BASICS OF COMPUTER BY: ISHITA VERMA USME, DTU What is a Computer? • Computer is an electronic device which can be programmed to carry out various Arithmetic and logical operations. DATA RAW FACTS INPUT PROCESS PROCESSING OF DATA PROCESSING INFORMATION PROCESSED DATA OUTPUT CHARACTERISTICS OF COMPUTER ADVANTAGES OF COMPUTER ▪ ▪ ▪ ▪ ▪ Very fast processing. High storage capacity Error Free Never gets tired Dynamic LIMITATIONS OF COMPUTER • • • Can not work by itself Can not take decisions Can not learn by experience EVOLUTION OF COMPUTERS • FIRST GENERATION COMPUTERS (1946-1952) ➢Used vacuum tubes. ➢Were very large in size and writing programs was very difficult. ➢Examples: ENIAC, EDVAC etc. • SECOND GENERATION COMPUTERS (1952-1964) ➢Used Transistors. ➢Were smaller in size with higher processing speed. ➢The concept of CPU, Memory, Programming languages and input output devices were developed during this time. • THIRD GENERATION COMPUTERS (1964-1970) ➢Used Integrated Circuits(ICs) popularly known as Chips. ➢Size got further reduced as ICs were much smaller in size. • FOURTH GENERATION COMPUTERS (1970-1990) ➢Used Large Scale Integrated Circuits (LSI) were used. ➢Personal Computer (PC) was developed during this time. • FIFTH GENERATION COMPUTERS (1990 onwards) ➢Used Very Large Scale Integrated Circuits (VLSI). ➢Concepts of Parallel processing and artificial intelligence were introduced during this time. TYPES OF COMPUTER • DIGITAL COMPUTER – This kind of computer take all the input data in the form of numbers. All commonly used computers are digital. • ANALOG COMPUTER – This kind of computer measure some physical quantity like weather, length of an object, amount of voltage etc and assigns them numeric values, which are further processed. • HYBRID COMPUTER – These computers use features of both Digital and analog computers. Digital Computers are further classified into : ➢Micro Computer – It is at the lowest end in terms of storage capacity and processing speed. Its CPU is a Microprocessor. Eg Desktop PCs and laptops. ➢Mini Computer – These are of medium power, more than a Micro computer but less than a Main frame computer. ➢Main Frame Computer – These operate at very high speed, have very large storage capacity and can handle many users at a time. ➢Super Computer – These are the fastest and the most expensive computers. BLOCK DIAGRAM OF COMPUTER INPUT DEVICE – These are the devices which are used to give data to the computer. output DEVICE – These are the devices which are used to display output from the computer. Projector Central Processing Unit (CPU) • This is the brain of computer which does all the processing of instructions. • It has 2 parts: CONTROL UNIT (CU) and ARITHMETIC LOGIC UNIT (ALU). • CU will fetch the instruction from the memory and decode it. • ALU will perform the required Arithmetic and logical operations, for execution of instruction. MEMORY • There are primarily 2 types of memory in computer: Main Memory (Primary Memory) and Secondary Memory • Main Memory : It is this memory with which the CPU can interact directly. It is further divided into 2 parts: RAM AND ROM ➢ RAM : Random Access Memory is volatile in nature i.e. its contents get lost when the power is turned off. ➢ROM : Read Only Memory is nonvolatile in nature i.e. its contents are not lost even when the power is turned off. • Secondary Memory : Also called as Auxiliary Memory, it is used to increase the limited storage capacity of main memory. • DIFFERENCE BETWEEN PRIMARY MEMORY AND SECONDARY MEMORY PRIMARY MEMORY SECONDARY MEMORY 1. It is faster to access. 1. It is time consuming to access as the program needs to be first brought to main memory in order to be executed. 2. It is costly. 2. It is cheaper. 3. It is also called as MAIN MEMORY. 3. It is also called as Auxilliary memory. 4. It is temporary memory or volatile in nature. 4. It is non-volatile in nature. 5. It has limited storage capacity. 5. The storage capacity has is unlimited. • DIFFERENCE BETWEEN RAM AND ROM RAM ROM 1. It is called Random Access Memory. 1. It is Read Only Memory. 2. The contents of this memory are lost as soon as power is turned off. 2. The contents of this memory are permanent in nature. 3. This is expensive. 3. This is cheaper. 4. This memory allows both reading and modification. 