Cache Memory

Cache memory is a high-speed memory, which is small in size but faster than the main memory (RAM). The CPU can access it more quickly than the primary memory. So, it is used to synchronize with high-speed CPU and to improve its performance.

A cache memory works on the principle of locality of reference, a term for the phenomenon in which the same values, or related storage locations, are frequently accessed, depending on the memory access pattern. Caching improves access time and reduces data traffic to data sources that have limited throughput. 

 cache memory is much smaller than main memory. Consequently, it has less storage space. It is also more expensive than main memory, as it is a more complex chip that yields higher performance.

What it sacrifices in size and price, it makes up for in speed. Cache memory operates between 10 to 100 times faster than RAM, requiring only a few nanoseconds to respond to a CPU request.

 

Difference Between ASCII and EBCDIC

 

Difference Between ASCII and EBCDIC

Definition

ASCII is a character encoding standard for electronic communication. EBCDIC is an eight-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems.

Stands for

ASCII stands for American Standard Code for Information Interchange. EBCDIC stands for Extended Binary Coded Decimal Interchange Code.

Number of bits Represent a Character

Further, ASCII uses 7 bits to represent a character. EBCDIC uses 8 bits to represent a character.

Number of Characters

Also, ASCII represents 128 (2⁷) characters while EBCDIC represents 256 (2⁸) characters.

Efficiency

Moreover, the same character in ASCII requires 7 bits, but EBCDIC required 8 bits. Therefore, ASCII is more efficient than EBCDIC.

Character Order

Besides, ASCII arranges the characters in consecutive order. EBCDIC groups 9 characters at a time.

Compatibility

Additionally, ASCII is compatible with modern encodings such as Unicode. It is possible to open ASCII files with Unicode. On the other hand, EBCDIC is not compatible with modern encodings such as Unicode.

Conclusion

ASCII and EBCDIC are two character encoding standards. The main difference between ASCII and EBCDIC is that the ASCII uses seven bits to represent a character while the EBCDIC uses eight bits to represent a character.

ASCII & EBCDIC

ASCII  

ASCII stands for American Standard Code for Information Interchange. It is an encoding standard that represents digits, letters, and symbols using numbers. The digits can be 1, 2, 3, etc. while the letters are a, b, c, A, B, C, etc. The symbols are characters like !, $, and #. Therefore, it is possible to convert any piece of text to the corresponding set of numbers using ASCII. This conversion makes it easier to store them in the computer memory. 

ASCII (American Standard Code for Information Interchange) is the most common character encoding format for text data in computers and on the internet. In standard ASCII-encoded data, there are unique values for 128 alphabetic, numeric or special additional characters and control codes.

ASCII encoding is based on character encoding used for telegraph data. The American National Standards Institute first published it as a standard for computing in 1963.

 

EBCDIC

EBCDIC stands for Extended Binary Coded Decimal Interchange Code. It is mainly used on IBM mainframe and IBM midrange computer operating systems. It is also supported by some platforms other than IBM. EBCDIC uses 8 bits to represent a single character, and it represents a 256 (2⁸) alphanumeric and special characters. There are several disadvantages to EBCDIC. When compared to ASCII, the same character which takes 7 bits to represent in ASCII will take 8 bits in EBCDIC. Therefore, EBCDIC is less efficient than ASCII.

Data Warehouse and Data Lake

 Data Warehouse and Data Lake in a nutshell

A Data Warehouse is used as a central storage for large amounts of structured data that might be coming from various sources. 

Such stores are very important to companies as they can be used to deliver insights from across the organisation to support decision making.

On the other hand, a Data Lake is a flexible storage that is used to store unstructured, semi-structured or structured raw data. The stored data is unprocessed and the structure is usually applied when it is retrieved. Note however that a Data Lake is not a replacement for a Data Warehouse.

Which to choose

Data Warehouses and Lakes are both used by organisations as centralised data stores that enable different users and organisation units to access and use data to extract insights and perform any sort of analysis. Usually an organisation will need both a Data Lake and a Warehouse to support all the required use-cases and end users.

A data lake is capable of housing all data of any form; from structured to unstructured. Additionally, it does not require any sort of pre-processing before storing the data as this can happen once it is stored in the data lake. Data Lakes are mostly useful to Data Scientists and Engineers that require access to even unstructured data that will help them build Artificial Intelligence or Machine Learning models. Data Lakes are also more cost efficient compared to Data Warehouses as they don’t require data to have any particular format such as a schema.

