Chapter 2: Introduction to Computer Classification
Computers today come in various forms, from tiny devices embedded in household appliances to massive systems occupying entire rooms. They differ in size, processing power, and purpose, and are classified based on two primary criteria:
- Data Handling: Whether they process analog, digital, or both types of data.
- Functionality: The scope of tasks they can handle, ranging from general-purpose to specific-purpose applications.
Computers serve either general or specific purposes. General-purpose computers handle diverse tasks like payroll, inventory control, budgeting, or sales analysis but may lack speed for specialized tasks. Specific-purpose computers are designed for particular tasks, such as highway toll collection, airline reservations, satellite tracking, air traffic control, or industrial process control, offering high efficiency for their designated functions.
Classification According to Data-Handling Capabilities
Computers are categorized into three types based on how they process data:
Analog Computers
Analog computers process continuous data, such as electrical current, pressure, or speed, which changes smoothly rather than in discrete steps. Examples include speedometers in automobiles or voltmeters. These devices measure data first, then perform calculations in a truly parallel mode, making them fast for specific tasks. Analog computers are typically special-purpose devices.
Digital Computers
Digital computers manipulate discrete data represented by binary digits (0s and 1s), where 0 indicates the absence of an electrical signal, and 1 indicates its presence. They perform sequential operations, counting rather than measuring data, and are more accurate and faster than analog computers. Most modern computers are digital.
Hybrid Computers
Hybrid computers combine features of analog and digital computers, integrating the measurement capabilities of analog systems with the counting capabilities of digital systems. They consist of a digital unit controlling an analog unit via a hybrid interface, used for specialized applications like space vehicle simulations or astronaut training.
Classification According to Functionality
Based on performance, size, and cost, computers are classified into the following categories:
Microcomputers
Microcomputers are the smallest computers, built with microprocessors, storage, and input/output devices. Advances in very large-scale integration (VLSI) have made them compact. Examples include personal computers (PCs), categorized as:
- Desktop: Placed on a desk.
- Laptop: Portable, used on the lap.
- Personal Digital Assistants (PDAs) or Palmtops: Handheld devices.
- Mobile Computers: Smartphones or tablets.
Minicomputers
Introduced in the 1960s, minicomputers are more powerful than microcomputers, supporting business and scientific applications as multi-user systems. Early 18-bit minicomputers evolved into 32-bit "super minicomputers," which are less costly than mainframes and support 10–12 terminals.
Mainframe Computers
Mainframes are 32-bit or higher machines capable of handling complex scientific and business applications. They support over 1,000 terminals, making them suitable for large-scale operations. An example is IBM’s ES/9000 family.
Supercomputers
Supercomputers are the fastest and most expensive computers, often considered national resources. They perform billions of operations per second, used for tasks like weather forecasting, biomedical research, aircraft design, and automobile safety design. Examples include India’s PARAM (developed by C-DAC) and CRAY-3.
Embedded Computers
Embedded computers are microprocessors integrated into devices like washing machines, TVs, or air conditioners to perform specific functions. They are not as flexible as general-purpose computers and are designed to deliver predefined outputs, such as regulating temperature or setting timers.
Anatomy of a Computer
Digital computers perform five major functions:
- Inputting: Entering data into the computer using input devices.
- Storing: Holding data and instructions in main memory for processing.
- Processing: Performing arithmetic and logical operations to produce useful information.
- Outputting: Displaying results on a monitor or printing them on paper.
- Controlling: Coordinating all processes via the control unit (CU) in the CPU.
Based on these functions, computer hardware is divided into:
- Central Processing Unit (CPU): The brain of the computer, responsible for calculations, manipulations, and controlling other units.
- Peripheral Devices: Input/output and storage devices connected to the CPU.
Central Processing Unit (CPU)
The CPU, often called the brain of the computer, handles major calculations, comparisons, and operations. Its main components are:
- Arithmetic and Logic Unit (ALU): Performs calculations (e.g., addition, subtraction) and logical operations (e.g., comparisons). Data and instructions are transferred from memory to the ALU for processing.
- Control Unit (CU): Directs operations by selecting and interpreting program instructions, ensuring coordination among input, output, and processing units. It acts as the central nervous system without processing data itself.
- Memory Unit (Registers): Temporary internal memory within the CPU, storing data in binary during processing.
Classification by Generations
Computers are also classified by technological advancements, known as generations:
- First Generation (1940s–1950s): Used vacuum tubes, large, and consumed high power (e.g., ENIAC).
- Second Generation (1950s–1960s): Used transistors, smaller and more reliable.
- Third Generation (1960s–1970s): Introduced integrated circuits, increasing speed and efficiency.
- Fourth Generation (1970s–present): Utilized microprocessors, leading to personal computers and widespread use.
- Fifth Generation (present–future): Focuses on artificial intelligence, quantum computing, and parallel processing.
This classification highlights the evolution of computer technology, complementing classifications by data handling and functionality.
Unit Questions
- How many types of computers?
- How many types of computers are on the basis of data handling?
- How many types of computers are on the basis of functionality?
- How many types of computers are on the basis of generations?
- How many types of computers are on the basis of purpose?
- What is an analog computer?
- What is a digital computer?
- What is a hybrid computer?
- What is a microcomputer?
- What is a minicomputer?
- What is a mainframe computer?
- What is a supercomputer?
- What is an embedded computer?
- What is the anatomy of a computer?
- What is a CPU?
- What is the full form of CPU?
- What is the Central Processing Unit?
- What is an ALU?
- What is the full form of ALU?
- What is the Arithmetic and Logic Unit?
- What is a CU?
- What is the full form of CU?
- What is the Control Unit?
- What is the MU?
- What is the full form of MU?
- What is the Memory Unit?
- What are registers (MU)?
- What is the full form of registers (MU)?