Calculating Disk Track and Surface Capacity

This problem involves calculating the storage capacity of a single track and a single surface of a hard disk drive based on the given specifications. We are provided with the sector size, the number of sectors per track, and the number of tracks per surface.

Given Disk Specifications

• Sector size: 512 bytes
• Sectors per track: 50
• Tracks per surface: 2000
• Number of double-sided platters: 5 (This implies 10 surfaces, but is not needed for calculating single track or surface capacity)
• Average seek time: 10 milliseconds (Not needed for capacity calculation)

Calculate Track Capacity (T)

The capacity of a track is the total size of all sectors it contains. We can calculate this by multiplying the number of sectors per track by the size of each sector.

Formula:

Substituting the given values:

The question asks for the capacity in Kilobytes (K). We know that 1 K = 1024 bytes. So, we convert the capacity from bytes to K:

So, the capacity of a track is 25 K.

Calculate Surface Capacity (S)

The capacity of a surface is the total size of all tracks it contains. We can calculate this by multiplying the number of tracks per surface by the capacity of each track.

Formula:

Substituting the given values:

Again, the question asks for the capacity in Kilobytes (K). We convert the capacity from bytes to K:

So, the capacity of a surface is 50000 K.

Summary of Capacities

Based on our calculations:

• Track Capacity (T) = 25 K
• Surface Capacity (S) = 50000 K

Therefore, (T, S) = (25 K, 50000 K).

Comparison with Options

Let's compare our calculated values with the provided options:

The calculated capacities (T, S) = (25 K, 50000 K) match Option 3.

Revision Table: Disk Capacity Calculations

Additional Information: Hard Disk Structure and Capacity

A hard disk drive stores data magnetically on rotating platters. Understanding its structure is key to calculating storage capacity.

• Platter: A circular disk, typically made of glass or ceramic, coated with magnetic material. Data is stored on both the top and bottom surfaces.
• Surface: Each side of a platter is a surface. A drive with 5 double-sided platters has \(5 \times 2 = 10\) surfaces.
• Track: Data is recorded in concentric circles on each surface, similar to grooves on a vinyl record. Each circle is called a track. All tracks at the same radial distance across all surfaces form a cylinder.
• Sector: Each track is divided into smaller units called sectors. This is the smallest addressable unit of storage on the disk. Data is read from or written to sectors.
• Cluster: Operating systems group sectors into clusters (or allocation units) for managing storage space. A cluster is the minimum amount of disk space used to hold a file.
• Total Capacity: The total storage capacity of a hard disk can be calculated as: \[ \text{Total Capacity} = \text{Number of cylinders (tracks per surface)} \times \text{Number of surfaces} \times \text{Sectors per track} \times \text{Sector size} \] In this case, Total Capacity \( = 2000 \times 10 \times 50 \times 512\) bytes \( = 512,000,000\) bytes. In K: \(\frac{512,000,000}{1024}\) K \( = 500,000\) K. In MB (1 MB = 1024 K): \(\frac{500,000}{1024}\) MB \(\approx 488.28\) MB. In GB (1 GB = 1024 MB): \(\frac{488.28}{1024}\) GB \(\approx 0.477\) GB. Note that manufacturers often use base 10 (1 KB = 1000 bytes) for capacity which would give higher numbers. Here, we used base 2 (1 K = 1024 bytes).

Seek time is the time it takes for the read/write head to move to the correct track, which is related to disk performance, not capacity.