Operating System · End Term · Jan 2026 · FN

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

What is the absolute path of the file README.md?

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 R4. • Process P4 holds resource R4 and waits for R1. • None of the processes releases its held resource until it acquires the requested one. Which deadlock condition is most directly illustrated by the waiting pattern above?

If the memory map for a device starts at address 0x50002000 and has a size of 4096 bytes, what is the last valid address in the memory map?

Consider the following program. Assume execlp succeeds.

Which output order is guaranteed?

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 keyboard I/O. • Process P4 has terminated, but its parent has not yet called wait(). Select all correct statements.

Consider the following solution for the critical section problem using a shared variable turn. Initial value: turn = 1

Which of the following statements are correct?

Assume that context switches can occur at any time during execution. The variable counter is shared between two concurrent programs. Initial value: counter = 150

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 128 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 3, what is the average response time?

Consider the code segment (for xv6) given below.

What are the base address and the end address of data_reg?

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?

Consider the following code snippet.

Which of the following statements is correct?

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

Given the hexadecimal representation of the first few bytes of different files, identify the executable ELF file.

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 S-mode?

Consider the following processes scheduled using FCFS.

What is the average waiting time?

A system uses a 32-bit virtual address space with a page size of 8 KiB and a single-level page table. How many entries are required in the page table? Assume 1 KiB = 2\(^{10}\) bytes.

Consider the following processes scheduled using non-preemptive SJF.

What is the average response time?

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.