What is random access memory, Computer Engineering

Assignment Help:

Q. What is Random Access Memory?

We will discuss RAM as an example of sequential circuit. A memory unit is a collection of storage cells or flip flops along with associated circuits needed to transfer information in and out of device. The access time and cycle time it takes are constant and independent of location therefore the name random access memory.

172_What is Random Access Memory.png

Figure: Binary Cell

RAMs are arranged (logically) as words of fixed length. Memory communicates with other devices by data input and output lines and address selection lines and control lines which specify direction of transfer.

Now let's try to understand how data is stored in memory. The internal construction of a RAM of 'm' words and 'n' bits per word comprises m ×n binary cells and connected circuits for detecting particular words. Figure below displays logic diagram and block diagram of a binary cell.

The input is fed to AND gate 'a' in complemented form. Read operation is denoted by 1 on read/write signal. Thus during read operation only 'AND' gate 'c' becomes active. If cell has been selected then output will become equivalent to state of flip flop it implies that data value stored in flip flop is read. In write operation 'a' & 'b' gates become active and they set or clear J-K flip flop relying upon input value. Please note in case input is 0 then flip flop will go to reflected in state of flip-flop. So we say that input data has been stored in flip-flop or binary cell.

Figure below is extension of this binary cell to an IC RAM circuit where a 2×4 decoder is used to select one of the four words. (For 4 words we require 2 address lines) Please note that every decoder output is connected to a 4 bit word and read/write signal is given to every binary cell. Once decoder selects word, read/write input tells operation. This is derived using an OR gate since all non-selected cells will generate a zero output. When memory select input to decoder is 0 none of words is selected and contents of cell are unchanged irrespective of read/write input.

1320_What is Random Access Memory1.png

Figure: 4 × 4  RAM


Related Discussions:- What is random access memory

Data parallel model - parallel programming model, In the data parallel mode...

In the data parallel model, many of the parallel work focus on performing operations on a data set. The data set is usually organized into a common structure, such as an array or a

Balanced trees and their operations, what is ment by avl tree n insertion n...

what is ment by avl tree n insertion n deletion ,2-3 tress insertion n deletion

Unity - variety - principles of composition, Unity / variety Unity is ...

Unity / variety Unity is created by the use of elements that look like they belong together, in other words the piece will have a feeling of internal  consistency. The most

Benefit of digital versatile disk read only memory, Q. Benefit of digital v...

Q. Benefit of digital versatile disk read only memory? The main benefit of having CAV is that individual blocks of data can be accessed at semi-random mode. So head can be move

What do you understand by electronic funds transfer, What do you understand...

What do you understand by Electronic Funds Transfer?  Electronic Funds Transfer: It's an electronic payment method that transfers the money value from one bank account to

Find out the access time of ROM using bipolar transistors, The access time ...

The access time of ROM using bipolar transistors is about ? Ans. About 1 µ sec is the access time of ROM using bipolar transistors.

What are models and meta models, Model: It is a entire explanation of s...

Model: It is a entire explanation of something (i.e. system). Meta model: It shows the model elements, syntax and semantics of the notation that permits their manipulatio

Explain about RISC architecture, Q. Explain about RISC ARCHITECTURE? Le...

Q. Explain about RISC ARCHITECTURE? Let's first list some significant considerations of RISC architecture: 1. RISC functions are kept simple unless there is a very good reas

Describe about relationships and look up fields, Relationships are imported...

Relationships are imported from the source to finish without any hindrance but once they land in the destination they can never be changed or changed and change of extensions canno

Logical representations in artificial intelligence, Logical Representations...

Logical Representations: If every human being spoke the same kind of language, there would be several less misunderstanding in the world. The problem with software engineering

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd