These are 4 types of memory access methods:
1. Sequential Access:-
In this method, the memory is accessed in a specific linear sequential manner, like accessing in a single Linked List. The access time depends on the location of the data.
Applications of this sequential memory access are magnetic tapes, magnetic disk and optical memories.
2. Random Access:-
In this method, any location of the memory can be accessed randomly like accessing in Array. Physical locations are independent in this access method.
Applications of this random memory access are RAM and ROM.
3. Direct Access:-
In this method, the particular location of the memory can be accessed directly like accessing in Array. This method is a combination of above two access methods. The access time depends on both the memory organization and characteristics of storage technology. The access is semi-random or direct.
Application of thus direct memory access is magnetic hard disk, read/write header.
4. Associate Access:-
In this memory, a word is accessed rather than its address. This access access method is a special type of random access method.
Application of thus direct memory access is Cache memory.