The History of Computers
Computers have wedged themselves into every facet of our lives—they are what we would use
as the symbolic representation of the modern world.
But did you know that the history of computers dates back to the 1800s?
Indeed, the history and evolution of computers is quite extraordinary—and with many early
computing technology innovations tied to defense contracts, much of this information were kept
secret from the public for decades. In this article, we explore the development and progression of
computers.
Mid-1800s-1930s: Early Mechanical Computers
The first computers were designed by Charles Babbage in the mid-1800s, and are sometimes
collectively known as the Babbage Engines. These include the Difference Engine No. 1, the
Analytical Engine, and the Difference Engine No. 2.
The
Difference Engine was constructed from designs by Charles Babbage. Photo by Allan J. Cronin
These early computers were never completed during Babbage’s lifetime, but their complete
designs were preserved. Eventually, one was built in 2002.
While these early mechanical computers bore little resemblance to the computers in use today,
they paved the way for a number of technologies that are used by modern computers, or were
instrumental in their development. These concepts include of the idea of separating storage from
processing, the logical structure of computers, and the way that data and instructions are inputted
and outputted.
Z1 was used to take the U.S. Census in 1890.
Other important mechanical computers are the Automatic Electrical Tabulating Machine—which
was used in the U.S. Census of 1890 to handle data from more than 62 million Americans—and
the first binary computer: Konrad Zuse’s Z1, which was developed in 1938 and was the
precursor to the first electro-mechanical computer.
1930s: Electro-Mechanical Computers
Electro-mechanical computers generally worked with relays and/or vacuum tubes, which could
be used as switches.
Some electro-mechanical computers—such as the Differential Analyzer built in 1930—used
purely mechanical internals but employed electric motors to power them.
These early electro-mechanical computers were either analog or were digital—such as the Model
K and the Complex Number Calculator, both produced by George Stibitz.
Stibitz, by the way, was also responsible for the first remote access computing, done at a
conference at Dartmouth College in New Hampshire. He took a teleprinter to the conference,
leaving his computer in New York City, and then proceeded to take problems posed by the
audience. He then entered the problems on the keypad of his teleprinter, which outputted the
answers afterward.
Z3 used floating-point numbers which improved the accuracy of calculations.
It was during the development of these early electro-mechanical computers that many of the
technologies and concepts still used today were first developed. The Z3, a descendent of the Z1
developed by Konrad Zuse, was one such pioneering computer. The Z3 used floating-point
numbers in computations and was the first program-controlled digital computer.
Other electro-mechanical computers included Bombes, which were used during WWII to
decrypt German codes.
1940s: Electronic Computers
Colossus—whose name was fitting for its size—was developed during World War II.
The first electronic computers were developed during the World War II, with the earliest of those
being the Colossus. The Colossus was developed to decrypt secret German codes during the war.
It used vacuum tubes and paper tape and could perform a number of Boolean (e.g. true/false,
yes/no) logical operations.
Williams Tube used RAM for its computations.
Another notable early electronic computer was nicknamed "The Baby" (officially known as the
Manchester Small-Scale Experimental Machine). While the computer itself wasn’t remarkable—
it was the first computer to use the Williams Tube, a type of random access memory (RAM)
that used a cathode-ray tube.
Some early electronic computers used decimal numeric systems (such as the ENIAC and the
Harvard Mark 1), while others—like the Atanasoff-Berry Computer and the Colossus Mark 2—
used binary systems. With the exception of the Atanasoff-Berry Computer, all the major models
were programmable, either using punch cards, patch cables and switches, or through stored
programs in memory.
1950s: The First Commercial Computers
The first commercially available computers came in the 1950s. While computing up until this
time had mainly focused on scientific, mathematical, and defense capabilities, new computers
were designed for business functions, such as banking and accounting.
The J. Lyons Company, which was a British catering firm, invested heavily in some of these
early computers. In 1951, LEO (Lyons Electronic Office) became the first computer to run a
regular routine office job. By November of that year, they were using the LEO to run a weekly
bakery valuations job.
The
UNIVAC was the first mass-produced computer.
The UNIVAC was the first commercial computer developed in the U.S., with its first unit
delivered to the U.S. Census Bureau. It was the first mass-produced computer, with more than
45 units eventually produced and sold.
The IBM 701 was another notable development in early commercial computing; it was the first
mainframe computer produced by IBM. It was around the same time that the Fortran
programming language was being developed (for the 704).
The IBM 650 would cost you $4 million dollars if you bought it today.
A smaller IBM 650 was developed in the mid-1950s, and was popular due to its smaller size and
footprint (it still weighed over 900kg, with a separate 1350kg power supply).
They cost the equivalent of almost $4 million today (adjusted for inflation).
Mid-1950s: Transistor Computers
The development of transistors led to the replacement of vacuum tubes, and resulted in
significantly smaller computers. In the beginning, they were less reliable than the vacuum tubes
they replaced, but they also consumed significantly less power.
IBM 350 RAMAC used disk drives.
These transistors also led to developments in computer peripherals. The first disk drive, the
IBM 350 RAMAC, was the first of these introduced in 1956. Remote terminals also became
more common with these second-generation computers.
1960s: The Microchip and the Microprocessor
The microchip (or integrated circuit) is one of the most important advances in computing
technology. Many overlaps in history existed between microchip-based computers and transistorbased computers throughout the 1960s, and even into the early 1970s.
Micochips allowed the manufacturing of smaller computers. Photo by Ioan Sameli
The microchip spurred the production of minicomputers and microcomputers, which were small
and inexpensive enough for small businesses and even individuals to own. The microchip also
led to the microprocessor, another breakthrough technology that was important in the
development of the personal computer.
