Computers have seamlessly integrated into every aspect of our daily lives, serving as a quintessential symbol of the modern era.However, did you know that the timeline of computer development extends back to the 19th century?Undoubtedly, the journey and progression of computers is a remarkable story—often shrouded in secrecy due to early innovations linked to defense contracts. This article delves into the evolution of computing technology.Charles Babbage, in the mid-1800s, conceptualized the first computers, colloquially known as the Babbage Engines, which encompassed the Difference Engine No. 1, the Analytical Engine, and the Difference Engine No. 2. 
CroninDespite not being completed during Babbage’s lifetime, the detailed plans were preserved, and one was reconstructed in 2002.These pioneering mechanical computers, while vastly different from today’s computers, laid the groundwork for numerous technologies that are integral to modern computing. These include the concept of separating storage and processing, the logical architecture of computers, and the methods of data and instruction input and output. 
Other pivotal mechanical computers include the Automatic Electrical Tabulating Machine, instrumental in the 1890 U.S. Census, and Konrad Zuse’s Z1, the first binary computer, developed in 1938 and a precursor to the first electro-mechanical computer.Electro-mechanical computers typically utilized relays and/or vacuum tubes for switching.Some early electro-mechanical computers, like the Differential Analyzer built in 1930, employed purely mechanical components but were powered by electric motors.These early electro-mechanical computers were either analog or digital, such as the Model K and the Complex Number Calculator, both created by George Stibitz.Incidentally, Stibitz was also behind the first remote access computing, which occurred at Dartmouth College in New Hampshire. He transported a teleprinter to the conference, leaving his computer in New York City, and then resolved audience-proposed problems remotely. 
The development of these early electro-mechanical computers marked the birth of many technologies and concepts still in use today. The Z3, a descendant of the Z1 by Konrad Zuse, was a trailblazing computer.The Z3 employed floating-point numbers in calculations and was the first program-controlled digital computer.Other electro-mechanical computers included Bombes, which were utilized during World War II to decipher German codes. 
The first electronic computers emerged during World War II, with the Colossus being the earliest. Designed to decrypt secret German codes, the Colossus utilized vacuum tubes and paper tape and performed various Boolean logical operations. 
Another significant early electronic computer was the “Baby” (officially the Manchester Small-Scale Experimental Machine), which was the first to use the Williams Tube, a form of random access memory (RAM) based on a cathode-ray tube.Some early electronic computers employed decimal numeric systems (like the ENIAC and the Harvard Mark 1), while others, like the Atanasoff-Berry Computer and the Colossus Mark 2, used binary systems.Except for the Atanasoff-Berry Computer, all major models were programmable, either through punch cards, patch cables and switches, or via stored programs in memory.The first commercially available computers were introduced in the 1950s. Until then, computing had focused primarily on scientific, mathematical, and defense applications. The new computers were designed for business tasks such as banking and accounting.The J. Lyons Company, a British catering firm, was a significant investor in these early computers.In 1951, LEO (Lyons Electronic Office) became the first computer to handle a regular office job, running a weekly bakery valuation task by November of that year. 
The UNIVAC was the first commercial computer developed in the U.S., delivered to the U.S. Census Bureau. It was the first mass-produced computer, with over 45 units produced and sold.The IBM 701 was another significant development in early commercial computing; it was the first mainframe computer produced by IBM. Concurrently, the Fortran programming language was being developed for the 704 model. 
A smaller IBM 650 was developed in the mid-1950s and gained popularity due to its compact size and footprint, though it still weighed over 900kg with a separate 1350kg power supply. Today, this would equate to nearly $4 million when adjusted for inflation.The advent of transistors replaced vacuum tubes, leading to significantly smaller computers. Initially, transistors were less reliable than vacuum tubes but consumed much less power. 
These transistors also spurred advancements in computer peripherals.The first disk drive, the IBM 350 RAMAC, was introduced in 1956, followed by the rise of remote terminals with these second-generation computers.The microchip, or integrated circuit, represents one of the most significant advancements in computing technology. Throughout the 1960s and into the early 1970s, there were numerous overlaps in history between microchip-based computers and transistor-based computers. 
The microchip propelled the production of minicomputers and microcomputers, which were small and affordable enough for small businesses and individuals. The microchip also led to the microprocessor, a breakthrough technology crucial in the development of the personal computer.Three microprocessor designs emerged concurrently: Intel’s 4004, followed by Texas Instruments’ TMS 1000 and Garret AiResearch’s Central Air Data Computer (CADC). 
The initial processors were 4-bit, but 8-bit models followed in 1972, with 16-bit models produced in 1973 and 32-bit models soon after.AT&T Bell Labs created the first fully 32-bit single-chip microprocessor in 1980, featuring 32-bit buses, data paths, and addresses. The first 64-bit microprocessors were in use in some markets by the early 1990s, though they didn’t appear in the PC market until the early 2000s.The first personal computers were developed in the early 1970s, mostly limited-production runs based on small-scale integrated circuits and multi-chip CPUs. 
The Altair 8800 was the first popular computer using a single-chip microprocessor and was also sold as a kit to electronics hobbyists, requiring assembly by the buyer. Clones of this machine soon became prevalent, and an entire market based on the 8800’s design and architecture emerged. It also gave rise to the Homebrew Computer Club for hobbyist computer builders.1977 saw the rise of the “Trinity” (as referenced in Byte magazine): the Commodore PET, the Apple II, and Tandy Corporation’s TRS-80. These models eventually sold millions. Early PCs had between 4kB and 48kB of RAM, with the Apple II being the only one with a full-color, graphics-capable display and becoming the best-seller among the Trinity, with over 4 million units sold.A significant development in the 1980s was the introduction of commercially available portable computers. 
The first of these was the Osborne 1, in 1981, featuring a tiny 5″ monitor and being large and heavy compared to modern laptops (weighing 23.5 pounds). Despite this, portable computers continued to evolve, eventually becoming streamlined and easily portable, much like the notebooks we use today.These early portable computers were technically portable, but only in the most technical sense. They were generally the size of a large electric typewriter to a suitcase. 
The first laptop with a flip form factor was produced in 1982, but the first portable computer marketed as a “laptop” was the Gavilan SC in 1983. Early models had monochrome displays, with color displays becoming available in 1984 (the Commodore SX-64). As laptops became smaller and lighter, their popularity grew. By 1988, displays reached VGA resolution, and by 1993, they had 256-color screens. Resolutions and colors progressed rapidly from there.Additional hardware features added during the 1990s and early 2000s included high-capacity hard drives and optical drives.Laptops are generally categorized into three different types:
Desktop replacements
Standard notebooks
Subnotebooks
Desktop replacements are usually larger, with displays of 15-17″, and performance comparable to some high-end desktop computers. Standard notebooks have displays of 13-15″ and offer a good balance between performance and portability. Subnotebooks, including netbooks, have smaller displays than 13″ and fewer features than standard notebooks.Mobile computing is one of the most recent major milestones in computer history.Many smartphones today have processor speeds and memory greater than desktop PCs had even a decade ago. With devices like the iPhone and the Motorola Droid, it’s now possible to perform most functions once exclusive to desktop PCs from anywhere. 
Mobile computing actually began in the 1980s with the pocket PCs of the era, which were a blend of a calculator, a small home computer, and a PDA. They lost popularity by the 1990s. During the 1990s, PDAs (Personal Digital Assistants) gained popularity.A variety of manufacturers produced models, including Apple and Palm. PDAs had a touchscreen interface, a feature not all pocket PCs possessed. PDAs are still manufactured and used
