Konrad Zuse begins work on Plankalkül (Plan Calculus), the first algorithmic programming language, with the goal of creating the theoretical preconditions for the solution of general problems. Seven years earlier, Zuse had developed and built the world´s first binary digital computer, the Z1. He completed the first fully functional program-controlled electromechanical digital computer, the Z3, in 1941. Only the Z4 — the most sophisticated of his creations — survived World War II.

American mathematician Claude Shannon writes The Mathematical Theory of Communication, laying the groundwork for understanding the theoretical limits of communication between people and machines. As part of this work Shannon identified the bit as a fundamental unit of information and, coincidentally, the basic unit of computation.

Mathematician Grace Hopper completes A-0, a program that allows a computer user to use English-like words instead of numbers to give the computer instructions. It possessed several features of a modern-day compiler and was written for the UNIVAC I computer, the first commercial business computer system in the United States.

John Backus completes Speedcode for IBM´s first large-scale scientific computer, the IBM 701. Although using Speedcode demanded a significant amount of scarce memory, it greatly reduced the time required to write a program. In 1957, Backus became project leader of the IBM FORTRAN project, which became the most popular scientific programming language in history and is still in use today.

An IBM team led by John Backus develops FORTRAN, a powerful scientific computing language that uses English-like statements. Some programmers were skeptical that FORTRAN could be as efficient as hand coding, but that sentiment disappeared when FORTRAN proved it could generate efficient code. Over the ensuing decades, FORTRAN became the most often used language for scientific and technical computing. FORTRAN is still in use today.

Sperry Rand releases a commercial compiler for its UNIVAC I computer. Developed by programmer Grace Hopper as a refinement of her earlier innovation, the A-0 compiler, the new version was called MATH-MATIC. Earlier work on the A-0 and A-2 compilers led to the development of the first English-language business data processing compiler, B-0 (FLOW-MATIC), also completed in 1957.

SRI International designs ERMA (Electronic Recording Machine, Accounting), for Bank of America. At the time, accounts were posted manually, a method that would quickly be outstripped by the growth in check writing after World War II. The ERMA project digitized checking by creating a computer-readable font. A special scanner read account numbers preprinted on checks using magnetic ink character recognition. In just one hour, ERMA could process the number of accounts that would have taken a well-trained banker nearly 17 workdays to complete.

A team drawn from several computer manufacturers and the Pentagon develop COBOL—an acronym for Common Business-Oriented Language. Many of its specifications borrow heavily from the earlier FLOW-MATIC language. Designed for business use, early COBOL efforts aimed for easy readability of computer programs and as much machine independence as possible. Designers hoped a COBOL program would run on any computer for which a compiler existed with only minimal modifications.

Howard Bromberg, an impatient member of the committee in charge of creating COBOL, had this tombstone made out of fear that the language had no future. However, COBOL survives to this day. A study in 1997 estimated that over 200 billion lines of COBOL code was still in existence, accounting for 80% of all business software code.

The increasing number of users needing access to computers in the early 1960s leads to experiments in timesharing computer systems. Timesharing systems can support many users – sometimes hundreds – by sharing the computer with each user. CTSS was developed by the MIT Computation Center under the direction of Fernando Corbató and was based on a modified IBM 7090, then later 7094, mainframe computer. Programs created for CTSS included RUNOFF, an early text formatting utility, and an early inter-user messaging system that presaged email. CTSS operated until 1973.

Kenneth Iverson’s book A Programming Language details a form of mathematical notation that he had developed in the late 1950s while an assistant professor at Harvard University. IBM hired Iverson and it was there that APL evolved into a practical programming language. APL was widely used in scientific, financial, and especially actuarial applications. Powerful functions and operators in APL are expressed with special characters, resulting in very concise programs.

ASCII — American Standard Code for Information Interchange — permits machines from different manufacturers to exchange data. The ASCII code consisted of 128 unique strings of ones and zeros. Each sequence represented a letter of the English alphabet, an Arabic numeral, an assortment of punctuation marks and symbols, or a function such as a carriage return. ASCII can only represent up to 256 symbols, and for this reason many other languages are better supported by Unicode, which has the ability to represent over 100,000 symbols.

Ivan Sutherland publishes Sketchpad, an interactive, real-time computer drawing system, as his MIT doctoral thesis. Using a light pen and Sketchpad, a designer could draw and manipulate geometric figures on a computer screen. Blossoming into the best known of the early drawing applications, Sketchpad influenced a generation of design and drafting programs. Although used mostly for engineering drawings, it had some artistic applications, including a famous drawing of Nefertiti that could be animated to a limited extent.

IBM introduces the SABRE reservation system for American Airlines. First tested in 1960, the system took over American’s reservations four years later. Running on dual IBM 7090 mainframes, SABRE was inspired by IBM’s work on the SAGE air-defense system. SABRE, which became a separate travel-services company in 2000, owns the Travelocity website.

Thomas Kurtz and John Kemeny create BASIC (Beginner’s All-purpose Symbolic Instruction Code), an easy-to-learn programming language, for their students at Dartmouth College who had no prior programming experience. Its use spread widely to schools all over the world. Over a decade later, most early personal computers were shipped with a version of BASIC embedded in their system, which opened up programming to an entirely new audience.

Simula, an object-oriented language, is written by Kristen Nygaard and Ole-Johan Dahl at the Norwegian Computing Center. Based largely on the Algol 60 programming language, Simula grouped data and instructions into blocks called objects, each representing one facet of a system intended for simulation. In addition to simulation, Simula also has applications in computer graphics, process control, scientific data processing and other fields.

Seymour Papert designs LOGO as a computer language for children. Initially a drawing program, LOGO controlled the actions of a mechanical "turtle," which traced its path with pen on paper. Electronic turtles made their designs on a video display monitor.

Papert emphasized creative exploration over memorization of facts: "People give lip service to learning to learn, but if you look at curriculum in schools, most of it is about dates, fractions, and science facts; very little of it is about learning. I like to think of learning as an expertise that every one of us can acquire."

Edsger Dijkstra´s "GO TO considered harmful" letter is published in Communications of the ACM, fires the first salvo in the structured programming wars. He called for abolishing the unrestricted GOTO statements used in higher-level languages, and argued that they complicated programming. The ACM considered the resulting acrimony sufficiently harmful that it established a policy of no longer printing articles taking such an assertive position against a coding practice.

CICS (Customer Information Control System), an IBM transaction processing system, is released. Before CICS was introduced, many industries used punched card batch processing for high-volume customer transactions. As it allowed online transaction processing, CICS was able to replace this method and greatly sped up the way that companies interacted with their customers.

It was first used in the public utility industry for access to customer information and transactions, but soon after its release it was quickly adopted by a wide spectrum of industries including banking, oil, insurance and even smaller companies. Although it was originally intended to only last a few years, CICS is still in use today.

AT&T Bell Labs programmers Kenneth Thompson and Dennis Ritchie develop the UNIX operating system on a spare DEC minicomputer. UNIX combined many of the timesharing and file management features offered by Multics, from which it took its name. (Multics, a project of the mid-1960s, represented one of the earliest efforts at creating a multi-user, multi-tasking operating system.) The UNIX operating system quickly secured a wide following, particularly among engineers and scientists, and today is the basis of much of our world’s computing infrastructure.

The RS-232-C standard for communications is adopted by the Electronic Industries Association. The standard permits computers and peripheral devices to transmit information serially — that is, one bit at a time. RS-232-C compatible ports were widely used for equipment like printers and modems. Compared to more modern interfaces, serial connections had slow transmission speeds, were bulky and have been largely replaced by USB ports on new PCs and peripheral equipment.

The Pascal programming language, named after Blaise Pascal, a French physicist, mathematician and inventor turned philosopher, is introduced by Professor Niklaus Wirth. His aim with Pascal was to develop a programming language applicable to both commercial and scientific applications, and which could also be used to teach programming techniques to college students. It was closely based on ALGOL 60, which Wirth had also helped to develop.

