OPERATING SYSTEMS Multiple Choice Questions:-1. If there are multiple recycle bin for a hard disk. You can set different size for each recycle bin b. You can choose which recycle bin to use to store your deleted files c. You can make any one of them default recycle bin d. None of above. Identify false statement. Operating System Notes for GATE. Lesson 3: Thread Creation, Manipulation and Synchronization.
Softcopy of GO 2019 (last year version)Change Logs Update July 2018This is a major update with regard to formatting. Content wise GATE 2018 and a few other new questions were added. Most of the images were redrawn and most of the contents were formatted using Latex. Also, a different version was made for printing with BW theme and QR codes for all reference links. Update September 2017This is a minor update over the last one removing some non-previous year questions which happened to come by mistake and also removing the background for questions and answers for better print quality.Update July 2017GO PDF is now being made available in multiple volumes due to the large size of the PDF and for ease of printing. The first one containing Engineering Mathematics, Discrete Mathematics, and General Aptitude can be downloaded from below link.
GO classroom account is same as GO account with a new password which is automatically emailed to all GO users. You can enroll on GATE 2018 course (all courses are free) and get a notice for further PDFs or any other updates.Update on GO PDF hard copy shall be given by August second week.For new book notifications please enroll in the below courseNew Features:. GATE 1987-1990 and 2017 questions added. New color scheme. ISI/CMI questions also added. Questions in each topic are now counted. All the questions are classified to a topicUpdate October 2016This is the recommended book by me for Q/A for GATE.
Last year, exams like ISRO, IIIT-H and some PSU exams including Kerala had many previous year GATE questions ditto. Though such things happen only for aptitude section in GATE, many other questions are derivatives of previous year questions. TIFR questions are also of the same level if not a bit harder. I do not recommend any other questions.New features:. Added number of questions to each Category. Better Topic listing.
Ability to move to topic heading from any question and category head from any topic. Moved all answers to end of each topic. Topics added as bookmark in supported PDF viewersUpdate April 2016Some features:.
Tags added to each question. Questions are ordered not only by subject but also by topic. Up-votes for answers showing the amount of acceptance.
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GATE-20012. Consider a set of n tasks with known runtimes r1, r2, rn to be run on a uniprocessor machine. Which of the following processor scheduling algorithms will result in the maximum throughput?(a) Round-Robin (b) Shortest-Job-First(c) Highest-Response-Ratio-Next (d) First-Come-First-ServedAns: option (b)Explanation:Throughput means total number of tasks executed per unit time. Shortest Job First has maximum throughput because in this scheduling technique shortest jobs are executed first hence maximum number of tasks are completed.Note: Highest-Response-Ratio-Next policy favors shorter jobs, but it also limits the waiting time of longer jobs.GATE-2002. GATE-20039. A uni-processor computer system only has two processes, both of which alternate 10 ms CPU bursts with 90 ms I/O bursts. Both the processes were created at nearly the same time. The I/O of both processes can proceed in parallel. Which of the following scheduling strategies will result in the least CPU utilization (over a long period of time) for this system?(a) First come first served scheduling(b) Shortest remaining time first scheduling(c) Static priority scheduling with different priorities for the two processes(d) Round robin scheduling with a time quantum of 5 msAns: option (d)When Round Robin scheduling is usedWe are given that the time slice is 5ms.
Consider process P and Q.Say P utilizes 5ms of CPU and then Q utilizes 5ms of CPU. Hence after 15ms P starts with I/O And after 20ms Q also starts with I/O. Since I/O can be done in parallel, P finishes IO at 105th ms (15 + 90) and Q finishes its IO at 110th ms (20 + 90). Therefore we can see that CPU remains idle from 20th to 105th ms.That is when Round Robin scheduling is used,Idle time of CPU = 85msCPU Utilization = 20/105 = 19.05%When First Come First Served scheduling scheduling or Shortest Remaining Time First is usedSay P utilizes 10ms of CPU and then starts its I/O. At 11th ms Q starts processing. Q utilizes 10ms of CPU.P completes its I/O at 100ms (10 + 90)Q completes its I/O at 110ms (20 + 90)At 101th ms P again utilizes CPU.
Hence,Idle time of CPU = 80msCPU Utilization = 20/100 = 20%Since only two processes are involved and IO time is much more than CPU time, 'Static priority scheduling with different priorities' for the two processes reduces to FCFS or Shortest remaining time first.Therefore, Round robin will result in least CPU utilization.GATE-2004. 12. 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 execution time doing I/O, the next 70% of time doing computation, and the last 10% of time doing I/O again. The operating system uses a shortest remaining compute time first scheduling algorithm and schedules a new process either when the running process gets blocked on I/O or when the running process finishes its compute burst. Assume that all I/O operations can be overlapped as much as possible. For what percentage of time does the CPU remain idle?
Consider the following table of arrival time and burst time for three processes P0, P1 and P2.-Process Arrival time Burst Time-P0 0 ms 9 msP1 1 ms 4 msP2 2 ms 9 ms-The pre-emptive shortest job first scheduling algorithm is used. Scheduling is carried out only at arrival or completion of processes.
What is the average waiting time for the three processes?(a) 5.0 ms (b) 4.33 ms (c) 6.33 ms (d) 7.33 msAns: option (a)Explanation:Execution chart is shown below.