Category Archives: COMPUTER TECHNOLOGY

about computers

LANGUAGE PROCESSORS?

Language processors


Programmers write codes in high-level language however the computer does not understand any other language other than its own machine language of zero and one that is binary language.

Therefore it is necessary to process the High-level language into binary language so it is done by the language processors

  • ASSEMBLER

This language processor converts the program written in assembly language into machine language

  • INTERPRETER

This language processor converts high-level language program into machine language(binary) by converting and executing line by line.

If there is any error in any line it reports at the same time and program execution can not resume until the error is rectified.

Advantage

  • For error debugging, an interpreter is useful as it reports the error at the same time.

Disadvantage

  • But once errors are removed usage of memory takes place as interpreter must always be present in memory
  • COMPILER

It also converts the High-level language into machine language(binary) but conversion method is different it converts in one go and reports all the error of program after conversion along with line numbers.

Advantage

  • After all, error is are removed, the program is recompiled and after that, the compiler is not needed in the memory as the object program is available

Disadvantage

  • Interpreter is much better for error removal than compiler

 

WHAT IS FIRMWARE?

Firmware

Firmware is basically a software type which is pre-installed in the device non volatile memory(like ROM) from the device manufacturer.

We can not change or access the firmware easily

It can be updated if the manufacturing company allow us to update.The update is for bug fixes or adding new features to the device

It can be hacked

Why it is required

  • It defines the functionality of the device
  • it is controlling software for modern electronic
  • used to run an application program on the device
  • used to protect the device from malware

Guide to some of Programming languages ?

Complete Guide To Perl, PHP, and Python?

These are very popular programming language each with its own advantage and disadvantages.I am publishing this article so that the people will get a brief guide to these languages and it will be helpful for them who wants to learn these languages

Perl

Perl is a general purpose language, high-level dynamic programming language.currently, the popular version is Perl 5.It is derived from different languages like c.

It is useful for web development, system administration, network programming and game development.

Advantages

  • In Perl, there are many ways to do the same thing
  • It is portable and available for all platforms
  • since Perl is very old language it has vast community support
  • Perl code is very short and there is a whole set of one line code available
  • It is very good at handling regular expression
  • Perl CPAN( Comprehensive Perl Archive Network) provides a huge number of modules and tested code most of which are completely free
  • It should be used depending upon the use case.It can be used as a functional language, sometimes object oriented, Procedural.It depends on programmer how to use

Disadvantages

  • Since its syntax is complex sometimes new programmers find it difficult to understand it, because the same code can be written in many different ways
  • It has poor documentation for object oriented approach compared to Python
  • It is slow as compared to other scripting languages

Popular Frameworks and Popularity

  • Through Perl is old language, its growth has been slow compared to some other languages
  • Catalyst, dancer, and mojolicious are some of the popular frameworks

Basic Syntax

#!/usr/bin/perl

Print “hello programmers”;

File extension is  .pl

 

PHP(PHP Hypertext Preprocessor)

It is also General purpose language but it is mainly used for web development.It is server side scripting language very popular for back end web development compared to other languages.Used by some big companies like Facebook, YouTube, google etc.

The latest version is 7.1

Advantages

  • Most people prefer PHP when it comes creating dynamic web pages because it is easier to set local host and most of Web Hosting providers offer to build in PHP support
  • It is easy to use.The syntax is almost similar as that of c language.Anyone can adopt it
  • There are lot of frameworks available for PHP and has good community support
  • It is stable
  • code maintenance is quick
  • Has strong database support

Disadvantages

  • Some libraries written in PHP are procedural, so it is difficult for programmers from object oriented background
  • Since it is open source security is the main challenge.As code is available to all hackers can easily find weakness in code
  • Its error handling capabilities are poor

Popular Frameworks and Popularity

  • PHP is still very popular and one of the top language used by web developers to create dynamic websites
  • Laravel, Symfony, cakePHP are some of the popular frameworks

Basic Syntax

<? php

echo “hello”;

?>

File extension is .php

Python

It is a general purpose high-level language designed by Guido Van Rossum in 1980.It is easy to learn.It is very popular nowadays.It can be used for web development, mobile game development, mobile apps development, cloud computing, data analytics.