The C programming language is released. Dennis Ritchie and his team created C based on the earlier language BCPL (Basic Combined Programming Language) and soon after re-wrote the source code for Unix in C. As such, Unix was easily ported to other computers and spread swiftly. C is still widely used today.

Gary Kildall develops the first commercially successful operating system for microcomputers, CP/M. He and his wife established Intergalactic Digital Research (modestly dropping “Intergalactic” later) to market it. CP/M made it possible for one version of a program to run on a variety of computers built around eight-bit microprocessors. At one point Digital Research and Microsoft were approached by IBM about providing an operating system for its PC. Microsoft won the competition with its own operating system, called MS-DOS.

Rob Barnaby creates WordStar while at MicroPro International. Among the first popular word processing systems for personal computers, WordStar originally ran on the CP/M operating system, and later on DOS and Windows. In 1981, it had significant market share, in part because it came bundled with the Osborne 1 computer. WordStar retained a loyal following well after Microsoft Word surpassed it in sales.

Harvard MBA candidate Dan Bricklin and programmer Bob Frankston develop VisiCalc, the program that turned the personal computer into a business machine. Initially developed for the Apple II, whose sales it boosted, VisiCalc automated the recalculation of spreadsheets, allowing users to ask “What if?” questions of their financial information.

MS-DOS, or Microsoft Disk Operating System, the basic software for the newly released IBM PC, is the start of a long partnership between IBM and Microsoft, which Bill Gates and Paul Allen had founded only six years earlier. IBM’s PC inspired hardware imitators in the 1980s, but for software, most licensed MS-DOS. MS-DOS was eventually supplanted by Microsoft’s Windows operating system.

Mitch Kapor develops Lotus 1-2-3, a software suite for the IBM PC based on a word processor, spreadsheet, and database. It quickly became the first “killer application” for the IBM PC, and contributed to the success of the PC in business. IBM purchased Lotus in 1995.

Microsoft announces Word, originally called Multi-Tool Word. In a marketing blitz, Microsoft distributed 450,000 disks containing a demonstration version of its Word program in the November issue of PC World magazine, giving readers a chance to try the program for free. It competed with WordPerfect for market share as a word processing program, and it was not until Microsoft Word for Windows was introduced in 1989 that it became a global standard.

Richard Stallman, a programmer at MIT’s Artificial Intelligence Lab, set out to develop a free alternative to the popular Unix operating system. This operating system called GNU (for Gnu's Not Unix) was going to be free of charge but also allow users the freedom to change and share it. Stallman founded the Free Software Foundation (FSF) based on this philosophy in 1985.

While the GNU work did not immediately result in a full operating system, it provided the necessary tools for creating another Unix-type system known as Linux. The software developed as part of the GNU project continues to form a large part of Linux, which is why the FSF asks for it to be called GNU/Linux.

Matlab (Matrix Laboratory), a high-level programming language, is released. It was designed by Professor Cleve Moler of the University of New Mexico and was initially intended to help students use mathematical software libraries without requiring knowledge of the scientific programming language FORTRAN. Its roots began in the academic community, but it spread quickly to many other areas of technical computing and is widely used today.

Phil Moorby and Prabhu Goel of Gateway Design Automation create Verilog, a hardware description language that is used in the design of digital circuitry. Initially designed for Gateway’s Verilog XL Design Logic Simulator, it was a vast improvement over methods being used by circuit designers at the time.

Gateway Design Automation was acquired in 1989 by Cadence Design, which released the Verilog Hardware Description Language (HDL) into the public domain the following year. Verilog is now one of two hardware description languages used in the world today to design complex digital systems.

The C++ programming language emerges as the dominant object-oriented language in the computer industry when Bjarne Stroustrup publishes the book The C++ Programming Language. Stroustrup, from AT&T Bell Labs, said his motivation stemmed from a desire to create a language that would allow for more complex programs and which combined the low-level features of BCPL with the high-level structures of Simula.

