Operating System · End Term · Jan 2026 · AN

Consider the below plots representing the order in which the requests are serviced by different disk scheduling algorithms.

Match the above plots with the corresponding disk scheduling algorithm.

Consider the following program. Assume execlp succeeds.

Which output order is guaranteed?

Consider the following resource-allocation situation. • Process P1 holds resource R1 and waits for R2. • Process P2 holds resource R2 and waits for R3. • Process P3 holds resource R3 and waits for R1. • None of the processes releases its currently held resource until it acquires the requested one. Which deadlock condition is most directly exhibited by the waiting pattern above?

If the memory map for a device starts at address 0x40001000 and has a size of 8192 bytes, what is the last valid address in the memory map?

Consider that the following commands are executed in a shell with root (/) as the current directory.

What is the absolute path of the file report.txt?

In xv6 on RISC-V, which register contains the system call number when the user process traps into the kernel?

When a shell executes a command and then waits for it to finish before printing the next prompt, which sequence of system calls is most likely used?

In a 64-bit RISC-V system, the scause register stores trap information. What will be the value of scause for an Environment call from U-mode?

What is the major disadvantage of the First-Come, First-Served (FCFS) CPU scheduling algorithm?

When a process successfully invokes the exec system call, which of the following definitely remains unchanged?

Consider the code segment (for xv6) given below.

What are the base address and the end address of the count reg?

Consider the following code snippet

Which of the following statements is correct?

Consider the following processes in an xv6-like operating system: • Process P1 is waiting in the ready queue. • Process P2 is currently executing on the CPU. • Process P3 is blocked waiting for disk I/O. • Process P4 has terminated, but its parent has not yet called wait().

Assume that context switches can occur at any time during execution. The variable counter is shared between two concurrent threads/processes. Initial value: counter = 100 Program A R1 = counter R1 = R1 + 30 counter = R1 Program B R2 = counter R2 = R2 - 20 counter = R2 Which of the following can be the possible final values of counter?

Choose all correct statements regarding compiling and linking multiple C source files using gcc.

A system has 256 MiB of physical memory and uses a page size of 4 KiB. How many page frames are present in RAM? Assume 1 MiB = 2\(^{20}\) bytes and 1 KiB = 2\(^{10}\) bytes.

Consider the following processes, all arriving at time 0 and entering the ready queue in the order shown below.

If the CPU scheduling policy is Round Robin with time quantum 2, what is the average response time?

Consider the following processes scheduled using FCFS.

What is the average waiting time?

Consider the following processes scheduled using non-preemptive SJF.

What is the average response time?

A system uses a 32-bit virtual address space with a page size of 4 KiB and a single-level page table. How many entries are required in the page table? Assume 1 KiB = 2\(^{10}\) bytes