What Is The Arithmetic Logic Unit And The Main Memory Unit?

1.  The Arithmetic Logic Unit
This unit performs all mathematical and logical functions. Mathematical functions include multiplication, division, subtraction, addition and advanced mathematics such as logarithms, trigonometry and other specialized operations .A logic functions means where a number of conditions are compared to each other. Examples of logical functions are greater than, less than, equal to, not equal to, less than to.  

2.The Main Memory Unit
This memory is the internal memory of the computer. This can temporarily store programs and data during execution. Parts of main memory may contains permanently stored instructions, that tell what to do when computer is turned on .For example, check to make sure every thing is working properly and see what peripheral equipment is attached.
As the main memory unit is located inside and has direct link with other components, so access to data and instructions is very fast. Process of entering data in memory is called writing and process of retrieving data from memory is called reading.
Today, we are using semiconductor memories. These are semi conductors integrated circuits designed to function as memory chips. The two forms of semi conductor memories are:
1 ROM (read only memory)
2 RAM (random access memory)