According to Stroustrup: "C++ is a general purpose programming language designed to make programming more enjoyable for the serious programmer.”

Aldus announces its PageMaker program for use on Macintosh computers, launching the desktop publishing revolution. Two years later, Aldus released a version for the IBM PC. Developed by Paul Brainerd, PageMaker allowed users to combine graphics and text easily into professional quality documents.

Pagemaker was one of three components to the desktop publishing revolution. The other two were the invention of Postscript by Adobe and the LaserWriter laser printer from Apple. All three were necessary to create a desktop publishing environment.

Perl (Practical Extraction and Report Language) is written by Larry Wall. It was intended to facilitate report processing and could scan and extract information from text files and ultimately create reports generated from that information. It was designed for ease of use and quick programming and has found multiple applications in every branch of computing. It is very useful in making other programs work together and has been called “the duct tape of the Internet.”

Apple engineer William Atkinson designs HyperCard, a software tool that simplifies development of in-house applications. In HyperCard, programmers built “stacks” of information with the concept of hypertext links between stacks of pages. As a stack author, a programmer employed various tools to create his own stacks, linked together as a sort of slide show. Apple distributed the program free with Macintosh computers until 1992. Hypercard influenced the creation on the Internet protocol HTTP and JavaScript.

Mathematica is created by Stephen Wolfram, a British scientist. It was a symbolic mathematical programming language used in mathematical, scientific, academic, and engineering fields. Mathematica was a complete ecosystem for computing that allowed symbolic entry of mathematical functions and equations as well as graphical display of the results.

Microsoft ships Windows 3.0. Compatible with DOS programs, the first successful version of Windows finally offered good enough performance to satisfy PC users. For the new version, Microsoft updated the interface and created a design that allowed PCs to support large graphical applications for the first time. It also allowed multiple programs to run simultaneously on its Intel 80386 microprocessor. Microsoft lined up a number of other applications ahead of time that ran under Windows 3.0, including versions of Microsoft Word and Microsoft Excel. As a result, PC users were exposed to the user-friendly concepts of the Apple Macintosh, making the IBM PC more popular.

Photoshop is released. Created by brothers John and Thomas Knoll, Photoshop was an image editing program and the most popular software program published by Adobe Systems. Thomas, while earning a PhD at the University of Michigan, had created an early version of the program in 1987, and John saw a practical use for it as a special effects staff member at Industrial Light & Magic. It was then used for image editing in the “pseudopod” scene in the movie The Abyss. When Adobe saw potential in the project they bought a license for distribution in 1989 and released the product on February 19, 1990.

Designed by Finnish university student Linus Torvalds, the Linux kernel is released to several Usenet newsgroups. Almost immediately, enthusiasts began developing and improving it, such as adding support for peripherals and improving its stability. In February 1992, Linux became free software or, as its developers preferred to say after 1998, “open source.” Linux also incorporated some elements of the GNU operating system and is used today in devices ranging from smartphones to supercomputers.

Pretty Good Privacy, or PGP, a public-key encryption program, is introduced and is used for securing texts, emails and files. Its inventor, software engineer Phil Zimmermann, created it as a tool for people to protect themselves from intrusive governments, businesses, and institutions around the world. Zimmermann posted PGP on the Internet in 1991 where it was available as a free download. The United States government, concerned about the strength of PGP, which rivaled some of the best secret codes in use at the time, prosecuted Zimmermann but dropped its investigation in 1996.

FreeBSD, a complete Unix-like operating system is launched. It was the most widely used open-source BSD (Berkeley Software Distribution) variant. After its initial release, the software was significantly re-engineered due to a lawsuit between Unix copyright holder Unix Systems Laboratories and the University of California, Berkeley. The lawsuit revolved around source code in Berkeley’s 4.3BSD-Lite which was the basis of the FreeBSD operating system. FreeBSD incorporated features including networking, storage, security, portability and Linux compatibility.

