Memory Unit

TYPES OF MEMORY

a.    Primary Memory

b.   Secondary Memory

(a) PRIMARY MEMORY

This is the memory that can be directly accessed by the CPU which constantly interact with it, retrieves data stored therein, goes through instructions and execute them as per the requirement. All the information, data and application are loaded there in uniform manner. Example is RAM (Random Access Memory) which is volatile (temporary) but fast form of memory. Apart from the main large capacity RAM, there are two subs – layers of the primary memory.

(i)   Processor registers within the processor, which are one of the fastest forms of data storage contain a word of data (usually 32 or 64 bits).

(ii)     Processor cache, which is meant for enhancing the performance of the computer. It links the

fast register to slower main memory. Cache memory loads the duplicated information that is

used most actively. It is much faster than the main memory but relatively can store limited

data.

USES OF PRIMARY MEMORY

The primary storage unit is used for the following activities:

(i)     For input and output operations.

(ii)    For manipulation of text and calculation operations.

(iii)   For logical or comparison operations.

(iv)     For storage and retrieval operations.

EXAMPLES OF PRIMARY MEMORY

(i)  RAM chip provides volatile storage, but as long as it is supplied with power, it needs no special regenerator circuits to retain the stored data.

(ii)  ROM chip retains the stored data when the power supply is cut. So, unlike RAM chips, ROM chips are not volatile. ROM chip may contain micro program that causes the machine to perform certain operations such as starting the computer. ROM chip only read and it does not accept instruction from the users.

Types of ROM

(a)   Programmable Read Only Memory (PROM): It allows a chip to be programmed by the user for converting critical and lengthy operations into micro programs

(b)   Erasable Read Only Memory (EROM): It can be erased and reprogrammed. It needs to be removed and expose to ultraviolet light for some time before it can accept any new content.

(c)    Electrical Erasable and Programmable Read Only Memory (EEPROM):  It can be reprogrammed with special electrical pulses.

Assessment :

1.    Define computer memory

2.    State types of memory we have and describe them.

Student are allowed to give corrections to the assessment given by the teacher, while the teacher support s them in order to guide them.

Assignment:

Make a research online about secondary storage devices and uses