ICS (Intermediate in Computer Science) Computer Science (Part I) Syllabus

What is RAM, and is it volatile or non-volatile?

Random Access Memory — the main working memory that temporarily holds data and programs in use. It is volatile (contents are lost when power is off).

What is ROM, and is it volatile or non-volatile?

Read Only Memory — non-volatile memory that stores permanent instructions (like the BIOS/bootstrap) which cannot normally be changed; contents are retained without power.

Differentiate between SRAM and DRAM.

SRAM (Static RAM) uses flip-flops, is faster and more expensive, and does not need refreshing (used in cache). DRAM (Dynamic RAM) uses capacitors, is slower and cheaper, and must be refreshed continuously (used as main memory).

What are PROM, EPROM, and EEPROM?

PROM: Programmable ROM (written once by user). EPROM: Erasable PROM (erased by ultraviolet light). EEPROM: Electrically Erasable PROM (erased and rewritten using electrical signals).

What is cache memory and why is it used?

A small, very fast memory between the CPU and main memory that stores frequently used data and instructions to speed up processing by reducing access time.

What is the difference between volatile and non-volatile memory?

Volatile memory loses its contents when power is switched off (e.g., RAM); non-volatile memory retains its contents without power (e.g., ROM, hard disk, flash memory).

List the units of memory measurement from smallest to largest (bit to terabyte).

Bit, Nibble (4 bits), Byte (8 bits), Kilobyte (KB), Megabyte (MB), Gigabyte (GB), Terabyte (TB), each successive (KB onward) being 1024 of the previous.

How many bits are in a byte, and how many bytes in a kilobyte?

1 byte = 8 bits; 1 kilobyte (KB) = 1024 bytes (2^10 bytes).

What is the difference between magnetic, optical, and solid-state storage? Give an example of each.

Magnetic uses magnetized surfaces (e.g., hard disk); optical uses laser light to read/write (e.g., CD/DVD); solid-state uses flash memory chips with no moving parts (e.g., USB flash drive, SSD).

Compare CD, DVD, and Blu-ray storage capacities.

A CD holds about 700 MB, a single-layer DVD about 4.7 GB, and a single-layer Blu-ray disc about 25 GB.

What is the basis for classifying computers by purpose, and name the two types?

By purpose: general-purpose computers (perform many varied tasks, e.g., PCs) and special-purpose computers (designed for one specific task, e.g., ATM, traffic control).

What are the three types of computers based on data handling (operation)?

Analog computers (measure continuous physical data), digital computers (process discrete data as 0s and 1s), and hybrid computers (combine both analog and digital features).

Where are hybrid computers commonly used?

In applications needing both measurement and computation, such as hospital ICU monitoring machines and weather/petrol-pump systems.

List the four classes of computers by size and capacity, largest to smallest.

Supercomputer, mainframe computer, minicomputer, and microcomputer (personal computer).

What is a supercomputer and where is it used?

The fastest and most powerful type of computer, used for highly complex calculations such as weather forecasting, nuclear research, and scientific simulations.

What is a mainframe computer used for?

A large, powerful computer that supports many users simultaneously, used by big organizations (banks, airlines, governments) for processing huge volumes of data.

What is a computer network?

A collection of two or more computers and devices connected together to share data, resources (printers, files), and communicate with one another.

What are the main advantages of a computer network?

Resource sharing (hardware/software), data/file sharing, communication, centralized data management, and cost reduction.

Define LAN, MAN, and WAN by their coverage area.

LAN (Local Area Network): covers a small area like a building/campus. MAN (Metropolitan Area Network): covers a city. WAN (Wide Area Network): covers large areas like countries/continents (the Internet is the largest WAN).

What is network topology?

The physical or logical arrangement (layout) of computers, devices, and cables in a network.

Describe bus topology and one disadvantage.

All computers connect to a single central cable (backbone). Disadvantage: if the main cable fails, the whole network goes down, and performance drops with heavy traffic.

Describe star topology and one advantage.

All computers connect to a central device (hub/switch). Advantage: failure of one cable/node does not affect others, and it is easy to add/remove nodes; but if the hub fails, the whole network fails.

Describe ring topology.

Each computer connects to two neighbors forming a closed loop; data travels in one direction around the ring, passing through each node until it reaches its destination.

Describe mesh topology and its main advantage.

Every device is connected to every other device by dedicated links. Advantage: highly reliable/fault-tolerant since failure of one link does not break the network, but it requires many cables and is costly.

What is the Internet?

A global network of interconnected computer networks that allows worldwide communication and information sharing using standard protocols (TCP/IP).

What is the difference between the Internet and the World Wide Web (WWW)?

The Internet is the global physical network of connected computers; the WWW is a service running on the Internet — a system of interlinked web pages/documents accessed via browsers using HTTP.

What is the function of a modem?

A modem (modulator-demodulator) converts digital signals from a computer into analog signals for transmission over telephone lines (modulation) and converts incoming analog signals back to digital (demodulation).

What is the difference between a hub and a switch?

A hub broadcasts incoming data to all connected ports (less efficient); a switch sends data only to the specific destination port using MAC addresses (more efficient and secure).

What does a router do?

A router connects two or more different networks and forwards (routes) data packets between them along the best path, e.g., connecting a home/LAN to the Internet.

What are the five basic components of a communication system?

Sender (source), message (data), medium (transmission channel), receiver (destination), and protocol (set of rules); an encoder/decoder may also be included.

What is the difference between guided and unguided transmission media? Give examples.

Guided (wired) media transmit signals along a physical path — twisted pair, coaxial cable, fiber optic. Unguided (wireless) media transmit signals through air/space — radio waves, microwaves, infrared, satellite.

Compare the three main types of guided media (twisted pair, coaxial, fiber optic).

Twisted pair: cheapest, low bandwidth, used in telephones/LANs. Coaxial: higher bandwidth, used in cable TV. Fiber optic: uses light, fastest with very high bandwidth, immune to interference, but most expensive.

What are the three communication (data transmission) modes? Give an example of each.

Simplex (one direction only, e.g., radio/TV broadcast), Half-duplex (both directions but one at a time, e.g., walkie-talkie), and Full-duplex (both directions simultaneously, e.g., telephone call).