Microsoft Windows NT is released. Work on the project began in the late 1980s in an effort spearheaded by a group of former Digital Equipment Corporation employees led by Dave Cutler. It was the first truly 32-bit version of Windows from Microsoft, which made it appealing to high-end engineering and scientific users that required better performance. A number of subsequent versions of Windows were based on NT technology.

The PDF format was developed by Adobe Systems. Its main purpose was to create a universal file format that would preserve the visual integrity and layout of documents across different computer systems, software, and printers. Before PDF, sharing documents electronically often led to formatting issues, as various software and devices interpreted files differently. PDF has revolutionized the way documents are shared, accessed, and preserved.

Java 1.0 is introduced by Sun Microsystems. The Java platform’s “Write Once, Run Anywhere” functionality let a program run on any system, offering users independence from traditional large software vendors like Microsoft or Apple. The project was a successor to the Oak programming language created by James Gosling in 1991.

JavaScript, an object-based scripting language, is developed at Netscape Communications by Brendan Eich. It was used extensively across the Internet on both client and server sides. Although it shared its name with the Java programming language, the two are completely different.

On August 24th, 1995, Microsoft's Windows 95 operating system was launched with one of the most sweeping media campaigns in the history of computing. A $300 million promotional blitz included television commercials using the Rolling Stones' song "Start Me Up," as well as a 30-minute promotional video starring actors from the top-rated television comedy "Friends," made it one of the most anticipated product launches in American business history.

Windows 95 was a major improvement over the previous Windows 3.1, adding features such as “Plug and Play” for more easily installing new peripherals, as well as the Taskbar and Start button menu. More than one million units were sold in the first four days following the release, and within two years, Windows 95 was installed on more computers than any other operating system.

Microsoft introduces Visual Studio. Bundled within Visual Studio were a number of programming tools, as Microsoft’s intent was to create a single environment where developers could use different programming languages. The idea of visual programming is to allow programmers to develop software using built-in visual elements (like in a block diagram) instead of text.

During the late 1990s, the impending Year 2000 (Y2K) bug fuels news reports that the onset of the year 2000 will cripple telecommunications, the financial sector and other vital infrastructure. The issue was rooted in the fact that date stamps in most previously written software used only two digits to represent year information. This meant that some computers might not be able to distinguish the year 1900 from the year 2000. Although there were some minor glitches on New Year’s Day in 2000, no major problems occurred, in part due to a massive effort by business, government and industry to repair their code beforehand.

BitTorrent, a peer-to-peer file sharing service, is launched by BitTorrent, Inc. It was developed by Bram Cohen and was initially an open source program, but became closed source in 2005. BitTorrent enabled users to upload and download files, typically music and movies. It came under scrutiny of copyright holders – such as the music and motion picture industries -- which claimed BitTorrent facilitated theft of their intellectual property.

Mac OS X is released. It was a significant departure from the classic Mac OS as it was based on the Unix-like operating systems FreeBSD, NetBSD and NeXTSTEP/OpenStep. OS X introduced a more stable and reliable platform and multiple applications could more efficiently be run at the same time. The Mac OS X 10.6 ("Snow Leopard") update, released in 2009, completed the Mac's transition from a 32-bit to a 64-bit operating system.

The Windows XP operating system is released. Based on the Windows NT kernel, XP was considered more stable than previous versions of the operating system. XP was widely adopted by industry and persisted much longer than Microsoft planned. For example, in 2014, 95% of the world’s automated teller machines ran XP. Microsoft support for XP ended on April 8, 2014.

Apple’s iTunes is released. It was based on Bill Kincaid’s SoundJam MP software, the rights to which Apple purchased. Initially, iTunes was only supported on the Mac operating system and functioned as a media player and media management tool. iTunes allowed users to record music from CDs, bring it into iTunes, mix it with other songs and then burn a custom CD. When the Apple iTunes music store was launched in 2003, it transformed music distribution and the entire music industry. Less than a week after its launch, over one million songs were downloaded. By 2013, over 25 billion songs had been downloaded from the iTunes store.

