In computer hardware, the storage capacity of a magnetic disk (such as a hard disk or disk pack) depends on which combination of physical recording factors?

Introduction / Context:
Magnetic disks, such as traditional hard disk drives and older disk packs, have long been used as secondary storage devices in computer systems. Their total storage capacity is not random; it depends on how data is physically recorded on the magnetic surfaces. Understanding which technical parameters control this capacity is an important part of basic computer architecture and hardware awareness, often tested in general knowledge computer questions.

Given Data / Assumptions:

• The storage device in question is a magnetic disk.
• The options mention disk pack or disk surface, tracks per inch, and bits per inch.
• We assume a standard multi-platter disk with concentric tracks and sectors.
• The question asks which listed factors determine overall storage capacity.

Concept / Approach:
The storage capacity of a magnetic disk is essentially the total number of bits that can be recorded on all recording surfaces. That depends on three main things: how many recording surfaces are available (number of platters and sides), how densely tracks are packed on each surface (tracks per inch), and how densely bits are stored along each track (bits per inch). Multiplying these together, along with the radius and geometry of the disk, yields the total capacity. Therefore, each of the factors in the options contributes to total storage capacity, so the correct choice is that all of them matter.

Step-by-Step Solution:
Step 1: Consider the number of disk surfaces. More platters and magnetic surfaces mean more area on which data can be recorded. Step 2: Consider tracks per inch. If tracks are packed more closely (higher tracks per inch), you can record more concentric circles of data on each surface. Step 3: Consider bits per inch along each track. If bits are recorded more densely along a track (more bits per inch), each track can hold more data. Step 4: Recognise that total capacity depends on all three: surfaces, tracks per inch, and bits per inch. Step 5: Select “All of the above” as the correct answer.

Verification / Alternative check:
Manufacturers often specify areal density for disks, which combines track density (tracks per inch) and linear bit density (bits per inch). Areal density multiplied by the total recording area of all surfaces gives the total capacity. If you increase only one factor and keep the others fixed, capacity rises, but in real designs, all three are considered. Historical disk technology trends show increases in both tracks per inch and bits per inch over time, along with evolving disk pack designs with more platters, which confirms that all of these factors affect total disk capacity.

Why Other Options Are Wrong (individually incomplete):
Option A (disk pack in disk surface): Refers to the number of platters or surfaces, which matters but is only one part of the picture. Option B (tracks per inch of surface): Higher track density increases capacity but does not alone determine total storage without considering surfaces and bit density. Option C (bits per inch of tracks): Higher bit density along a track adds capacity, but again it is only one of several determining factors.

Common Pitfalls:
A common error is to focus only on one parameter, such as tracks per inch, and forget that more platters or higher bit density can have an equally large impact. Another confusion arises from unclear wording like “disk pack in disk surface”, which actually hints at multiple recording surfaces. To answer correctly, think of capacity as the total number of bits stored on all surfaces, and remember that this always depends on how many surfaces you have and how densely you place tracks and bits on each one.

Final Answer:
The storage capacity of a magnetic disk depends on All of the above mentioned factors.