There were three microprocessor designs that came out at about the same time. The first was
produced by Intel (the 4004). Soon after, models from Texas Instruments (the TMS 1000) and
Garret AiResearch (the Central Air Data Computer, or CADC) followed.
The first processors were 4-bit, but 8-bit models quickly followed by 1972.
16-bit models were produced in 1973, and 32-bit models soon followed. AT&T Bell Labs
created the first fully 32-bit single-chip microprocessor, which used 32-bit buses, 32-bit data
paths, and 32-bit addresses, in 1980.
The first 64-bit microprocessors were in use in the early 1990s in some markets, though they
didn’t appear in the PC market until the early 2000s.
1970s: Personal Computers
The first personal computers were built in the early 1970s. Most of these were limitedproduction runs, and worked based on small-scale integrated circuits and multi-chip CPUs.
The Commodore PET was a personal computer in the 70s. Photo by Tomislav Medak
The Altair 8800 was the first popular computer using a single-chip microprocessor. It was also
sold in kit form to electronics hobbyists, meaning purchasers had to assemble their own
computers.
Clones of this machine quickly cropped up, and soon there was an entire market based on the
design and architecture of the 8800. It also spawned a club based around hobbyist computer
builders, the Homebrew Computer Club.
1977 saw the rise of the "Trinity" (based on a reference in Byte magazine): the Commodore
PET, the Apple II, and the Tandy Corporation’s TRS-80. These three computer models
eventually went on to sell millions.
These early PCs had between 4kB and 48kB of RAM. The Apple II was the only one with a fullcolor, graphics-capable display, and eventually became the best-seller among the trinity, with
more than 4 million units sold.
1980s-1990s: The Early Notebooks and Laptops
One particularly notable development in the 1980s was the advent of the commercially available
portable computer.
Osborne 1 was small and portable enough to transport. Photo by Tomislav Medak
The first of these was the Osborne 1, in 1981. It had a tiny 5" monitor and was large and heavy
compared to modern laptops (weighing in at 23.5 pounds). Portable computers continued to
develop, though, and eventually became streamlined and easily portable, as the notebooks we
have today are.
These early portable computers were portable only in the most technical sense of the word.
Generally, they were anywhere from the size of a large electric typewriter to the size of a
suitcase.
The Gavilan SC was the first PC to be sold as a "laptop".
The first laptop with a flip form factor, was produced in 1982, but the first portable computer
that was actually marketed as a "laptop" was the Gavilan SC in 1983.
Early models had monochrome displays, though there were color displays available starting in
1984 (the Commodore SX-64).
Laptops grew in popularity as they became smaller and lighter. By 1988, displays had reached
VGA resolution, and by 1993 they had 256-color screens. From there, resolutions and colors
progressed quickly. Other hardware features added during the 1990s and early 2000s included
high-capacity hard drives and optical drives.
Laptops typically come in three categories, as shown by these Macbooks. Photo by Benjamin
Nagel
Laptops are generally broken down into a three different categories:



Desktop replacements
Standard notebooks
Subnotebooks
Desktop replacements are usually larger, with displays of 15-17" and performance comparable
with some better desktop computers.
Standard notebooks usually have displays of 13-15" and are a good compromise between
performance and portability.
Subnotebooks, including netbooks, have displays smaller than 13" and fewer features than
standard notebooks.
2000s: The Rise of Mobile Computing
Mobile computing is one of the most recent major milestones in the history of computers.
Many smartphones today have higher processor speeds and more memory than desktop PCs had
even ten years ago. With phones like the iPhone and the Motorola Droid, it’s becoming possible
to perform most of the functions once reserved for desktop PCs from anywhere.
The Droid is a smartphone capable of basic computing tasks such as emailing and web
browsing.
Mobile computing really got its start in the 1980s, with the pocket PCs of the era. These were
something like a cross between a calculator, a small home computer and a PDA. They largely
fell out of favor by the 1990s. During the 1990s, PDAs (Personal Digital Assistant) became
popular.
A number of manufacturers had models, including Apple and Palm. The main feature PDAs had
that not all pocket PCs had was a touchscreen interface. PDAs are still manufactured and used
today, though they’ve largely been replaced by smartphones.
Smartphones have truly revolutionized mobile computing. Most basic computing functions can
now be done on a smartphone, such as email, browsing the internet, and uploading photos and
videos.
Late 2000s: Netbooks
Another recent progression in computing history is the development of netbook computers.
Netbooks are smaller and more portable than standard laptops, while still being capable of
performing most functions average computer users need (using the Internet, managing email, and
using basic office programs). Some netbooks go as far as to have not only built-in WiFi
capabilities, but also built-in mobile broadband connectivity options.
The Asus Eee PC 700 was the first netbook to enter mass production.
The first mass-produced netbook was the Asus Eee PC 700, released in 2007. They were
originally released in Asia, but were released in the US not long afterward.
Other manufacturers quickly followed suit, releasing additional models throughout 2008 and
2009.
One of the main advantages of netbooks is their lower cost (generally ranging from around
US$200-$600). Some mobile broadband providers have even offered netbooks for free with an
extended service contract. Comcast also had a promotion in 2009 that offered a free netbook
when you signed up for their cable internet services.
Most netbooks now come with Windows or Linux installed, and soon, there will be Androidbased netbooks available from Asus and other manufacturers.
The history of computing spans nearly two centuries at this point, much longer than most people
realize. From the mechanical computers of the 1800s to the room-sized mainframes of the mid20th century, all the way up to the netbooks and smartphones of today, computers have evolved
radically throughout their history.
The past 100 years have brought technological leaps and bounds to computing, and there’s no
telling what the next 100 years might bring.