Computer:
- The word computer comes from the word “compute”, which means to, “calculate".
- Thereby, a computer is an electronic device that can perform arithmetic operations at high speed.
- A computer is also called a data processor because it can store, process, and retrieve data whenever desired.
- Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (programs) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.
Data Processing:
- The activity of processing data using a computer is called data processing.
- Data > Capture Data > Manipulate Data > Output Results > Information
- Data is the raw material used as input and information is the processed data obtained as output of data processing.
Basic Definitions:
Some basic definitions related to subject matter are: -
1. Hardware – the basic physical components that constitute a computer are collectively called ‘Hardware’. Computer hardware includes input and output units, storage units, central processing units and other peripherals.
2. Software – software means a set of programs, which are used in the computer. A program is a set of logical instructions that is required to accomplish a particular task.
3. Input Devices – the devices which are used to enter/input data and programs in a computer are known as input devices. These devices convert what we input into a form that is understandable by the computer.
4. Output Devices – the devices which convert processed data into a form understandable by humans in various formats viz., hardcopy, audio, video, etc. are called output devices.
5. Memory – the memory of a computer is the place where data and instructions are stored.
6. Primary Memory - Primary memory (main memory) is volatile, volatile storage that is fast, expensive, and used by the CPU for active data and program execution (e.g., RAM, cache).
7. RAM (Random Access Memory): it is the fast, temporary, and volatile "short-term memory" of a computer or electronic device, storing active data and program instructions for the processor to access quickly. It loses its data when power is lost, requiring programs and data to be reloaded from slower storage like an SSD or HDD upon startup. RAM's high speed allows for faster performance and smoother multitasking, but its volatility and higher cost make it unsuitable for long-term storage.
Types of RAM include: SRAM (Static RAM) and DRAM (Dynamic RAM).
8. ROM (Read Only Memory): it is a non-volatile memory that stores permanent data and instructions, essential for a device's startup and basic functions, as its contents are retained even when power is off and cannot be easily modified or erased. Examples include the firmware for devices like printers, game consoles, and the BIOS (Basic Input/output System) in computers, which contains the basic programs needed to boot the system.
Types of ROM include: MROM (Mask ROM), PROM (Programmable ROM), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and Flash Memory.
9. Secondary Memory - secondary memory (storage) is non-volatile, slower, less expensive, and used for long-term storage of files and programs even when the computer is off (e.g., SSDs, HDDs).
10. System Software - System software is a set of computer programs designed to run and manage the computer's hardware and application software, acting as an intermediary between the two. It controls the computer's basic functions and provides a platform for user-facing application programs to run on. Key components of system software include the operating system (OS) (e.g., Windows, macOS, Android), device drivers (software programs that act as translators, enabling communication between your computer's operating system and its hardware components), and utility software (a type of software that helps manage, maintain, and optimize a computer system, performing specific tasks to improve its performance, security, and functionality).
11. Application Software - a computer program designed for end-users to perform specific tasks, such as writing documents, browsing the internet, or playing games, rather than managing the computer's internal functions. Examples include word processors (like Microsoft Word), web browsers (like Google Chrome), and mobile apps (like WhatsApp), which help users be productive, creative, and connected.
12. Firmware - a low-level software permanently embedded into a hardware device's non-volatile memory, providing the basic instructions that allow the hardware to function and communicate with other software. It acts as a direct link between the computer's physical components and the operating system, performing essential tasks like startup, hardware initialization, and input/output operations. Examples include the BIOS and UEFI found in PCs, which are crucial for booting the system.
13. Arithmetic Logic Unit (ALU) – it is the place where the actual executions of instructions take place during processing operation. The unit performs mathematical functions such as addition, subtraction, multiplication and various logical functions. ALU also determine the speed of data processing.
14. Control Unit (CU) - Control Unit of a computer system manages and coordinates the operations of all other components of the computer system.
15. Microprocessors - A microprocessor in a computer is the brain or central processing unit (CPU), a single integrated circuit (chip) that performs arithmetic, logic, and control operations to execute program instructions. Microprocessors consists of registers, transistors, capacitors etc.
Characteristics of Computer:
Characteristics of a computer are as follows: -
1. Automatic – given a job, computer can work on it automatically without human intervention.
2. Speed – computer can work very fast. It takes only few seconds to perform complex tasks. It can perform millions of functions per second.
3. Accuracy – the degree of accuracy of a computer is very high and every calculation is performed with the same accuracy. The errors in the computer are due to humans or inaccurate/incorrect data/input.
4. Versatility – it means to do or the capacity to perform different tasks simultaneously. We may use it to play music, and at the same time also book online tickets.
5. Storage – the computer has an in-built memory where it can store a large amount of data. We can also store data in secondary storage devices such as floppy disc, in drive, CD etc.
6. Diligence – Computer is free from monotony, tiredness, and lack of concentration. It can continuously work for hours without creating any error and without grumbling.
7. Power of Remembering - Computer can store and recall any amount of information because of its secondary storage capability. It forgets or loses certain information only when it is asked to do so.
8. NO I.Q. - A computer does only what it is programmed to do. It cannot take its own decision in this regard.
9. No Feelings - Computers are devoid of emotions. Their judgement is based on the instructions given to them in the form of programs that are written by us (human beings).
10. Reliability - Computers are designed to perform consistently and dependably, reducing human error in critical tasks.
Basic Operations:
Basic operations of a computer are as follows: -
1. Input - The process of entering data and instructions into the computer system. The computer takes in data or instructions from various input devices such as mouse, keyboard etc.
2. Processing - Performing arithmetic operations (add, subtract, multiply, divide, etc.) or logical operations (comparisons like equal to, less than, greater than, etc.) on data to convert them into useful information. The Central Processing Unit (CPU) performs calculations and executes instructions to process the input data.
3. Storage - Saving data and instructions to make them readily available for initial or additional processing whenever required. Data and programs are stored in various types of memory including RAM (Random Access Memory) for temporary storage and hard drives or SSDs (Solid State Drives) for long term storage.
4. Output - The process of producing useful information or results for the user such as a printed report or visual display. The computer displays results as info through output devices like monitors, speakers or printers.
5. Control - Directing the manner and sequence in which all of the above operations are performed. The CPU manages and controls the execution of instructions and data flow within the computer.
These operations are fundamental functions that enable a computer to program tasks and process information.