Now a data warehouse is only capable of storing structured data which are ready to be analysed by specific organisation units in order to unveil business insights. Therefore, ETL processes are usually required to be built around the Data Warehouse. ETL functionality enables data to be stored in the expected format and extracted or transformed so that users can perform particular tasks over them. For that reason, Data Warehouses are very powerful for business or operations analysts that require to have access to relational data with schema that will enable them to create reports and support decision making by discovering insights.

A Final Word

In this article, we discussed the key differences between Data Lakes and Warehouses. Note though that this is not an apple-to-apple comparison.Both support different use-cases and serve different users and usually organisations require both to operate efficiently.

Data Lakes are more flexible and schema-less stores that are capable of storing unstructured, semi-structured or structured data. They are usually useful to more technical users such as Data Scientists or Engineers. On the other hand, Data Warehouses can only accept relation data which in turn is more useful to less technical people who need access to ready-for-analysis data.

Hard Disk Drive

 Hard drive is a non-volatile memory hardware which store all your computer’s information and data physically in it and houses the hard disk. Sometimes hard disk is also known by the terms Hard Disk Drive.

A Hard Disk Drive has a magnetic material coated plates where the information to be recorded. In contrast to sequentially addressable storage media such as magnetic tape or punched tape drives, Hard Disk Drive is a direct access storage device or DASD, as data can be accessed directly from a Hard Disk Drive.

Structure  of Hard Disk Drive

Common form factors for Hard Disk Drive (the width) is 5.25 “, 3.5”, 2.5 “and 1.8” . Upto 0.85 inch Hard Disk Drive is available but usually 3.5 inch hard drive is the standard in desktop computers. A hard disk consists of one or more rotating mounted disks, one axis, also called spindle, an electric motor to rotate the disks, moving heads which read and writes the data, an IC for for controlling the motor and head, a dedicated RAM, outer very strong casing and the interfaces to attach for power supply and data exchange.

Function Of Hard Drive

The main function of hard disk is to store data for long term and data can be computer’s operating systems, applications, documents, personal files and so on. Now the main thing that need to notice that how much amount of data storage capacity hard drive have and that measured in gigabytes or terabytes. Performance refers to read and write speeds, latency, seek time. Seek and latency time measured in the time that are going to take magnetic heads in hard disk to access the data desired and the read write speed and data transfer rate are measured that how much capacity data can be written from the drive and read from a desired location in specific amount of time.

Network Model

 The term computer network model defines the category in which a computer network can be grouped into. Networks are divided into two broad categories:

1.Peer to peer or Workgroup Model

2.Domain based model or Client/server model

1.Peer to peer or Workgroup Model

When nodes or workstations perform the same communication functions, they are referred to as peers, in this network model, both server and client operations are performed by the same computer. Each user administers his/her workstation and the resources in it. In a peer-to-peer network, there are no dedicated servers, and there is no hierarchy among the computers. All the computers are equal and therefore are known as peers. Each computer functions as both a client and a server, and there is no administrator responsible for the entire network. The user on each computer determines which data on that computer is shared on the network.

Advantages of using peer to peer

• They are easy to configure
• Computers communicate easily.
• They don’t require additional server hardware or software
• Users can manage their own resources.
• They don’t require a network administrator
• They reduce total cost of network setup.

Disadvantages of using peer to peer

1. They provide a limited number of connections for shared resources.
2. Computers with shared resources suffer from sluggish performance.
3. They don’t allow for central management
4. Users are responsible for managing resources. These resources include data in shared directories, printers, fax cards, and so on.
5. They offer very poor security.

2.Domain based model or Client/server model

This is a network model that offers centralized access to services and devices. One computer plays the role of a server. It is the most common type of network architecture today that provides centralized data storage, security, manning of applications and network administration. Most servers operating system are Novel Netware, Windows NT, Apple talk, Linux, Banyan VINES etc…

Disadvantages

• Cost: – More expensive in terms of hardware and network operating system.
• Complexity: – Experienced system administrators are required to manage the systems.
• Dependence: – When server goes down, operations will cease across the network.