Hadoop is an open source software project initially developed by Google as a means of extracting search results from large amounts of unstructured data, such as data found on the web. It was used by many large corporations where networked scalability, cost effectiveness and fault tolerance were critical to their business models. Companies such as Google, Yahoo, American Airlines, IBM and Twitter all used Hadoop, and it could be scaled from a single server to thousands. With Hadoop different types of data could be seamlessly integrated and Hadoop could redirect work to another system if a node failed in the cluster.

Scratch is released to the public. A free programming language that focused on education, it was designed by a team led by Mitchel Resnick at the MIT Media Lab Lifelong Kindergarten Group. Intended to be used by educators, students and parents as a teaching language, it had a number of applications in educational settings. These included math, computer science, language arts and social studies. Its interface allowed novice users to stack and organize block commands to write programs. Scratch has millions of users worldwide and is available in more than 40 languages.

The Stuxnet virus is widely reported in the media due to attacks centered in Iran. The virus attempted to damage uranium enrichment centrifuges used in Iran’s nuclear development program by causing damaging speed variations. Although it was recognized that some centrifuges were rendered inoperable by the virus, the full extent of the damage remained unknown. Stuxnet brought attention to the fragile nature of global infrastructure in a networked world.

Adobe Creative Cloud is announced as a subscription and cloud-based model of distribution for its major software products. Adobe Acrobat, Illustrator, Dreamweaver, Photoshop, and others, could be subscribed to either as a complete package or individually to suit user needs. This model also allowed Adobe to begin releasing continuous updates to their products, shortening the development cycle and the time need to incorporate new features.

Instagram, an image-sharing and social networking application, is purchased by Facebook for nearly $1 billion. It was initially launched in October 2010 by founders Kevin Systrom and Mike Krieger and became an instant hit, with over 100 million active users by early 2013. Photos and videos (with 15 second maximum length) could be shared among users, who could then annotate these images with specific hash tags to enable them to be easily shared among other social media platforms such as Twitter and Facebook. Instagram also allowed users to manipulate their photos with a variety of digital filters such as “Slumber,” “Kelvin,” “1977,” “Sierra,” and “Inkwell.”

An updated Microsoft Office 365 is announced. It was a subscription-based software product. Microsoft’s Word, Excel, OneNote, PowerPoint, Outlook, Access, and Publisher were all available in packages for a monthly or annual subscription. Also included with a subscription was 1 TB of cloud storage on Microsoft’s One Drive (formerly Skydrive). Home, personal, university, business, and enterprise subscription plans were made available for a wide range of users. Microsoft’s change to a subscription model was not unique: Apple, Adobe, IBM and many other large software and technology companies adopted this model as well.

The Apple Pay mobile payment system is introduced into Apple’s product ecosystem. Initially only available for the iPhone 6 and 6 Plus, iWatch, iPad Air 2, and iPad Mini 3, many major banks and credit card companies participated in the Apple Pay system. The device’s near field communications (NFC) interface, Passbook app, and Apple’s Touch ID system worked in tandem with point-of-sale systems in retail outlets to complete transactions. Apple Pay could also be used for online purchases.

HTML 5 is announced as the successor to HTML 4, which had become the standard for web markup languages in 1997. Markup languages describe how web pages will look and function. Work on HTML 5 had begun in 2004 under the auspices of the Web Hypertext Application Technology Working Group. It was simplified compared to its predecessors and was intended to be human-readable. HLTML 5 also offered a number of improvements for multimedia, such as simplifying the embedding of content such as streaming video and games into web pages.

The Heartbleed bug is uncovered as a dangerous security flaw in the code base of the OpenSSL cryptographic software library. OpenSSL protected a significant portion of the world’s web servers, and nearly 20% of them were found to be vulnerable to attack from this particular security bug, which allowed hackers to eavesdrop on the communications of unsuspecting victims and steal sensitive information such as user names and passwords, emails, instant messages, and even confidential files and documents. Although it was a dangerous and widespread bug, installation of the “Fixed OpenSSL” library by service providers and users greatly reduced its effectiveness.