BSc CSIT (TU) Science Introduction to Information Technology (BSc CSIT, CSC109) Question Paper 2078 Nepal

History and Evolution of Computers (Five Generations)

Computers have evolved through five generations, each defined mainly by the electronic switching technology used.

First Generation (1940–1956) — Vacuum Tubes

• Used vacuum tubes for circuitry and magnetic drums for memory.
• Very large, expensive, generated enormous heat, and consumed a lot of power.
• Programmed in machine language (binary); used punch cards for input.
• Examples: ENIAC, EDVAC, UNIVAC-I, IBM-701.

Second Generation (1956–1963) — Transistors

• Transistors replaced vacuum tubes — smaller, faster, cheaper and more reliable.
• Used magnetic core memory; introduced assembly language and early high-level languages (FORTRAN, COBOL).
• Examples: IBM-1401, IBM-7094, CDC-1604, UNIVAC-1108.

Third Generation (1964–1971) — Integrated Circuits (ICs)

• Many transistors placed on a single silicon chip (IC) greatly reduced size and cost.
• Introduced keyboards, monitors, operating systems and multiprogramming.
• Examples: IBM-360 series, PDP-8, ICL-2900.

Fourth Generation (1971–present) — Microprocessors (VLSI)

• VLSI technology put the entire CPU on a single chip — the microprocessor.
• Gave rise to personal computers, GUIs, networks and the Internet.
• Examples: Intel 4004/8088, IBM-PC, Apple Macintosh.

Fifth Generation (present and beyond) — Artificial Intelligence

• Based on ULSI, parallel processing, and Artificial Intelligence.
• Aims at natural language processing, expert systems, robotics, and quantum/parallel computing.
• Examples: modern AI machines, IBM Watson, robots, supercomputers using AI.

Conclusion: Each generation made computers smaller, faster, cheaper, more reliable and more powerful, moving from vacuum tubes toward intelligent machines.

System Software and Types of Operating Systems

System Software

System software is a set of programs that controls and manages the computer hardware and provides a platform on which application software can run. It acts as an interface between the user/application and the hardware. Examples include the operating system, device drivers, language translators (compiler, assembler, interpreter), and utility programs.

Operating System

An Operating System (OS) is the most important system software that manages resources such as the CPU, memory, files and I/O devices, and provides services to the user (e.g., Windows, Linux, macOS).

Types of Operating Systems (with examples)

1. Batch Operating System — Jobs with similar needs are grouped into batches and executed without user interaction. Example: early IBM mainframe OS.
2. Time-Sharing (Multitasking) OS — CPU time is shared among many users using time slices so each gets quick response. Example: UNIX.
3. Multiprocessing OS — Uses two or more CPUs to execute processes simultaneously for higher throughput. Example: Linux, Windows Server.
4. Real-Time OS (RTOS) — Responds to inputs within a strict time limit; used in time-critical systems. Example: VxWorks, RTLinux (used in robotics, missiles, medical systems).
5. Distributed OS — Manages a group of independent computers connected by a network and makes them appear as a single system. Example: Amoeba, LOCUS.
6. Network OS — Runs on a server and lets multiple clients share resources over a network. Example: Windows Server, Novell NetWare.
7. Single-/Multi-user OS — Single-user (MS-DOS) supports one user; multi-user (UNIX) supports many simultaneously.

Conclusion: System software, led by the operating system, makes hardware usable, and different OS types are chosen according to the application's requirements.

Data Communication, Transmission Modes and Switching Techniques

Data Communication

Data communication is the exchange of data (in digital or analog form) between two or more devices through a transmission medium such as a cable or wireless link. Its basic components are the sender, receiver, message, transmission medium, and protocol.

Modes of Data Transmission (Direction of Flow)

1. Simplex — Data flows in one direction only; one device transmits, the other only receives. Example: keyboard to CPU, TV broadcast.
2. Half-Duplex — Data flows in both directions but only one at a time. Example: walkie-talkie.
3. Full-Duplex — Data flows in both directions simultaneously. Example: telephone.