Advantages

1. They are best suited for 10 or more users.
2. Security: – All major server based systems provides sophisticated security.
3. Administration: – Servers are centralized making them easier to manage.
4. Stability: – Server based systems are designed to support a wide range of organization sizes. Additional servers are added to increase capacity.
5. Client server networks offer centralized backup where data can be stored in one server.
6. Flexibility – New technology can be easily integrated into the system.
7. Accessibility – Server can be accessed remotely and across multiple platforms.

Applications of Computer

 There are many applications of computers and which are used in various fields.

Below are the names of the fields where the applications of a computer are used.

• Education & Training centers
• Business
• Banking & Financial company
•  Entertainment
• Engineering
• Accounting
• Communications
• Digital Advertisement
• Pharmacy & Hospital
• Office
• Library
• Transporting
• Gaming
• CAD/CAM

Applications of Computer in Education

In the field of education too, the application of computer is being used to teach children in every school, college, the university today.

Through education applications, children are being taught in an even better way so that children are reading and understanding better. Through education applications, you can read and create digital books, digital notes. There are many applications of such education that run through the internet.

Today in every training center such as a computer training center, driving training center and many more training centers are being taught using training applications.

Applications of computer in Business

Computers are also being used in the field of business so that the business can be made more profitable and the business of businessman becomes even easier.

There are many business applications in the market today for business as well.

Through these business applications, you can completely monitor your business like - do calculations, give e-bill or paper bills to customers, do sales analyses, check price, check stock of an item, how much is left in stock now is.

Applications of computer in Banking & finance

Even in the banking sector, today all the work is being done in every bank with the use of a computer.

With the use of computers, the work of banks has become fast and convenient, due to which bank customers are also getting a lot of benefits.

Today every bank in the world is dependent on computers because every bank does its work from computers like - printing bank holder's passbook, opening new accounts, electronic fund transfers, e-banking, and many more. are done by computer. The basic work of a finance company is to give loans to its customers, before giving a loan, this company checks the credit score of that customer, after that, it decides whether to give a loan or not.

 Applications of Computer in Entertainment

Computers are also being used tightly in the field of entertainment.

Today, the computer is the only means of entertainment for people around the world, due to which people never get bored and the number of people who are being entertained by computers is increasing day by day. The VLC media player is an entertainment application and there are many other types of entertainment that are given below.

• YouTube
• Amazon Prime
• Netflix

These are all entertainment applications.

Applications of Computer in Engineering

Computers are also being widely used in the engineering sector.

Today the engineer is able to complete every one of his projects through the computer only.

Engineers used to make blueprints of their projects from sketches, which take them a lot of time, but today engineers make blueprints of their projects from computers, which saves them a lot of time.

For example, civil engineers design the map of a house, complex, mall with CAD (computer-aided design).

CAD (computer-aided design) is a 2D and 3D designing application.

Mechanical engineers also use designing applications to make model designs of vehicles.

 Applications of Computer in Communication

Even in the field of communication, people are able to communicate with each other only through computer applications.

Through communication application, whenever people want to talk, they can talk to anyone.

The specialty of these applications is that it delivers your message within a few seconds from which you send the message.

These communication applications will be used by almost all the people of the world.

Through these communication applications, you can communicate with text, voice, and video.

Human Brain vs Computer

 

Key Differences Between Brain and Computer

1. The brain can have 100 teraflops of memory with a density of 107 circuits per cm3 while computer memory has the 100 million megabytes with a density of 1014 bits per cm3. Memory in brain grows instantly just by connecting synaptic link whereas in a computer to scale the memory the chips need to be added.
2. Brain has the inbuilt backup system where the functioning pathways replace the damaged pathways. As against, backup systems are constructed manually in a computer.
3. The energy consumption in the brain is less than the computer.
4. To store information the brain uses electrochemical and electromagnetic form. Conversely, in a computer, the information is stored in the symbolic and numeric form.
5. In the brain, the information is transmitted with the help of chemicals to fire action potential in the neurons. On the contrary, the computer uses electrically coded signals to transmit the data.
6. The processing power of the brain is unlimited and provides online processing, but the brain processes information at slow speed because neurons are slow in action. In contrast, the processing power of computers is significant because of fast transistors.
7. The brain is self-organised while the computer is preprogrammed structure.

