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[ Option C ]

Disk scheduling algorithms manage the order in which disk I/O requests are processed. Common methods are FCFS (FIFO), SSTF, SCAN, LOOK, etc. The SCAN (also called Elevator algorithm) which moves the disk arm across the disk servicing requests in one direction.
In Batch Processing, jobs are processed in the order they arrive or according to some simple sequence. A common scheduling method is FIFO (First In First Out), where the first job to arrive is the first to be processed.
Time-sharing systems use Round Robin Scheduling to give each process a fair share of CPU.
Interrupts are handled in the reverse order of occurrence, often following a LIFO (Last In First Out) scheme where the most recent interrupt is serviced first.

[ Option A ]

Disk scheduling algorithms decide the order in which I/O requests are serviced to minimize disk head movement. Two common algorithms are:
SSTF (Shortest Seek Time First):

• Selects the request closest to the current head position.
• Reduces total head movement but can cause starvation for far-away requests.

SCAN (Elevator Algorithm):

• The disk head moves in one direction, servicing all requests until it reaches the end, then reverses direction.
• Provides more uniform wait times and avoids starvation.

[ Option D ]

RAID (Redundant Array of Independent Disks) is a storage technology that combines multiple physical disks into a single logical unit to improve performance and reliability (fault tolerance). Key characteristics of RAID include:

• Data Striping: Distributing data across multiple disks to improve read/write performance.
• Redundancy/Parity: Using extra disk space to store parity or mirrored data for fault tolerance.
• Logical View: The OS treats the RAID array as a single logical drive, even though it consists of multiple physical drives.

[ Option A ]

The rotational speed of the hard disk is 6000 RPM, which means the disk completes 6000 rotations in one minute. To find the time for one complete rotation, we divide 60 seconds by 6000, giving 60/6000=0.01 seconds per rotation.
The average rotational latency is the time the system waits for the required sector to come under the read/write head. On average, this waiting time is half of one full rotation.
So, the average latency time is 0.01/2=0.005 seconds, which can also be written as 5*10^-3 seconds.

[ Option A ]

Each sector of the disk stores 512 bytes, which means 1 KB = 2 sectors. Therefore, a file of size 42797 KB requires 42797*2 = 85594 sectors in total.
The disk has 16 recording surfaces and 64 sectors per surface, so each cylinder contains 16*64 = 1024 sectors. This means that once 1024 sectors are filled, the storage moves to the next cylinder.
The file starts at disk location <1200, 9, 40>. The starting sector number within cylinder 1200 is calculated as (9*64)+40 = 616. Hence, the number of free sectors remaining in cylinder 1200 is 1024-616 = 408 sectors.
After filling these 408 sectors, the remaining sectors to be stored are 85594-408 = 85186 sectors. These remaining sectors occupy 83 complete cylinders because 83*1024 = 84992 sectors.
Since some sectors are still left after filling these 83 cylinders, they go into the next cylinder, which is cylinder number 1284.

[ Option A ]

In an operating system, multiple processes often request disk I/O operations at the same time. To manage these requests efficiently, the OS uses Disk Scheduling Algorithms, which decide the order in which the disk head (arm) moves to service requests. The main goal is to reduce Seek Time, which is the time taken by the disk arm to move to the track where data is located.

Among the given options, the Shortest-Service-Time-First (SSTF) algorithm selects the disk I/O request that is closest to the current position of the disk arm. This means the arm moves the least possible distance, which minimizes seek time and improves performance.

[ Option C ]

• FAT32 generally has lower disk utilization compared to NTFS because it uses larger cluster sizes, which leads to more unused space.
• NTFS supports advanced features like better caching, journaling, and efficient space management, which usually makes its read and write performance better than FAT32, especially on large disks.
• FAT32 does not support individual files up to 32 GB. The maximum file size supported by FAT32 is only 4 GB.
• NTFS stands for New Technology File System.

[ Option C ]

RAID (Redundant Array of Independent Disks) is a storage technology that combines multiple physical disks into one logical unit for better performance, reliability, or both. Each RAID level has a specific method for distributing and storing data and parity across disks.