MODULE-4-ITEC_101

Computer Architecture

The system attributes that have a direct impact on the logical execution of a program, including the instruction set, data representation, input/output mechanism, and memory addressing techniques.

Computer Architecture

the science and art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals

Computer Organization

The operational units and their interconnections that realize the architectural specifications, including control signals, interfaces between the computer and peripherals, and memory technology.

Generations

a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies

5 Generations of Computer

First Generation (1946-1959, vacuum tube based)

Second Generation (1959-1965, transistor based)

Third Generation (1965-1971, integrated circuit based)

Fourth Generation (1971-1980, VLSI microprocessor based)

Fifth Generation (1980-onwards, ULSI microprocessor board)

13, 6, 6, 9

Central Processing Unit (CPU)

The main component of a computer system that performs most of the processing inside the computer.

Malware

Malicious software designed to disrupt, damage, or gain unauthorized access to computer systems or data.

Cybersecurity Threats

Potential risks and attacks that can compromise the security of computer systems and data, such as viruses, worms, ransomware, and phishing.

Encryption

The process of converting information into a code to prevent unauthorized access or data theft.

Authentication

The process of verifying the identity of a user or system to ensure authorized access.

Intrusion Detection

The process of monitoring and analyzing network traffic to detect and respond to unauthorized access or malicious activities.

TCP/IP

Transmission Control Protocol/Internet Protocol, the set of protocols used for transmitting data over the internet.

DNS

Domain Name System, the system that translates domain names into IP addresses.

HTTP/HTTPS

Hypertext Transfer Protocol/Secure Hypertext Transfer Protocol, the protocols used for communication between web browsers and web servers.

Microcomputer

The smallest general purpose processing system, examples include IBM PCs and Apple computers.

Desktops

Type of microcomputer that cannot be carried around.

Portables

Type of microcomputer that can be used while traveling.

Laptop

A portable computer similar to a desktop but smaller in size.

Notebook

A powerful computer smaller in size than a laptop and desktop.

Palmtop (Hand held)

Also known as a personal digital assistant (PDA), a small computer that can be held in hands and used for word processing, spreadsheets, hand writing recognition, game playing, faxing, and paging.

Wearable computer

A very small computer that can be worn on the body, used in fields like medicine.

Workstations

Computers used in large, high-resolution graphics screen built in network support, engineering applications, software development, and desktop publishing.

Minicomputer

A medium-sized computer more powerful than a microcomputer, designed to serve multiple users simultaneously.

Mainframe (Enterprise) computers

Computers with large storage capacities and very high speed of processing, used for simultaneous use by a number of users.

Supercomputer

Computers with extremely large storage capacity and computing speeds many times faster than other computers, used for large scale numerical problems in scientific and engineering disciplines.

Hardware

The physical devices of a computer, including CPU, memory, bus, and storage devices.

Software

The programs of a computer, including the operating system and applications.

Structure

The way in which components of a computer relate to each other.

Function

The operation of individual components as part of the structure.

Data processing

The ability of a computer to process data in various forms.

Data storage

The ability of a computer to store data temporarily or permanently.

Data movement

The ability of a computer to move data between itself and the outside world.

Control

The control of data processing, storage, and movement functions.

Functional unit

The five functionally independent main parts of a computer - input, memory, arithmetic logic unit (ALU), output, and control unit.

Input unit

The part of a computer that accepts coded information from input devices.

Memory unit

The part of a computer that stores programs and data, divided into primary memory and secondary memory.

Word

A unit of data of a defined bit length that can be addressed and moved between storage and the computer processor.

Memory access time

The time required to access one word in memory.

Primary memory

The memory exclusively associated with the processor, where programs are stored while being executed.

Secondary memory

Memory used for storing large amounts of data and programs that are accessed infrequently.

Random-access memory (RAM)

Memory that can be reached in a short and fixed amount of time after specifying its address.

Read-only memory (ROM)

Memory that is only readable by the user and its contents cannot be altered.

Caches

Small, fast RAM units that are tightly coupled with the processor to achieve high performance.

Arithmetic Logic Unit (ALU)

The part of a computer processor where arithmetic and logical operations are executed.

Control Unit

The component of a computer that sends signals to other units and senses their states.

Output Unit

The part of a computer system that sends processed results to the outside world, such as printers, speakers, and monitors.

Software

Programs that are executed to perform various functions, such as receiving and interpreting user commands, running application programs, and operating systems.

System Software

Collection of programs that help run the computer hardware and system, including device drivers, operating systems, servers, utilities, and compilers.

Application Software

Software that allows end users to accomplish specific tasks, such as business software, computer games, databases, and word processing.

Malware

Malicious software used to breach a computer system's security policy, including viruses, worms, Trojan horses, logic bombs, and backdoors.

Virus

Malware that spreads by embedding copies of itself into files and is transported to the target through various means.

Worm

Malware that spreads by transmitting copies of itself via a network without the use of infected files.

