BSc CSIT (TU) Science Introduction to Information Technology (BSc CSIT, CSC109) Question Paper 2080 Nepal

Definition of a Computer

A computer is an electronic device that accepts data as input, processes it according to a set of stored instructions (a program), produces meaningful information as output, and can store data and results for future use. It follows the Input → Process → Output (IPO) cycle under the control of a stored program.

Characteristics of a Computer

1. Speed – Performs millions/billions of operations per second (measured in MIPS, MHz/GHz, nanoseconds).
2. Accuracy – Produces error-free results; mistakes are usually due to wrong input or programs (GIGO – Garbage In, Garbage Out).
3. Diligence – Works continuously without fatigue, boredom, or loss of concentration.
4. Versatility – Can perform many different types of tasks (calculation, document editing, gaming, communication).
5. Storage Capacity – Stores huge volumes of data and retrieves it instantly.
6. Automation – Executes a sequence of instructions automatically without human intervention once a program starts.
7. Reliability – Gives consistent results over long periods.

Advantages of Computers

• High processing speed and accuracy.
• Large, reliable storage and quick retrieval of data.
• Automation of repetitive tasks, reducing manpower and cost.
• Facilitates communication (e-mail, internet) and access to information.
• Improves quality of work and supports decision making.

Limitations of Computers

• No intelligence (IQ = 0) – Works only as instructed; cannot think or decide on its own.
• No common sense / decision making – Cannot correct its own logical errors.
• Dependence on humans – Needs instructions and data supplied by users.
• No feelings or self-care – Cannot adapt to unforeseen situations.
• Vulnerability – Affected by power failure, viruses, and hardware faults.

Thus, a computer is a fast, accurate, and tireless machine, but it lacks intelligence and depends entirely on humans for instructions.

Types of Software

Software is a set of programs, procedures, and instructions that tell the computer hardware what to do. Software is broadly classified into System Software and Application Software (with Utility/Programming software as sub-categories).

1. System Software

Manages and controls the computer hardware and provides a platform for application software to run.

• (a) Operating System – Manages hardware resources, memory, files, and processes; provides the user interface. Examples: Windows, Linux, macOS, Android, Unix.
• (b) Device Drivers – Allow the OS to communicate with hardware devices. Examples: printer driver, graphics card driver.
• (c) Language Translators – Convert program code into machine code. Examples: Assembler, Compiler (GCC), Interpreter (Python).
• (d) Utility Software – Perform maintenance/support tasks. Examples: antivirus, disk defragmenter, backup tools, WinRAR.

2. Application Software

Designed to help users perform specific tasks.

• (a) General-purpose / Packaged software – Used by many users for common tasks. Examples: MS Word (word processing), MS Excel (spreadsheet), PowerPoint, web browsers.
• (b) Special-purpose / Custom software – Built for a specific organisation or task. Examples: payroll system, hospital management system, banking software, airline reservation system.

3. Programming Software (sometimes listed separately)

Tools used by programmers to develop software. Examples: compilers, debuggers, text editors, IDEs (VS Code, Eclipse).

Summary Table

In short, system software runs the computer, while application software helps the user accomplish work.

Computer Network

A computer network is a collection of two or more computers and other devices (printers, servers) interconnected by communication media so that they can share data, hardware/software resources, and communicate with one another. Networks are classified by size as LAN, MAN, and WAN.

OSI Reference Model

The OSI (Open Systems Interconnection) model, developed by ISO, is a 7-layer conceptual framework that standardises how data is transmitted between two devices over a network. Each layer performs specific functions and serves the layer above it. Data moves down the layers at the sender and up the layers at the receiver.

Function of Each Layer (brief)

1. Physical Layer – Deals with the actual transmission of raw bits (0s and 1s) over a physical medium; defines hardware specifications like cables, pins, and signalling.
2. Data Link Layer – Organises bits into frames, provides MAC addressing, and handles error detection/correction on the link. Sub-layers: LLC and MAC.
3. Network Layer – Handles logical addressing (IP) and selects the best routing path for packets across multiple networks.
4. Transport Layer – Ensures end-to-end reliable (or fast) delivery; performs segmentation, flow control, and error recovery (TCP = reliable, UDP = fast).
5. Session Layer – Establishes, maintains, and synchronises sessions/dialogs between two communicating systems.
6. Presentation Layer – Acts as a translator: handles data formatting, encryption/decryption, and compression.
7. Application Layer – The layer closest to the user; provides network services such as web browsing, e-mail, and file transfer.