It uses indentation which eliminates need of curly brackets and colon

Advantages

  • It is well documented
  • can be used game development which is different from other languages
  • easier to learn than c and c++
  • The code is short compared to other languages

Disadvantages

  • indentation is an issue sometimes people find irritating as the code does not work properly
  • slower than c and c++

Popular frameworks and popularity

  • very popular in current scenario
  • popular frameworks are Django, web2py, flask

Basic Syntax

print “hello”

File extension is .py

So which is the best language among these to learn and use?

There is no specific answer to this question because it depends on what you want to do and how can you do it efficiently

In my opinion, if web development is first priority then PHP should be first priority

For test automation and scripting python and Perl is popular

You should learn all these languages and use them based on the situation and need

Beginners can start with python as it is easier to learn later on they can learn PHP and Perl

Basic logic for all programming language is same only syntax differs and if you have learned any one programming language it is easier to shift into the other languages.

 

Computer Memory?

Memory

Memory is Just like human brain it is used to store data and instruction. Computer memory is a storage space in the computer where data is to be processed and instructions required for processing are stored.

Types of computer memory

  • Main Memory- Main memory-Main memory is fast, it has Limited capacity and data is lost when power is switched off.
  • Secondary memory-It is an external memory and non-volatile in nature it is slower than main memory and used for storing data permanently.It is present even if power is switched off.

Units of memory

A computer stores and process data in the form of binary numbers.A binary is either a 0(off voltage) or 1(on voltage) and is known as bit(short form of binary digit)

4 bits=1 nibble

8 bits=1 byte

1024 bytes=1 kilobyte(KB)

1024 KB=1 megabyte(MB)

1024 MB=1 gigabyte(GB)

1024 GB=1 Terabyte(TB)

1024 TB=1 petabyte(PB)

Parts of main memory

RAM-Random access memory

  • It is volatile memory i.e it only last till computer is powered on
  • All programmers embed their programs in RAM
  • It is fast than secondary storage
  • It is temporary

ROM-Read only memory 

  • Data stored in ROM is not erased even if power is switched off
  • It is permanent and nonvolatile
  • The data in ROM can’t be changed by user as it is embedded inside the processor
  • Programs related to operating system are stored in ROM
  • It is used to tell the computer how to load the operating system when it is switched on or rebooted

CACHEThis memory I have explained in deep in my previous post you can visit by clicking on                    the link 

Parts of secondary memory

Magnetic media

Hard drive

  • Used to store large amount of data and stores data in one or more circular magnetic disks
  • Permanent storage
  • rewritable and erasable
  • slower than RAM and ROM
  • Usually fixed inside the computer

Optical media

Compact disk

  • Can be used to store information and can’t be used to store data
  • have low storage space

Flash Memories/drives

  • Pendrive and SD card are flash memories
  • have a large storage capacity
  • smaller in size
  • most use memory today
  • easily to carry

 

 

WHAT IS WANNACRY RANSOMWARE ATTACK?

What is Ransomware attack?

First, we need to understand what is ransomware attack-

It is a malware which locks or encrypt all your data stored on your computer hard disk and the hackers demand money to unlock your data as they will provide decryption key if you send money but it is not necessary.It all depend on hackers choice.

Some Examples of ransomware are:

  • cryptolocker-2013
  • cryptowall-2014
  • wannaCry-2017

WannaCry attack

It is one of the biggest ransomware attacks and latest attack started in may 2017 on a large scale and within a day 230000 devices were affected with this.