Trojan Horse

Malware that is embedded in seemingly useful software, with an overt effect that hides its covert effect.

Logic Bomb

Malware that is triggered by specific events, such as a specific date or time, or the creation or deletion of a specific data item.

Backdoor

Malware that allows the initiator to gain access to the target without going through normal login and authentication procedures.

Security Attacks

Actions or techniques used to exploit vulnerabilities in a computer system's security.

Services

Functions or capabilities provided by a computer system to meet specific needs, such as authentication, encryption, and access control.

Mechanisms

Techniques or methods used to implement security services, such as firewalls, intrusion detection systems, and encryption algorithms.

Security attack

Any action that compromises the security of information owned by an organization.

Security mechanism

A mechanism that is designed to detect, prevent or recover from a security attack.

Security service

A service that enhances the security of the data processing systems and the information transfers of an organization.

Interruption

An attack on availability where an asset of the system is destroyed or becomes unavailable or unusable.

Interception

An attack on confidentiality where an unauthorized party gains access to an asset.

Modification

An attack on integrity where an unauthorized party not only gains access to but tampers with an asset.

Fabrication

An attack on authenticity where an unauthorized party inserts counterfeit objects into the system.

Passive attacks

Attacks that involve eavesdropping on or monitoring of transmissions without modifying the contents of the original message.

Active attacks

Attacks that involve modification of the data stream or the creation of a false stream.

Masquerade

An active attack where one entity pretends to be a different entity.

Replay

An active attack that involves the passive capture of a data unit and its subsequent transmission to produce an unauthorized effect.

Modification of messages

An active attack where some portion of a message is altered or the messages are delayed or recorded to produce an unauthorized effect.

Denial of service

An active attack that prevents or inhibits the normal use or management of communication facilities.

Computer security

The processes and mechanisms by which digital equipment, information, and services are protected from unintended or unauthorized access, change, or destruction.

Cryptography

The art or science encompassing the principles and methods of transforming an intelligible message into one that is unintelligible, and then retransforming that message back to its original form.

Cryptographic systems

Systems that are generally classified based on the type of operations used for transforming plain text to cipher text, the number of keys used, and the way in which the plain text is processed.

Encryption

The process of encoding a message so that its meaning is not obvious.

Decryption

The reverse process of encryption, transforming an encrypted message back into its normal, original form.

Cryptanalyst

A person who studies encryption and encrypted messages and tries to find the hidden meanings (to break an encryption).

Confusion

A technique in cryptography for ensuring that ciphertext has no clue about the original message.

Diffusion

A technique in cryptography that increases the redundancy of the plaintext by spreading it across rows and columns.

Substitution Cipher

A method of encryption where each plaintext character is replaced with a different ciphertext character.

Monoalphabetic Substitution Cipher

A type of substitution cipher where the relationship between the ciphertext symbol and plaintext symbol is 1:1.

Additive Cipher

A type of monoalphabetic substitution cipher where a key value is added to the plaintext.

Affine Cipher

A type of monoalphabetic substitution cipher where each letter in the alphabet is mapped to its numeric equivalent and encrypted using a mathematical function.

Polyalphabetic Substitution Cipher

A type of substitution cipher where each occurrence of a character may have a different substitution.

Auto Key Cipher

A polyalphabetic cipher where the key is a stream of subkeys used to encrypt the corresponding characters in the plaintext.

Playfair Cipher

A polyalphabetic cipher where the secret key is made of 25 characters arranged in a 5x5 matrix.

Vigenere Cipher

A polyalphabetic cipher where the key stream is the repetition of the initial secret key stream.

Transposition Cipher

A method of encryption where the positions of units of plaintext are shifted according to a regular system.

Keyless Transposition Cipher

A method of transposition cipher where the text is written into a table column by column and transmitted row by row.

Keyed Transposition Cipher

A method of transposition cipher where the plaintext is divided into groups and the characters in each group are permuted.

Authentication

The process of confirming a user's identity in computer systems.

Biometrics

Authentication method that relies on the user's biological makeup, such as retina or fingerprints.

Public Key Infrastructure (PKI)

Authentication method that uses digital certificates to prove a user's identity.

Intrusion Detection

The process of monitoring computer systems or networks for signs of security problems or unauthorized access.

Intrusion Detection Systems (IDSs)

Software or hardware products that automate the process of monitoring and analyzing events for signs of intrusions.

Information Sources

The different sources of event information used to determine whether an intrusion has taken place.

Analysis

The part of intrusion detection systems that organizes and makes sense of the events derived from the information sources, deciding when those events indicate that intrusions are occurring or have already taken place.

Response

The set of actions that the system takes once it detects intrusions, typically grouped into active and passive measures.

Strong Passwords

Different user ID/password combinations for different accounts, avoiding writing them down, and making passwords more complicated by combining letters, numbers, and special characters.

Firewall

The first line of cyber defense that blocks connections to unknown or bogus sites and keeps out some types of viruses and hackers.