NIMCET Operating System Previous Year Questions (PYQs)
Study Stuff for MCA Examinations
A system administrator is analysing the software layers of a corporate computer. Which of the following statements correctly distinguish system software from application software?
I. Device drivers are classified as application software because end-users install them to run devices.
II. Linux, macOS, and Android are operating systems and are classified as system software.
III. The OS kernel manages CPU scheduling, memory allocation, and hardware access on behalf of programs.
IV. A web browser and a word processor are examples of system software because they help users perform common tasks.
Identify the CORRECT option.
Solution
Device drivers are system software, not application software.
Statement II is correct.
Linux, macOS, and Android are operating systems, and operating systems are system software.
Statement III is correct.
The OS kernel manages CPU scheduling, memory allocation, and hardware access.
Statement IV is incorrect.
A web browser and a word processor are application software, not system software.
So, only statements II and III are correct.
Solution
Solution
✅ Given Information:
The CPU generates 32-bit virtual addresses with a 4 KB page size. The TLB holds 128 page table entries and is 4-way set associative.
✅ Step 1: Virtual Address Breakdown:
We split the 32-bit virtual address into:
- Page Offset: 12 bits (because 4 KB = 212)
- Page Number: 20 bits (32 - 12)
✅ Step 2: TLB Breakdown:
The TLB has 128 entries, and with 4-way set associativity, there are:
128 / 4 = 32 sets, so we need 5 bits for the index.
✅ Step 3: Tag Calculation:
The total number of bits for the virtual address is 32:
- Page Offset: 12 bits
- Index: 5 bits (because we have 32 sets)
- Tag: Remaining bits = 32 - 12 - 5 = 15 bits
✅ Final Answer:
The minimum size of the TLB tag is: 15 bits
Solution
Solution
TLB Tag Size Calculation
Given:
- Virtual Address = 32 bits
- Page Size = 4 KB = \(2^{12}\) → Offset = 12 bits
- VPN = 32 − 12 = 20 bits
- TLB entries = 128, 4-way set associative → 32 sets
Set index bits: \( \log_2(32) = 5 \text{ bits} \)
TLB Tag = VPN − Set Index = 20 − 5 = 15 bits
✅ Final Answer: 15 bits
Solution
Solution
Solution
A computer has $16GB$ of RAM. It typically needs to support $100$ processes, each of which require an average of $100MB$. Will this computer benefit from a Virtual Memory system? Choose the correct option and reasoning below.
Solution
Total memory required by $100$ processes is:
$100\times 100MB=10000MB$
$10000MB\approx 10GB$
Since the computer has $16GB$ RAM, total required memory is less than available RAM.
But Virtual Memory is still useful because it provides memory isolation and protection across different processes.
Each process gets its own virtual address space, which helps prevent one process from directly interfering with another process.
Which one of the following is a disadvantage of using dynamically linked library $DLL$, compared to using statically linked library?
Solution
Using a dynamically linked library usually reduces executable file size because the library code is not fully copied into the executable.
Also, RAM usage can be reduced because the same library code may be shared by multiple programs.
A program can also take advantage of updates or bug fixes in the $DLL$ without recompiling the whole program.
So, the first three options are not valid disadvantages.
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