Introduction to computers:

Introduction to Computers

Early Computing

Computing began with the invention of the abacus, a counting tool that dates back to ancient civilizations such as the Greeks and Romans. These early counting devices were replaced by mechanical calculators in the 17th century, like the Pascaline, developed by Blaise Pascal. In the 19th century, Charles Xavier Thomas and Paul Crayence created the first programmable electronic calculator, the Analytical Engine.

Vacuum Tubes and Logic Gates

In the early 20th century, vacuum tubes replaced mechanical relays and became the primary component for computing devices. Vacuum tubes were small glass tubes that amplified and acted as switches, facilitating the flow of electrons. However, they were large, power-hungry, and prone to failure, leading to the development of transistors in the late 1940s.

Transistors and the Birth of the CPU

Transistors revolutionized computing by allowing for smaller, more efficient, and more reliable electronic devices. In 1945, John von Neumann proposed the concept of an Arithmetic Logic Unit (ALU), which is an integral part of the CPU, even in simple processors. The ALU performs arithmetic operations and logical operations on data stored in the computer's memory.

Word Size and Cache

Modern processors use different word sizes to process data. Initially, PC processors had word sizes of 16 bits, later increasing to 32 bits, and now 64 bits. Word size determines how quickly data can be transferred within each microprocessor. To further improve performance, cache memory was developed. Level 2 cache is external cache that has more memory, ranging from 64 kB to 2 MB. Level 3 cache is also external but is only used in high-end computers. Processors with higher cache sizes are faster but also more expensive.

Moore's Law and Future of Computing

Moore's Law, named after Gordon Moore, predicts the number of transistors on a microchip will double approximately every two years. This rate of progress has held true since the mid-20th century, but it has slowed somewhat in recent years. Despite this, advancements in computing continue, driven by the need for more efficient processors and smaller, cheaper devices.