A computer uses a magnetic hard disk.
Describe how data is stored on a magnetic hard disk.
Mark scheme
Award up to two marks for a linked description such as:
- A read/write head moves over the surface of the disk (1) to read/write data by detecting or changing the magnetic alignment of areas of the surface (1)
- The head magnetises areas of the disk surface in different directions (1) so each area represents a binary 1 or 0 (1)
- Data is stored on concentric circles called tracks (1) which are divided into sectors (1)
Allow one mark for tracks/concentric circles on their own.
For the second mark in the first two bullets, the response must refer to the magnetic alignment/charge being detected or changed, not just that the head reads/writes data.
Do not award a mark for 'it is magnetic' or 'it stores data in binary' with no description of how the data is stored.
Do not accept descriptions of optical storage (e.g. a laser, pits and lands) or solid state storage (e.g. electric charges in chips).
Example answers and how they were marked
The read/write head moves over the magnetic surface and magnetises areas of the disk to store the 1s and 0s.
Why: Head moves over the surface (1) and magnetises areas to represent 1s and 0s (1).
The data is stored on tracks on the disk.
Why: Tracks/concentric circles (1), but no development such as tracks divided into sectors.
It is magnetic and saves the data in 1s and 0s.
Why: Near-miss: 'magnetic' alone and 'data in binary/1s and 0s' with no description of how data is stored, which the mark scheme does not award.