Historic software editor released for general use

One of the world’s early computer software editors, developed by The University of Adelaide and still in use today, is being released for free use by developers around the world.

Ludwig, a ‘full-screen’ editor, was originally designed by staff at the School of Computer Science to enable software development on the university’s first VAX (Virtual Address eXtension) interactive computers, bought to replace the previous systems of punch cards, printed output and batch processing. The university bought three Digital Equipment VAX-11/780 computers for both teaching and research use in 1979 — the first commercially available 32-bit computers.

“At the time, these computers represented a major shift in computing power and teaching for the university,” said Emeritus Professor Chris Barter, who led the Ludwig development team.

“Users could now interact directly with the computers using video terminals located around the campus, in student laboratories or a researcher’s own office.”

A core component of the new interactive computing was the ability to support editing of text — usually computer programs — directly on the computer system. At the time, most computer text editors were difficult-to-use ‘line editors’, allowing access to a single line of text at a time — and requiring significant effort to master.

The full-screen editors that were available at the time provided an environment that was easier to use and more productive, but were typically very resource hungry and only available on a few computer systems, which did not include the VAX computers. With this in mind, Professor Barter and three programmers designed and constructed Ludwig v1.0 — for which there was no equivalent in Australia at the time.

“The ability to host 20 to 30 simultaneous users, all editing and developing programs, plus many more users running programs, on a machine boasting a scant one million instructions per second and 4 MB of memory, was world beating,” said Professor Barter. “Ludwig was also easy to learn and use and had significant power — it was taken up by users throughout Australia and worldwide.”

Over the years further developments took place including adapting Ludwig to later computer systems, including Unix, Linux and Microsoft Windows. The editor is still in use today, with a small number of people who have developed Ludwig further currently under restricted licences for their own private use.

Now, to enable these developments to be consolidated and made freely available, the university has released Ludwig and its source code under the MIT Open Source License. This means the features of Ludwig that are not found in other text and code editors will be now open to all developers.

The release has been welcomed by Open Source Industry Australia (OSIA), with company secretary and director Jack Burton saying, “Open sourcing Ludwig will help attract a broader community of contributing developers and end users as this historically significant software continues to evolve in the future.”

The university retains copyright and will be acknowledged in the copyright header on all Ludwig source files, under the MIT licence arrangements. Files will be made accessible on the open source repository GitHub.

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