(Transmission may also be serial — one bit at a time, or parallel — many bits at once; and synchronous or asynchronous based on timing.)

Switching Techniques

Switching is the method of routing data from source to destination through intermediate nodes.

1. Circuit Switching — A dedicated physical path is established between sender and receiver for the entire session before communication begins. Example: traditional telephone network. Reliable but wastes bandwidth when idle.
2. Message Switching — The whole message is sent and stored at each intermediate node, then forwarded (store-and-forward). No dedicated path; suited to non-real-time data. Example: telegram, early email.
3. Packet Switching — The message is divided into small packets, each routed independently and reassembled at the destination. Efficient use of bandwidth. Example: the Internet (TCP/IP).
   • Datagram approach: each packet routed independently.
   • Virtual circuit approach: a logical path is set up; all packets follow it.

Conclusion: Data communication enables information exchange; the transmission mode defines direction of flow, while switching techniques (circuit, message, packet) determine how data is routed across the network, with packet switching being the basis of the modern Internet.

Hardware vs. Software

Hardware is the set of physical, tangible components of a computer that can be seen and touched, while software is a set of programs/instructions (intangible) that tells the hardware what to do.

Conclusion: Hardware and software are complementary — hardware is the body and software is the soul of a computer; both are required for a computer to function.

Convert $(1101101)_2$ to Decimal and Octal

(a) Binary to Decimal

Multiply each bit by its positional weight ($2^n$) and add:

(b) Binary to Octal

Group the bits into sets of 3 from the right and convert each group:

Check: $1\cdot8^2 + 5\cdot8^1 + 5\cdot8^0 = 64 + 40 + 5 = 109$ ✓

Utility Program

A utility program (utility software) is a type of system software designed to perform specific maintenance, management and optimization tasks that help the operating system keep the computer running smoothly and efficiently. It supports, configures and maintains the system rather than doing end-user application work.

Functions

• Manage, maintain and protect files, disks and the system.
• Improve performance and security.

Examples

• Antivirus software (e.g., Avast, Kaspersky) — detects and removes viruses.
• Disk Defragmenter — reorganizes fragmented files on a disk.
• Disk Cleanup — removes temporary/unwanted files.
• Backup and Restore tools.
• File Compression tools (e.g., WinZip, WinRAR).
• Disk Scanner / ScanDisk / CHKDSK — checks the disk for errors.
• Disk formatting and partitioning tools.

Secondary Storage Devices

Secondary storage (auxiliary/external memory) is non-volatile storage used to permanently store data, programs and the operating system even when the computer is switched off. It is cheaper, larger in capacity and slower than primary memory (RAM), and the CPU cannot access it directly.

Types with Examples

1. Magnetic Storage — stores data using magnetization.

   • Hard Disk Drive (HDD): large-capacity fixed disk, e.g., 1 TB internal disk.
   • Magnetic Tape: sequential storage used for backup.

2. Optical Storage — uses a laser to read/write data on a disc.

   • CD-ROM (~700 MB), DVD (~4.7 GB), Blu-ray Disc (~25 GB+).

3. Solid-State / Semiconductor Storage — uses flash memory, no moving parts, fast.

   • SSD (Solid State Drive), USB Flash/Pen Drive, Memory (SD) Cards.

Conclusion: Secondary storage devices such as hard disks, CDs/DVDs, SSDs and flash drives provide permanent, high-capacity storage of data beyond the limited and volatile primary memory.

Protocol and the TCP/IP Protocol Suite

Protocol

A protocol is a set of rules and conventions that govern how data is formatted, transmitted, received and interpreted between communicating devices in a network. It defines syntax, timing, error control and sequencing so that different devices can communicate reliably. Examples: TCP, IP, HTTP, FTP.

