Storage Capacity of a disk pack consisting of 4 plates each having 2655 tracks…

Concept

The storage capacity of a magnetic disk pack is the product of all its geometric divisions. The governing identity is:

Capacity = (number of recording surfaces) × (tracks per surface) × (sectors per track) × (bytes per sector).

Multiplying these counts gives the total number of bytes, which is then converted to KB, MB or GB using the binary factor 1 KB = 1024 bytes (1 MB = 1024 KB, 1 GB = 1024 MB).

Application

Here the disk pack is specified directly by plates, so each plate contributes the stated 2655 tracks. Substituting the given values:

1. Surfaces (plates) = 4, tracks per surface = 2655, so total tracks = 4 × 2655 = 10,620.

2. Sectors = 10,620 × 125 = 1,327,500 sectors.

3. Bytes = 1,327,500 × 512 = 679,680,000 bytes.

4. Convert: 679,680,000 ÷ 1024 ≈ 663,750 KB ≈ 648 MB ≈ 0.63 GB (about two-thirds of a gigabyte).

Rounded to the nearest listed magnitude, this is approximately 1 GB.

Cross-check

Compare the result, ~0.65 GB, against each magnitude offered: it is a few hundred MB, i.e. on the order of 10⁸–10⁹ bytes. That sits squarely at the gigabyte scale — it is roughly a thousand times larger than a megabyte and roughly a thousand times smaller than a terabyte, and far above a few hundred KB. So the gigabyte-scale value is the only consistent approximation.