Mnemonic (top→bottom): All People Seem To Need Data Processing.

Thus the OSI model provides a layered, standard approach that simplifies network design and ensures interoperability between different systems.

Microcomputers vs. Minicomputers vs. Mainframe Computers

Summary: A microcomputer is a small, single-user personal computer; a minicomputer is a medium, multi-user system serving a department; and a mainframe is a large, powerful machine supporting many users and handling massive transaction/data processing in big organisations like banks and government agencies.

Binary Addition: 11011 + 10110

Add bit by bit from the right (carry shown above):

  1 1 1 1     <- carries
    1 1 0 1 1
 +  1 0 1 1 0
 -----------
  1 1 0 0 0 1

Step by step (LSB to MSB):

• $1+0 = 1$, carry $0$
• $1+1 = 10$ → write $0$, carry $1$
• $0+1+1(\text{carry}) = 10$ → write $0$, carry $1$
• $1+0+1(\text{carry}) = 10$ → write $0$, carry $1$
• $1+1+1(\text{carry}) = 11$ → write $1$, carry $1$
• final carry $1$

Result: $11011_2 + 10110_2 = 110001_2$

Verification by Decimal Conversion

• $11011_2 = 16+8+0+2+1 = 27_{10}$
• $10110_2 = 16+0+4+2+0 = 22_{10}$
• Decimal sum: $27 + 22 = 49_{10}$
• Convert binary result: $110001_2 = 32+16+0+0+0+1 = 49_{10}$ ✓

Since both methods give 49, the binary addition is verified.

Embedded Operating System

An embedded operating system is a specialised, compact operating system designed to run on a dedicated embedded device that performs a specific function, rather than on a general-purpose computer. It is built into the hardware (in ROM/flash), uses limited memory and processing resources, and is optimised for reliability, real-time response, low power consumption, and a fixed set of tasks.

Key Features

• Small footprint (fits in limited memory).
• Often real-time (responds within strict time limits).
• Dedicated to one or a few specific tasks.
• High reliability and stability; usually no user upgrades.
• Resource-efficient and low power.

Examples

• Embedded Linux (routers, smart TVs)
• Windows IoT / Windows Embedded
• VxWorks, FreeRTOS, QNX (real-time systems)
• Android (mobile/embedded variant), Apple watchOS
• OS in ATMs, washing machines, microwave ovens, digital cameras, traffic light controllers, and automobiles.

Thus, an embedded OS powers everyday smart and dedicated devices where a full general-purpose OS would be unnecessary or too heavy.

Pointing Devices

A pointing device is an input device used to control the position of the cursor/pointer on the screen and to interact with graphical user interfaces by pointing, selecting, dragging, and drawing. It translates the user's physical movement into corresponding movement of the on-screen pointer.

Common Pointing Devices with Examples

1. Mouse – Hand-held device moved on a flat surface; movement and clicks control the cursor (mechanical, optical, wireless mouse).
2. Trackball – A ball mounted in a socket; the user rolls the ball with fingers to move the cursor (device stays stationary).
3. Touchpad (Trackpad) – A pressure-sensitive flat pad (common on laptops); finger movement moves the cursor.
4. Joystick – A lever that moves in all directions; widely used in gaming and flight simulators.
5. Light Pen – A pen-shaped device used to point directly at a special screen to draw or select.
6. Touch Screen – A display that detects finger/stylus touch as input (smartphones, ATMs, kiosks).
7. Stylus / Digitiser (Graphics Tablet) – Pen-like device used for drawing and precise input on tablets.

These devices make computers easier to use by allowing direct, intuitive interaction with graphical interfaces.

Memory Hierarchy of a Computer

The memory hierarchy arranges different types of computer memory in levels based on speed, cost per bit, and storage capacity. As we move up the hierarchy (toward the CPU), speed and cost increase while capacity decreases; as we move down, capacity increases while speed and cost decrease. The goal is to provide fast access at reasonable cost.

Levels (Fastest/Top → Slowest/Bottom)

1. Registers – Tiny, fastest memory inside the CPU; hold data currently being processed. (smallest size, highest cost)
2. Cache Memory (L1, L2, L3) – Very fast SRAM between CPU and main memory; stores frequently used data/instructions to reduce access time.
3. Main Memory (Primary / RAM) – Holds programs and data currently in execution; volatile, moderate speed and capacity.
4. Secondary Storage – Hard disk (HDD), SSD; large, non-volatile storage for programs and data not in immediate use. Slower than RAM.
5. Tertiary / Backup Storage – Magnetic tape, optical disks, cloud; largest capacity, lowest cost, slowest, used for archiving/backup.

