The Most Impactful Computing Inventions

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In the last 40 years, computers have evolved from enormous and complex machines requiring specialized knowledge for operating, to small devices that most people can understand and operate in a few hours. Here are some software developments that have been revolutionary in the history of computing.


CP/M was something of an accidental invention. Gary Kidall was working at Naval Research labs on an operating system and wanted to continue work at home on his own home-built computer, but the machine at work was too different. So he separated out the machine-dependent parts of the operating system (the disk controller and serial input/output) into a small subsection (the BIOS), the bulk of the operating system left unchanged. This concept made it simpler to “port” – the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed. Having a single operating system made it possible for applications such as Wordstar to flourish.


In the early days of small computers, programs were written using text editors, and then the program files were processed through compilers and linkers to produce a finished program. EMACS was (and is) an editing system for the UNIX operating system and provided the first programming environment. The compiler and linker was still there, but the process was hidden. Essentially the programmer always worked in EMACS; the program was edited, a single keypress would compile and link it. EMACS can be configured to “know” about the format of different languages, keywords are shown in different colors, function parameters are shown automatically – it’s changed how programmers program. Virtually all programming languages provide an environment now. But it started with EMACS. Emacs is one of the two main contenders in the traditional editor wars, the other being vi [which is much better! -jfrater].



Picture 5-6UNIX shows the advantage of giving bright guys some time and money. Ken Thompson was the bright guy and he, essentially, developed the first version of UNIX (then called Unics) to make a game run faster. UNIX had the advantage of CP/M that it could fairly easily be ported to different machines, but it wasn’t particularly dependent on the hardware – CP/M needed a 8080/Z80 processor, UNIX can generally be run on anything from a phone to a supercomputer. This is because UNIX was essentially written in a high level language (of which, more below). UNIX (and its modern derivative Linux) is a programmers dream – it doesn’t get in the way too much, has powerful editors, good compilers, is very adaptable and, probably most importantly, a world-wide community of fans and users. Apple’s Mac OS X is based on UNIX (BSD to be exact), and most developments in modern computing (virtual desktops, virtual memory spring to mind) start on UNIX. Pictured above is the terminal on my Mac OS X machine which gives you access to the underlying UNIX system.

C Programming Language

Simu-Double2TypeC is the language of UNIX, C was written by Dennis Ritchie in 1972. Pretty much the whole of UNIX and applications that run on UNIX are written in C, or C derived languages (C# or C++). C is a small language and therefore easily learnt and easily ported to different operating systems – C compilers are usually written in C. Some of the key features of C include extendibility, close coupling with the hardware, fairly strong variable typing and function pointers. These don’t mean much unless you’re a programmer! But essentially, they stop the language getting in the way of what the programmer is trying to achieve. The influence of C has spread with the influence of UNIX; most applications throughout Windows/Linux/Mac OS are written in C, C++ or C#. C has also influenced other computer languages; Visual Basic now looks very like C.


Smalltalk was the first successful object orientated language. Before Smalltalk, languages dealt largely with strings and numbers. Smalltalk allowed the programmer to describe all kinds of things – shapes, sounds, video – as objects. Imagine writing a drawing program before objects; if you want to draw a circle on the screen, you use a function for drawing circles. If you want to draw a square, you use a different function to draw a square. And so on for all the shapes. With object orientated languages, you can use a single function to draw a shape – and tell it it’s a square, circle and so on. It made application writing much easier. Smalltalk isn’t used much nowadays; C++, C#, Visual Basic are far more common, but they are all object orientated. A side effect of object orientation is that the executable applications became much bigger; it was with the introduction of objects, particularly C++, that applications started being delivered on multiple CDs.

Xerox Alto Operating System

The single most influential operating system, bar none. Are you using a graphical user interface (Windows, Mac OS X) and a mouse? Are you connected to a network? Are you editing with something like MS Word? Do you print to a laser printer? Is your computer doing more than one thing at once? All of these things originated at the Xerox PARC research facility under Alan Kay around 1973. As you can see from the list of features of Xerox Alto; it more or less defined modern computing. So why aren’t we all using Xerox Alto, instead of Windows/Mac OS? In 1979, Xerox, in exchange for Apple stock, allowed some Apple engineers, including Steve Jobs, to visit Xerox Parc and look at the Alto workstation. There a lesson here; if you invent a sensational, high tech product, don’t invite competitors to come and have a good look at it.



Photoshop, written by Adobe, was an original program developed by brothers John and Thomas Knoll. Only a few products become a verb; in the UK we Hoover the carpet, people Xerox documents and now we Photoshop images. Photoshop has no serious commercial competition available to this day. Adobe is now the world leader in media software.


Visicalc was the first successful spreadsheet program, written for the Apple II computer. Successful operating systems are built upon key programs and Visicalc is the prime example. Visicalc was the first computer program that did things that were impossible with a pencil and paper system and made thousands of people realize that they needed a computer. So great was the success of the program, people would go into a computer store and ask for “a Visicalc” – meaning an Apple II.


Visicalc did it with numbers, Wordstar did it with words. Wordstar did things that, at the time, made jaws drop, such as count the words in a document. When the document was printed on a daisywheel printer, it printed one line forward and the next line backwards because it was faster that way. Suddenly, small companies could send out printed letters – unless companies could afford to employ full time typists, letters were often hand written at that time. Author Jerry Pournelle said that after seeing Wordstar, he realized that within a few years no one would write with a typewriter again. A side effect was that books became much longer.

The World Wide Web

World Wide Web

On November 12, 1990, Sir Tim Berners-Lee wrote a document outlining the basics of what we now know as the world wide web. Within the same year he created the first web server and web browser (which he called WorldWideWeb) on a NeXT computer. (NeXT was Steve Jobs’ company when he left Apple, who based its OS X on NeXT after Jobs returned). No one would have guessed the impact the web would have on the world. It is probably the most revolutionary concept in modern history. The world wide web eventually grew to such an extent that it has now become the leading source of news and entertainment for many people. It has already forced traditional enterprises like Print Media and recording/film media to completely change their whole business model. It is also thanks to this invention of Englishman Sir Tim Berners-Lee, that you are now reading this list!