It was a Trojan virus- It is any malicious computer program which is used to hack into a                                                       computer by misleading users of its true intent

What can Trojan do:

  • Delete data
  • copying data
  • blocking data
  • modifying data
  • encrypting data

Some Facts about WannaCry Ransomware

  • It is one of the largest cyber attacks
  • The hackers demanded money in Bitcoins.
  • The amount was around $300-$600
  • The amount was doubled if you will not able to pay within 7 days
  • over 150 countries 230000 devices were infected
  • By wannaCry the hackers gathered around 90000 dollars(approximately)
  • Some big companies like FedEx, Deutsche Bahn, Britain national health service etc were affected
  • It was targeting only Microsoft windows operating systemWindows 8, XP, vista and older versions

Reasons for wannaCry

NSA(National security agency) of united states have some list of bugs of Windows operating system That file of NSA was leaked in a dark web of internet by a group of hackers and then  the hackers designed wanna crypt ransomware by taking advantage of Microsoft Windows bugs

To counter the effect Microsoft issued patches update but many people can’t access that patches in old and pirated Windows

How To Protect Your computer?

  1. Downloading latest updates of patch provided by Microsoft or keeping the operating system updated
  2. Keeping the paid antivirus software with the latest version of security
  3. Never open suspicious links in Email
  4. Keep your useful data backed up in external hard drive
  5. Don’t visit unsafe and unreliable websites
  6. Disconnect the internet when not required
  7. use original windows instead of pirated
  8. Never download .exe attachment from your email
  9. Keep note the extension in ransomware is like .mp4.exe , .doc.exe  etc
  10. Use Firewall and keep it on
  11. Disable remote sharing option in windows
  12. Use original software

WHAT IS CACHE MEMORY?

CACHE MEMORY

Cache memory is a part of main memory(primary memory).It is used in modern high-speed CPU to hold temporarily those portion of contents of main memory which are currently in use.Cache memory is integrated directly within CPU chip or placed on a separate chip that has bus interconnected with CPU.

It is faster memory among all 3 computer memories and has least capacity(around 2 MB to 12 MB). It reduces accessing time as when a user wants to get a part of data cache sends the copied data instead of Main memory.

Types

Level 1: Fastest among all built in inside the processor

Level 2: Can be inside the processor or near to processor on a separate Integrated circuit connected with a bus so that processor can  access cache fast

Level 3: It is separate memory having double speed than RAM but it is shared with all the cores of a processor

Why is cache required?

The Processor has to use much instruction and have to read/write much data.The frequently used data is stored in cache memory so that when a processor needs to execute some instruction it will make the process faster as the processor will fetch the required data from the cache instead of RAM if the data is present in cache otherwise it will take from the Random access memory.

NOTE:

  • It helps the processor to work fast
  • It can not be upgraded afterward

Cache Latency?

If the required file is not present in the cache so in this case the processor process is delayed and this delay in a process is known as Cache latency.

Cache in Android?

It is temporary data stored in your device memory by an application.It is stored temporarily in your device hard drive so that when you visit same application again your data is not consumed and the process becomes faster.

You can also clear the cache files in your android device

WHAT ARE COMPUTER COOKIES ?

COOKIES IN WORLD WIDE WEB

It is a small piece of data sent from a website and stored on the user computer by the web browser while the user is browsing the internet. They are designed to record user browsing activity or recording which pages are visited in past.

Some facts about cookies

  • The size of cookie is less than 4 KB
  • cookies files are stored in the cache memory
  • It user choice to enable or disable the cookies
  • Have ever wondered how a product advertisement is visible to you on any website which you have been interested in or seen previously on any other website                                      for example: if  you were searching a product on an eCommerce website and you did not buy it so the advertisement of that product will be visible to in other websites like social networking website etc. This is done with help of cookie stored on your device by the web browser
  •  It helps a website to present data to user in a user-friendly manner as if you visit the same website next time it can display the recommended results to the user

Why are cookies harmful?

  • cookies are not stored in encrypted format
  • 3rd party cookies i.e cookies from different website can leak the privacy of the user
  • Your login info that you have filled can be leaked like credit card details, name, address etc
  • so it is recommended to disable the third party cookies and malicious website cookies from browser settings.