is a lot of confusion and not getting clear explanations. It would be very helpful for every beginners like me. TLB #### EMAT = Ht( t + m ) + ( ... memory concept also. ( p= page fault rate , PS= pagefault service time, c= cache access time, Hc= hit rate of cache )
asked Aug 5 in Operating System shankargadri 6 points 3 views
0 votes
0 answers 4 views
Book says that segmentation supports user’s view of memory. But with segmentation there is a problem of fragmentation. To overcome that problem we divide segments into pages where any page can be stored into any frame. But at this point(in paged segmentation) how does user view of memory gets preserved as single segment may be scattered in different parts of memory.
asked Aug 2 in Operating System Vimal Patel 199 points 4 views
0 votes
1 answer 17 views
For certain page trace starting with no page in the memory a demand paged memory system operator under the lru replacement policy results in 9 and 11 page faults when the primary memory is of 6 and 4 pages respectively when the same page trace is operated under the optimal policy the number of page faults maybe A 9 and 7 B 7 and 9 C 10 and 12 D 6 and 7
asked Aug 1 in Operating System raviteia 7 points 17 views
0 votes
1 answer 21 views
Which of the following statement is false a)with the least recently used page replacement policy when the page size is halved the number of page faults can be more than the double the original number of page faults b)the working set size is a monotonically non decreasing ... is used main memory may contain some pages which do not belong to the working set of any program d) none of the above
asked Aug 1 in Operating System raviteia 7 points 21 views
0 votes
1 answer 12 views
On a system using simple segmentation, compute the physical address for each of the logical address, given the following segment table. 1 - e, 2 - b, 3 - d, 4 - c, 5 - a 1 - b, 2 - c, 3 - e, 4 - d, 5 - a 1 - c, 2 - e, 3 - d, 4 - a, 5 - b
asked Aug 1 in Operating System Hirak 1.2k points 12 views
0 votes
1 answer 10 views
Assume a page reference string with 100 length and 5 distinct page number occuring in it, what is the lower bound on the number of page fault in best case ________.
asked Aug 1 in Operating System Hirak 1.2k points 10 views
0 votes
1 answer 28 views
0 votes
0 answers 7 views
What is the Emat (effective memory access time) when we are given page fault rate? In gate do we have to consider whether memory access time is included in the Page fault service time or not ? where { p = page fault rate, PS = Page fault service time, m = memory access time } Option 1(If we do not consider ... time ) Emat = p(PS + m) + (1-p)(m) = p(PS)+ m or Option 2: Emat = p(PS) + (1-p)(m)
asked Jul 27 in Operating System nadeshseen 42 points 7 views
0 votes
1 answer 12 views
Please explain
asked Jul 27 in Operating System Nishi Agarwal 17 points 12 views
0 votes
0 answers 15 views
Let us assume a disk with the rotational speed of 15000 rpm, 512 bytes per sector, 400 sectors per track and 1000 tracks on the disk, average seek time is 4ms. We want to transmit a file of size 1 Mbyte, which is stored contiguously on the disc. (a) What is the transfer time ... rotational delay in this case? (d) What is the total time to read 1 sector? (e) What is the total time to read 1 track?
asked Jul 24 in Operating System `JEET 144 points 15 views
0 votes
6 answers 37 views
Is there preemption in multiprogramming os? Definition which I read - Multiprogramming Os - When a process go for I/O the CPU is allocated to other process after process leaves CPU for I/O. Multitasking Os - multiprogramming os + preemption = multitasking os. ... . then my doubt is how multiprogramming os switch the process without preemption? plz clear my doubt. Has I understood wrong concept?
asked Jul 23 in Operating System Shubhm 20 points 37 views
0 votes
0 answers 2 views
Consider a hard disk with 16 recording surfaces (0-15) having 16384 cylinders (0-16383) and each cylinder contains 64 sectors (0-63). Data storage capacity in each sector is 512 bytes. Data are organized cylinder-wise and the addressing format is . A file of size 42797 KB is ... is <1200, 9, 40>. What is the cylinder number of the last sector of the file, if it is stored in a contiguous manner?
asked Jul 21 in Operating System Nihal Singh 6 points 2 views
0 votes
0 answers 7 views
Which $\text{Data Structure}$ can be used to implement blocked queue during synchronization of processes. When there are $n$ process trying to access critical section but only one of them can be in the critical section and remaining all processes need to wait in the blocked queue for critical section to be free.
asked Jul 21 in Programming & DS !KARAN 43 points 7 views
0 votes
1 answer 22 views
0 votes
2 answers 37 views
Can someone tell me how many times 0 gets printed in the following code ? main() { printf(“0”); fork(); if( fork() == 0 ) { printf(“0”); if( fork() == 0 ) { printf(“0”); } } } P.S. – Ignore the syntax error i just need the answer
asked Jul 15 in Operating System Ananya2000 14 points 37 views
1 vote
2 answers 15 views
Consider a file system with block size as 4 KB and disk size as 28 MB , to keep track of free block in the disk a bit map is used. Then how many disk blocks are required for bit map ? Please explain the solution .
asked Jul 15 in Operating System user2525 1.5k points 15 views
0 votes
1 answer 14 views
Is there any correlation between bounded waiting and starvation? Process P1 Process P2 Repeat forever V(X); CS; P(X); Repeat forever P(X); CS; V(X); initial value of semaphore X=0. What about bounded waiting and progress??
asked Jul 11 in Operating System Verma Ashish 214 points 14 views
0 votes
1 answer 12 views
Consider the following process and resource requirement of each process. Type 1 Type 2 Process Used Max Used Max P1 1 2 1 3 P2 1 3 1 2 P3 2 4 1 4 Predict the state of this system, assuming that there are a total of 5 instances of resource type 1 and 4 instances of resource type 2. Can go to safe or unsafe state based on sequence Safe state Unsafe state Deadlock state
asked Jul 3 in Operating System Amarpreet Sahani 6 points 12 views
0 votes
1 answer 6 views
An operating system consists of 3 user processes and each requiring 2 resources units R. The minimum number of resources R such that no deadlocks occur are: 3 5 4 6
asked Jul 2 in Operating System himanivatyani 6 points 6 views
1 vote
2 answers 53 views
please help me in understanding below: Consider the following pseudo code fragment: Printf (“Hello”); if(fork( )) Printf(“World”); Which of the following is the output of the code fragment? Answer is varying on compilation.
asked Jul 1 in Operating System manisha11 26 points 53 views
...