4. This memory allows only reading but not modification. PROTECTION & SECURITY • Goals of Protection and Security: The Primary goal of ensuring protection and security is to prevent our computer system and confidential data against cybercrime. Cybercrime means criminal activities which are carried out using computer and internet. The most common types of cybercrime are: ➢Phishing: It is a fraudulent attempt usually made through E mail, phone calls, SMS etc seeking your personal and confidential details. ➢Cyber theft: It is the stealing of financial and/or personal information through the use of computers for making its fraudulent or other illegal use. Cybertheft includes hacking of a bank’s computer records to wrongfully credit one account and debit another and interfere with a copyright by wrongfully sending protected material over the internet. ➢Cyber stalking: It is the act of using internet to make someone else afraid or concerned about their safety. Most of the time the stalkers use social Media, internet databases, search engines and other databases to cause terror and anxiety to others. ➢Malware: Also called as Malicious software, has been intentionally designed to cause harm to someone’s computer system or network. It includes Computer Virus, Worm, Trojan Horse etc. ➢Spyware: It is a software which gets installed in a user’s computer without his knowledge and transfers all this surfing information along with personal information like bank account details, credit card number etc over the internet. It can also interfere with a user’s control of the system by installing additional software or redirecting web browsers. Virus, Worm and Trojan Horse • Virus: Computer virus is also like a human virus. It attaches itself to a program or a file and spreads from one computer to others through that file/program. It requires the file to be executed in order for the virus to cause the harm i.e the virus may be lying in your system but till the time you don’t execute the infected file, it will not be able to harm your system. • Worm: Worm is similar to a virus in its design but it does not require any human action in order to cause the harm. It has the capability to replicate itself and then spread through the network without being attached to a file. One example is a worm can make copies of itself and then send to every person in your email address book. • Trojan Horse: It is a destructive program which looks like a genuine application and thus gives malicious users/hackers access to your system to steal away your personal and confidential data. Steps to control Cybercrime ➢Use of passwords: We should always keep our system and data password protected. Passwords should be strong i.e a mix of alphabets, numbers and symbols etc so that they are difficult to guess. Also they should be changed frequently. ➢Use of Antivirus software: Antivirus software also called as Anti-malware is a computer program developed to prevent, detect and remove malware from our systems. Some common Antivirus software are Norton antivirus, Kaspersky etc ➢Use of Firewall: It is a network security device which monitors data coming in and going out of a network and decides whether to allow or block some data packets based on a defined set of rules. Firewalls can be either hardware or software. If they are hardware then they are installed at the entry point of a network. If they are software then they will be installed on user’s computers. ➢Use of Encryption and Decryption: Encryption is the process of converting the plaintext into something that looks random and meaningless, called as Ciphertext. Decryption is the process of obtaining the plaintext back from ciphertext. There are different Encryption algorithms which can be used for encrypting the data. The goal of every Encryption algorithm is to make it impossible to get the plaintext back from the ciphertext. Whenever any confidential data is to be sent over a network it is always encrypted at the sender’s end and then transmitted over the network. This makes the data secure from hackers. Everytime we use ATM, make payments online or access our bank account details, the data is always transmitted over the internet in encrypted form only. Cyber laws • Cyber laws are the laws which safeguard the citizens against cyercrime like Cyber bullying, hacking, Identity theft, Cyber stalking etc. • The Information Technology Act, 2000 (also known as ITA-2000, or the IT Act) is an Act of the Indian Parliament (No 21 of 2000) notified on 17 October 2000. It is the primary law in India dealing with cybercrime . • The main objectives of IT Act 2000 are as follows: ➢ to provide legal recognition to all electronic transactions. ➢To give legal recognition to digital signatures. ➢To give legal recognition to keeping of accounting books in electronic form by banks and other organizations. ➢To provide online privacy and prevent cyber crimes.