RISC Vs CISC

 

BASIS FOR COMPARISON	RISC	CISC
Emphasis on	Software	Hardware
Includes	Single clock	Multi-clock
Instruction-set size	Small	Large
Instruction formats	fixed (32-bit) format	Varying formats (16-64 bits each instruction).
Addressing modes used	Limited to 3-5	12-24
General purpose registers used	32-192	8-24
Memory inferences	Register to register	Memory to memory
Cache design	Split data cache and instruction cache.	Unified cache for instructions and data.
Clock rate	50-150 MHz	33-50 MHz
Cycles Per Instruction	Single cycle for all instructions and an average CPI < 1.5.	CPI between 2 and 15.
CPU Control	Hardwired without control memory.	Micro-coded using control memory (ROM).

 

Master Slave Flip Flop

Basically, this type of flip flop can be designed with two JK FFs by connecting in series. One of these FFs, one FF works as the master as well as other FF works as a slave. The connection of these FFs can be done like this, the master FF output can be connected to the inputs of the slave FF. Here slave FF’s outputs can be connected to the inputs of the master FF.

In this type of FF, an inverter is also used addition to two FFs. The inverter connection can be done in such a way that where the inverted CLK pulse can be connected to the slave FF. In other terms, if CLK pulse is 0 for a master FF, then CLK pulse will be 1 for a slave FF. Similarly, when CLK pulse is 1 for master FF, then CLK pulse will be 0 for slave FF.

 

Master-Slave FF Working

Whenever the CLK pulse goes to high which means 1, then the slave can be separated; the inputs like J & K may change the condition of the system.

The slave FF can be is detached until the CLK pulse goes to low which means to 0. Whenever the CLK pulse goes back to low-state, then the data can be transmitted from the master FF to the slave FF and finally, the o/p can be obtained.

At first, the master FF will be triggered at a positive level whereas the slave FF will be triggered at a negative level. Due to this reason, the master FF responds first.

If J=0 & K=1, then the output of the master FF ‘Q’ goes to the input K of the slave FF & the CLK forces the slave FF to RST (reset), therefore the slave FF copies the master FF.

If J=1 & K=0, then the of the master FF ‘Q’ goes to the input J of the slave FF & the CLK’s negative transition sets the slave FF, and copies the master.

If J=1 & K=1, then it toggles over the CLK’s positive transition & therefore the slave toggles over the CLK’s negative transition.

If both the J & K are 0, then the FF can be immobilized & Q remains unmovable.

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SCANNERS

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color. 

 

HOW SCANNERS WORK
Scanners operate by shining light at the object or document being digitized and directing the reflected light (usually through a series of mirrors and lenses) onto a photosensitive element. In most scanners, the sensing medium is an electronic, light-sensing integrated circuit known as a charged coupled device (CCD). Light-sensitive photosites arrayed along the CCD convert levels of brightness into electronic signals that are then processed into a digital image.

A scanner consists of a flat transparent glass bed under which the CCD sensors, lamp, lenses, filters and also mirrors are fixed. The document has to be placed on the glass bed. There will also be a cover to close the scanner. This cover may either be white or black in colour. This colour helps in providing uniformity in the background. This uniformity will help the scanner software to determine the size of the document to be scanned.

The lamp brightens up the text to be scanned. Most scanners use a cold cathode fluorescent lamp (CCFL).

A stepper motor under the scanner moves the scanner head from one end to the other. The movement will be slow and is controlled by a belt. The scanner head consists of the mirrors, lens, CCD sensors and also the filter. The scan head moves parallel to the glass bed and that too in a constant path. As deviation may occur in its motion, a stabilizer bar will be provided to compromise it. The scan head moves from one end of the machine to the other. When it has reached the other end the scanning of the document has been completed. For some scanners, a two way scan is used in which the scan head has to reach its original position to ensure a complete scan.

As the scan head moves under the glass bed, the light from the lamp hits the document and is reflected back with the help of mirrors angled to one another. According to the design of the device there may be either 2-way mirrors or 3-way mirrors. The mirrors will be angled in such a way that the reflected image will be hitting a smaller surface. In the end, the image will reach a lens which passes it through a filter and causes the image to be focussed on CCD sensors. The CCD sensors convert the light to electrical signals according to its intensity. Take a look at the diagram given below.

The electrical signals will be converted into image format inside a computer. This reception may also differ according to the variation in the lens and filter design. A method called three pass scanning is commonly used in which each movement of the scan head from one end to another uses each composite colour to be passed between the lens and the CCD sensors. After the three composite colours are scanned, the scanner software assembles the three filtered images into one single -colour image.