MICROPROCESSOR AND
HARDWARE NOTES
Module-5
MODULE-5-TYPES OF MEMORY
What is a memory????
*A memory is just like a human brain.
* It is used to store data and instructions.
* Computer memory is the storage space in the computer, where data is to be
processed and instructions required for processing are stored.
*The memory is divided into large number of small parts called cells.
*Each location or cell has a unique address, which varies from zero to memory size
minus one.
* For example, if the computer has 64k words, then this memory unit has 64 * 1024
= 65536 memory locations.
The address of these locations varies from 0 to 65535.
Types of memory…..
Memory is primarily of three types –
• Cache Memory
• Primary Memory/Main Memory
• Secondary Memory
,Cache Memory
*Cache memory is a very high speed semiconductor memory which can speed up
the CPU.
*It acts as a buffer between the CPU and the main memory.
*It is used to hold those parts of data and program which are most frequently used
by the CPU.
* The parts of data and programs are transferred from the disk to cache memory by
the operating system, from where the CPU can access them.
Advantages
The advantages of cache memory are as follows –
• Cache memory is faster than main memory.
• It consumes less access time as compared to main memory.
• It stores the program that can be executed within a short period of time.
• It stores data for temporary use.
Disadvantages
The disadvantages of cache memory are as follows –
• Cache memory has limited capacity.
, • It is very expensive.
Primary Memory (Main Memory)
*Primary memory holds only those data and instructions on which the computer is
currently working.
* It has a limited capacity and data is lost when power is switched off.
It is generally made up of semiconductor device.
*These memories are not as fast as registers.
*The data and instruction required to be processed resides in the main memory.
*It is divided into two subcategories RAM and ROM.
Characteristics of Main Memory
• These are semiconductor memories.
• It is known as the main memory.
• Usually volatile memory.
• Data is lost in case power is switched off.
• It is the working memory of the computer.
• Faster than secondary memories.
• A computer cannot run without the primary memory.
Secondary Memory
*This type of memory is also known as external memory or non-volatile.
HARDWARE NOTES
Module-5
MODULE-5-TYPES OF MEMORY
What is a memory????
*A memory is just like a human brain.
* It is used to store data and instructions.
* Computer memory is the storage space in the computer, where data is to be
processed and instructions required for processing are stored.
*The memory is divided into large number of small parts called cells.
*Each location or cell has a unique address, which varies from zero to memory size
minus one.
* For example, if the computer has 64k words, then this memory unit has 64 * 1024
= 65536 memory locations.
The address of these locations varies from 0 to 65535.
Types of memory…..
Memory is primarily of three types –
• Cache Memory
• Primary Memory/Main Memory
• Secondary Memory
,Cache Memory
*Cache memory is a very high speed semiconductor memory which can speed up
the CPU.
*It acts as a buffer between the CPU and the main memory.
*It is used to hold those parts of data and program which are most frequently used
by the CPU.
* The parts of data and programs are transferred from the disk to cache memory by
the operating system, from where the CPU can access them.
Advantages
The advantages of cache memory are as follows –
• Cache memory is faster than main memory.
• It consumes less access time as compared to main memory.
• It stores the program that can be executed within a short period of time.
• It stores data for temporary use.
Disadvantages
The disadvantages of cache memory are as follows –
• Cache memory has limited capacity.
, • It is very expensive.
Primary Memory (Main Memory)
*Primary memory holds only those data and instructions on which the computer is
currently working.
* It has a limited capacity and data is lost when power is switched off.
It is generally made up of semiconductor device.
*These memories are not as fast as registers.
*The data and instruction required to be processed resides in the main memory.
*It is divided into two subcategories RAM and ROM.
Characteristics of Main Memory
• These are semiconductor memories.
• It is known as the main memory.
• Usually volatile memory.
• Data is lost in case power is switched off.
• It is the working memory of the computer.
• Faster than secondary memories.
• A computer cannot run without the primary memory.
Secondary Memory
*This type of memory is also known as external memory or non-volatile.
