Difference between ROM and PROM

ROM

1)Non-programmable.

2)Not flexible(because data can't be changed.

3)It is comparatively slower.

4)Economical only when produced in large volumes.

5)Used in PC's.

6)Writing of cell contains mainly done by 'masking; mechanisms.

PROM

1)Programmable.

2)Flexible(Field-Programmable i.e. can be programmed in any place of work).

3)It is comparatively faster.

4)Economical even when produced in small volume.

5)Mainly used for reserarche and development purpose.

6) Mainly done electrically.