Bits , Memory and VLSI.

 Bits - 

Bits are binary digits. Bits are foundational blocks upon which data is stored and exchanged in computers.

Bits which are 0's and 1's represent a true value and false value upon which whole system of computer are build upon. Through storing and manipulating these bits, building programs, solving problems becomes easier through logic.

Logic in the computer system is built by using Logic gates. Gates are logical unit which produces binary/Boolean output based on the input. Further logic gates are combined in order to build a circuit which stores the bits.

Flip-Flops are the devices which helps in storing those bits. The output of the flip-flop circuit remains constant 0 until the pulse changes one of the input.

The fundamental property of flip flop is to store the bit and carry it forward to the next circuit. Generally the input on both the input section of this circuit is set to be 0. upon receiving pulse (input) from other circuit it changes it output. If the input on the upper section is 1 then the output is 1, if the input in the lower section in 1 then the output is 0 , keeping in mind that the other input is 0.

Understanding the flip-flop circuit helps to get its purpose threefold. First that many GATES can be used to form circuits which is essential for building logic in computer science, Second it helps us to grasp the abstracting through which the logic can be made core while the components around it changes to prevail the same results with different efficiency, Third it makes clear that flip-flops are method of storing bits in digital system.

This method of storing bits can later be magnified by combining many small circuits together. Modern digital systems are made up of 100s of 1000s of small flip-flop circuits interconnected which works by taking previous output as an input. Indeed this technology is called as VERY LARGE SCALE INTEGRATION or VLSI.

Example of VLSI -

Image courtesy - https://electronics.stackexchange.com/questions/53117/map-processor-to-circuit-diagram

MAIN MEMORY

Now that it is made clear that the data is stored in bits, lets understand main memory. For purpose of storing data a computer contains a large amount of circuits such as flip-flops for storing bits. A computer's memory is organized in manageable unit called cells. A cell has a storing capacity of 8 bits. Size of 8 bits is called as 1 byte or a byte.

These bytes are stored in many cells. Each cell has its address. Address of the cell helps to retrieve the data stored in those cells or change it according to the operation performed.

Image courtesy - https://www.cs.emory.edu/~cheung/Courses/255/Syllabus/4-intro/memory1.html

The string of bits in the cell can be combined and stored together as 1 stream (stream is called as string of bits). In order to complete the circuitry of a main memory , the cells are combined with other circuits in order to record or retrieve or remove the data and thus a complete memory is formed. In this way data stored in the memory can be easily accessed.

This prioritized approach to the data present helps the program to run faster thus making main memory different than secondary memory like hard-drive, solid state drive etc.

Why main memory is called Random Access Memory (RAM) ? 

The main memory fetches the program data into cell from the secondary memory, while fetching it performs functions of retrieving, updating and deleting the data in cell of the running program and returns it to secondary memory after the program is done running. Also the address of different operation is present at different address of the same program. To reflect this ability of randomly accessing the cell and performing operation on it derives it name as Random Access Memory. 

Also RAM has the volatility to perform manipulation of data at any time during the programming is running.

Due to the volatility , computer memory created from such technology can be termed as Dynamic Random Access Memory (DRAM).

Synchronous Dynamic Random Access Memory(SDRAM) are very similar with some additional techniques which helps in reducing the time needed to retrieve the data.

It is due to the Random Access Memory that changing the records in the program or a file is done so quickly and efficiently without errors.