Properties Across the Hierarchy

The upper levels (registers, cache, RAM) are primary memory (fast, volatile, directly accessed by CPU) and the lower levels are secondary memory (slow, non-volatile, large). This layered design gives the illusion of large, fast memory at acceptable cost.

Guided vs. Unguided Transmission Media

Guided (wired/bounded) media transmit signals along a solid physical path such as a cable, whereas unguided (wireless/unbounded) media transmit signals through air/space without a physical conductor.

Summary: Guided media (twisted pair, coaxial, fibre optic) carry signals through cables and are more secure and reliable, while unguided media (radio, microwave, infrared, satellite) transmit through the air, offering mobility but lower security.

Database Normalization

Normalization is the process of organising the data in a relational database into well-structured tables and relationships by applying a series of rules called normal forms (1NF, 2NF, 3NF, BCNF, …). It systematically decomposes large tables into smaller, related tables to reduce data redundancy and eliminate undesirable anomalies, while preserving data integrity through keys and relationships.

Why Normalization is Needed

1. Eliminate data redundancy – Avoids storing the same data repeatedly, saving storage space.
2. Remove update anomalies – Prevents inconsistency when the same data, stored in many places, is updated in only some.
3. Remove insertion anomalies – Allows data to be inserted without requiring unrelated data to be present.
4. Remove deletion anomalies – Prevents accidental loss of useful data when a record is deleted.
5. Maintain data integrity and consistency – Ensures accurate, reliable data.
6. Easier maintenance and flexible design – Simplifies modification and querying of the database.

Example (informal): Storing a student's department name in every result row is redundant; splitting into separate Student and Department tables (3NF) removes that redundancy.

Thus normalization produces a clean, efficient, and consistent database design.

Applications of Information Technology in Healthcare

Information Technology has transformed the healthcare/medical field by improving diagnosis, treatment, record-keeping, and accessibility. Major applications include:

1. Electronic Health/Medical Records (EHR/EMR) – Patient histories, prescriptions, and reports are stored digitally for quick, accurate, and shareable access among doctors.
2. Telemedicine – Remote consultation and diagnosis through video/internet, bringing healthcare to rural and distant areas.
3. Medical Imaging & Diagnosis – Computers process CT, MRI, X-ray, and ultrasound images; AI assists in detecting diseases.
4. Hospital Management Systems (HMS) – Manage appointments, billing, inventory, staff, and patient flow efficiently.
5. Health Monitoring Devices / IoT – Wearables and sensors monitor heart rate, blood pressure, and glucose, alerting doctors in real time.
6. Computer-Assisted Surgery & Robotics – Precise, minimally invasive surgeries guided by computers/robots.
7. Drug Research & Bioinformatics – Computers analyse genetic data and simulate drugs, speeding up research.
8. Online Pharmacy & Information Systems – Ordering medicines and accessing health information online.

Benefits: faster and more accurate diagnosis, better patient care, reduced errors, efficient record management, and improved access to healthcare services.

Short Note on Malware

Malware (short for malicious software) is any program or code intentionally designed to harm, damage, disrupt, or gain unauthorised access to a computer, network, or data without the user's consent. It is a major cybersecurity threat that can steal information, corrupt files, or take control of systems.

Common Types of Malware

1. Virus – Attaches itself to files/programs and spreads when the infected file is executed; corrupts data.
2. Worm – Self-replicating program that spreads across networks without needing a host file.
3. Trojan Horse – Disguises itself as legitimate software but performs malicious actions when run.
4. Spyware – Secretly collects user information and activity.
5. Ransomware – Encrypts/locks data and demands ransom for release.
6. Adware – Displays unwanted advertisements; may track behaviour.
7. Rootkit / Keylogger – Hides deep in the system or records keystrokes to steal credentials.

How Malware Spreads

Through infected e-mail attachments, malicious downloads, removable drives (USB), pirated software, and compromised websites.

Protection / Prevention

Use antivirus/anti-malware software, keep the OS and software updated, use a firewall, avoid suspicious links/attachments, and take regular backups.

Thus, malware is harmful software, and protecting systems requires both good security tools and careful user behaviour.