Memory hierarchy is a concept that is necessary for the CPU to be able to
Computer memory is classified in this figure :
register is for holding the temporary results and variables. Accessing data from
these registers is the fastest way of accessing memory.
ü Cache is used by the CPU
for memory which is being accessed over and over again. Instead of pulling it
every time from the main memory, it is put in cache for fast access. It is also
a smaller memory, however, larger than internal register.
memory or RAM (Random Access Memory): It is a type of the computer memory and is a
hardware component. It can be increased provided the operating system can
hard disk is a hardware component in a computer. Data is kept permanently in
this memory. Memory from hard disk is not directly accessed by the CPU, hence
it is slower. As compared with RAM, hard disk is cheaper per bit.
tape memory is usually used for backing up large data. When the system needs to
access a tape, it is first mounted to access the data. When the data is
accessed, it is then unmounted. The memory access time is slower in magnetic
tape and it usually takes few minutes to access a tape.