Describe the architecture of a mobile operating system such as Android or iOS. Discuss the key features, differences from desktop operating systems, and challenges associated with mobile OS development.

Explain the concept of virtual memory and its importance in modern operating systems. Describe the working of demand paging and how page faults are handled. Provide an example to demonstrate the process.

Differentiate between processes and threads. Explain the advantages of multithreading in an operating system. Propose a threading algorithm using a producer-consumer problem and explain how synchronization is achieved using semaphores.

Consider the following page-reference string: 1, 3, 4, 2, 7, 8, 6, 2, 3,9, 6, 4, 2, 1, 3, 5, 9, 10, 4, 1, 5, 3, 4

How many page faults would occur for following replacement algorithms assuming four frames? Remember that all frames are initially empty, so your first unique pages will all cost one fault each.

i. FIFO replacement.

ii. LRU replacement.

iii. Optimal replacement.

Compare and contrast contiguous and non-contiguous memory allocation methods. Explain the First-Fit, Best-Fit, and Worst-Fit algorithms for memory allocation with examples. Which method is more efficient and why?

Describe the structure of a disk in an operating system and explain the concept of disk scheduling. Compare the FCFS, SSTF, and SCAN scheduling algorithms. Provide an example to demonstrate the working of these algorithms.

Discuss the different techniques for I/O management in an operating system. Explain how buffering, spooling, and caching improve I/O performance. Give examples to illustrate their practical applications.

Consider the following jobs.
 

a) Using the SRTF method, compute the completion times of the above jobs, average turn around time and average waiting time.

b) Using the SJF (Shortest Job First) method, compute the completion times of the above jobs, the average turn around time and the average waiting time.

c) Using the Round Robin method (with Quantum2), compute the completion times of the above jobs and the average waiting time.

List the characteristics of the following

(i) Arithmetic Pipeline

(ii)Instruction Pipeline

(iii) SIMD arraау ррсеньго

(iv) Interconnection Structures of Multiprocesses

(v) Cache Coherence

Write a program in 8086 assembly language, which converts an input of 4 ASCII digits to an equivalent hexadecimal number. For example, an input string of 4 ASCII digita, xay "4", "5", "3" "2," will be converted to the hexadecimal equivalent of number 4532, which is 11B4, Explain the algorithm of the program.

How does the 8086 microprocessor process interrupt? Explain with the help of a diagram. Write a program using 8086 assembly language to output a string: "Present Year is 2025."

What are the different types of Registers used in the 8086 microprocessor? Explain the use of each type of register of the 8086 microprocessor. Compute the physical address for the following segment register offset pairs in an 8086 microргосение:

(i)CS: IP-12FB, 567D,

(ii) DS-BX-99AE, 7551,

(iiii) SS: SP-324177FF

Explain the use of large register file in RISC processor. Also, explain the circular buffer organisation of overlapped register windows in RISC with the help of a diagram.

Explain the Wilkes Control unit with the help of a diagram. Also, explain different microinstruction formats with the help of diagrams.

Consider a machine that uses PC, IR, AC, and MAR registers to execute different instructions. All the memory accesses during instruction execution bring data to a register named XR. ALU of the machine performs the addition operation using AC and XR registers, and results are stored in the AC register. List and explain all the microoperations required to execute the following machine instruction:

AC AC + X; where X is the address of a direct operand in the Memory Assume that PC is currently pointing to this instruction. Make and state suitable assumptions, if any.

Demonstrate how the size of a machine program changes for the computation of the expression a=(xy) + (xy+z) when different instruction sets, having zero address, one address, two address and three address instructions, are used.

 Explain the functioning of Branch, Jump and Bit manipulation instructions with the help of an example/diagram of each. Also, explain the following addressing modes with the help of an example-Relative Addressing Scheme and Base register addressing scheme.

Explain the features of the following I/O Technologies:

(i) Bit-mapped Graphics Image and Frame Buffer

(ii) Refresh Rate of Video controllers

(iii) Impact printers

(iv) Voice-based Input devices

Explain the Programmed I/O and Interrupt driven I/O techniques with the help of a diagram of each. How are these two techniques different from each other? Also, explain the steps of interrupt processing.

What is the DMA technique of data transfer? Why is DMA needed? Explain the DMA breakpoints in an instruction cycle with the help of a diagram. Also, explain any one DMA configuration.