Fundamentals Of Operating Systems Architecture And Resource Management Practice Tests

Question 1

In a multiprogramming system, if a CPU has a utilization factor $U = 1 - p^n$, where $p$ is the probability that a process is waiting for I/O and $n$ is the number of processes in memory, calculate the minimum number of processes $n$ required to achieve a CPU utilization $U \geq 0.95$ given that $p = 0.5$.

Accepted Answer

5

Answer

3

Answer

4

Answer

6

Question 2

A system uses a table in memory to pass parameters for a system call. If the table contains $k$ parameters, each of size $s$ bytes, and the memory address of the table is stored in register $R_1$, express the total memory offset $M$ for the $i$-th parameter (where $i=0$ is the first parameter) in terms of $i$, $s$, and the base address $B$ stored in $R_1$.

Accepted Answer

M = B + (i * s)

Question 3

Consider a system where a process spends a fraction $f$ of its time performing I/O. If we ignore overhead, the CPU utilization for $n$ processes is given by $U = 1 - f^n$. If $f = 0.4$, determine the CPU utilization when $n = 3$.

Accepted Answer

0.936

Answer

0.840

Answer

0.960

Answer

0.992

Question 4

In a system using a stack for parameter passing, if a system call requires $m$ parameters of size $w$ words each, the stack pointer $SP$ must be decremented by $m 	imes w$ words before the parameters are pushed to ensure memory protection.

Accepted Answer

True

Answer

False

Question 5

Which of the following scenarios correctly identify the OS service responsible for handling errors? Select all that apply.

Answer

A division by zero error during a floating point calculation

Answer

An attempt to access a memory address outside the process's allocated segment

Answer

The scheduling of a new process to the CPU

Answer

The allocation of disk blocks for a new file

Question 6

If a system call interface uses a table indexed by an integer $N$ to map to kernel functions, and each entry in the table is a pointer of size $P = 8$ bytes, calculate the memory address of the function pointer for system call $N=12$ if the table starts at address $T = 0x4000$.

Accepted Answer

0x4060

Question 7

In a file system where the File Organization Module maps a logical block $L$ to a physical block $P$ using the formula $P = S + L$, where $S$ is the starting block address, determine the physical block address if a file starts at block $S = 500$ and the user requests logical block $L = 42$.

Accepted Answer

542

Question 8

Consider a system with a per-process open-file table and a system-wide open-file table. If two different processes open the same file simultaneously, which of the following is true regarding the file offset pointer?

Accepted Answer

Each process maintains its own unique file offset pointer in its respective per-process open-file table entry.

Answer

Both processes share a single file offset pointer in the system-wide open-file table.

Answer

The file offset is stored only in the File Control Block on the disk.

Answer

The file offset is managed exclusively by the I/O control layer.

Question 9

A file is stored using contiguous allocation starting at block $100$. If each block is $4$ KB ($4096$ bytes), calculate the physical disk address for a byte located at offset $12,288$ bytes from the start of the file.

Accepted Answer

103

Question 10

In an indexed allocation scheme, if an index block can hold $N$ pointers and each block is $B$ bytes, what is the maximum file size in bytes that can be represented by a single-level index block?

Accepted Answer

$N 	imes B$

Answer

$N + B$

Answer

$B^N$

Answer

$\frac{N}{B}$

Question 11

In a linked allocation system, the time complexity to access the $n$-th block of a file is $O(n)$ because the system must traverse the linked list of pointers from the start of the file.

Accepted Answer

True

Answer

False

Question 12

A disk has a block size of $512$ bytes. A file uses contiguous allocation starting at block $200$. If the file is $10$ blocks long, what is the range of physical block addresses occupied by this file?

Accepted Answer

200 to 209

Question 13

Which of the following are inherent disadvantages of contiguous file allocation?

Answer

External fragmentation

Answer

Difficulty in growing files

Answer

High overhead for index blocks

Answer

Slow random access

Question 14

A system uses a base register to map logical addresses to physical addresses. If a process has a logical address $L = 1024$ and the base register contains $B = 5120$, calculate the resulting physical address $P$.

Accepted Answer

6144

Question 15

Consider a memory system with fixed partitioning where partitions are $100	ext{KB}$, $200	ext{KB}$, and $300	ext{KB}$. If a process of size $150	ext{KB}$ is loaded into the $200	ext{KB}$ partition, calculate the internal fragmentation.

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 16

In a system using dynamic partitioning, external fragmentation can be completely eliminated without the use of compaction.

Accepted Answer

False

Answer

True

Question 17

Which of the following conditions must be met to perform memory compaction effectively?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 18

A memory block of $1024	ext{KB}$ contains three processes of sizes $200	ext{KB}$, $300	ext{KB}$, and $400	ext{KB}$, with $124	ext{KB}$ of total external fragmentation. Calculate the total memory currently occupied by processes.

Accepted Answer

900KB

Question 19

If a process requires $x$ memory and the available free blocks are $f_1, f_2, ..., f_n$, which strategy minimizes the leftover space in the chosen block?

Accepted Answer

Option A

Answer

Option B

Answer

Option C

Answer

Option D

Question 20

A system has a total memory of $4096	ext{KB}$. If $15\%$ of memory is reserved for the OS and the remainder is divided into $8$ equal partitions for user processes, calculate the size of each user partition in KB.

Accepted Answer

435.2KB

Fundamentals Of Operating Systems Architecture And Resource Management Practice Tests

Practice Tests

Fundamentals of Operating Systems Architecture and Resource Management

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