TCP/IP Protocol Suite

TCP/IP (Transmission Control Protocol / Internet Protocol) is the standard set of protocols used to interconnect networks and run the Internet. It is organized into four layers:

• TCP provides connection-oriented, reliable delivery (acknowledgement, sequencing, error control).
• IP handles logical addressing (IP address) and routing of packets across networks.

Conclusion: A protocol is a communication rule, and TCP/IP is the four-layer protocol suite that forms the foundation of the Internet.

Internet vs. Intranet

The Internet is a global, public network that connects millions of computers worldwide, accessible to everyone. An intranet is a private network of an organization that uses Internet technologies but is restricted to authorized members only.

Conclusion: The Internet is a public worldwide network, whereas an intranet is a secure, private network built using the same technology for use within a single organization.

Data Model and Its Types

Data Model

A data model is a conceptual/abstract framework that describes how data is structured, stored, organized and related, along with the constraints and operations on that data in a database. It defines the logical design of a database and how the relationships among data are represented.

Types of Data Models

1. Hierarchical Data Model — Organizes data in a tree-like structure with a parent–child (one-to-many) relationship; each child has only one parent. Example: IBM IMS.
2. Network Data Model — Data organized as a graph; a child can have multiple parents (many-to-many relationships) using records and links. Example: IDS.
3. Relational Data Model — Data stored in tables (relations) of rows and columns; relationships established through keys. Most widely used. Example: MySQL, Oracle.
4. Object-Oriented / Object Data Model — Data represented as objects (data + methods), supporting inheritance and encapsulation. Example: ObjectDB.
5. Entity-Relationship (E-R) Model — Represents data as entities, attributes and relationships; mainly used for conceptual database design.

Conclusion: A data model defines the logical structure of a database, and the main types are hierarchical, network, relational, object-oriented and entity-relationship models.

Applications of Multimedia in Education

Multimedia is the integrated use of text, graphics, audio, video and animation to present information. In education it makes learning more interactive, engaging and effective. Its main applications are:

1. Computer-Based Training (CBT) / e-Learning — Interactive lessons and tutorials let students learn at their own pace.
2. Virtual Classrooms & Online Courses — Audio/video lectures and screen-sharing support distance and remote learning.
3. Simulations and Virtual Labs — Animations and 3-D simulations explain complex concepts (e.g., chemical reactions, human anatomy, physics experiments) that are hard to show in a real classroom.
4. Edutainment — Educational games and interactive content make learning enjoyable, especially for children.
5. Digital Encyclopedias and e-Books — Combine text, images, audio and video as rich reference material.
6. Presentations and Visualization — Teachers use slides, videos and animations to explain topics clearly and improve retention.

Conclusion: Multimedia improves understanding, motivation and accessibility in education by appealing to multiple senses and supporting self-paced, interactive learning.

Short Note: Data Encryption

Data encryption is the process of converting plain text (readable data) into an unreadable form called cipher text using an algorithm and a key, so that only authorized parties who possess the correct key can convert it back (decrypt) to its original form. It is a fundamental technique for ensuring data security, confidentiality and privacy, especially during transmission over networks.

Key Terms

• Plain text: original readable message.
• Cipher text: scrambled, unreadable message.
• Encryption: plain text → cipher text.
• Decryption: cipher text → plain text.
• Key: secret value used to encrypt/decrypt.

Types

1. Symmetric (Private-Key) Encryption — The same key is used for both encryption and decryption. Fast but key sharing is a problem. Example: DES, AES.
2. Asymmetric (Public-Key) Encryption — Uses a pair of keys (public key to encrypt, private key to decrypt). More secure for key exchange. Example: RSA.

Advantages

• Protects data confidentiality and integrity.
• Prevents unauthorized access and ensures secure communication (e.g., in online banking, HTTPS).

Conclusion: Data encryption secures information by transforming it into cipher text, and is essential for safe storage and transmission of sensitive data.