Charles Lindsey's Home Page

So who is Charles Lindsey?

Oh! I thought you knew that! Why else are you looking here?

OK then, here it is.

I used to be a Senior Lecturer in the Department of Computer Science at the University of Manchester (and before that I worked for Ferranti/ICT, and before even that I was a Research Student at the Mathematical Laboratory in Cambridge). In September 1992 I took Early Retirement, but I am still involved with various computing projects.

And I also brought home my SPARCstation, so that I could continue to do interesting things on it. Well it soon morphed into various other Sun hardwares, and finally into a conventional Intel machine running Ubuntu.

My interests

Well, everything to do with computers really, but particularly with how to make them do what you want. Hence my particular interest in Programming Languages, and in one language in particular:


"The Language that Never Was", as some might say. But it was used for productive programming, and it established many ideas now familiar in later languages (Pascal, C, C++, SML, Ada). Although I was not involved in the original development of the language, you will find my name amongst the Editors of the Revised Report, and as an author of its Informal Introduction. For the full gory story, see my paper in History of Programming Languages-II (ACM Press).

There are currently two compilers available for Algol 68.  Algol 68 Genie  is the front runner, and is exceedingly comprehensive; then there is algol68toc obtainable from

And I can still provide you with my own ALGOL 68 compiler but it only runs on some pretty ancient hardware.

Structured Programming

I wrote a paper entitled Structure Charts which appeared in SIGPLAN Notices for November 1977. It introduces (yet another) alternative to flowcharts, and also makes provision for gotos which can be "considered harmless".

I am not sure whether the Copyright belongs to ACM or to me but as Author I am certainly allowed reproduce it here, and you are welcome to read it or to link to it, but if you want to copy or do anything else with it you had better download it yourself from the ACM Digital Library and adhere to their Terms and Conditions.

Computer Conservation

I am a member of the Computer Conservation Society North West Branch.

I have been taking an active interest in Hartree's Differential Analyser, a mechanical analogue machine built in 1936, part of which is on display in the Museum of Science and Industry in Manchester. In 1994, I did a survey of the machine with a view to having it restored to working order; I was thanked politely, but no it is not "our policy" to restore it. I5 years later, they suddenly changed their tune, and I led a CCS working party to get it running in 2010. You can see the results or our endeavours here and some slides relating to the movie "When Worlds Collide" from a talk I gave here. Then, in 2015, just as  it was working nicely, they pulled the rug from underneath us. They wanted to use the space of the Computer Gallery for something else. They would not even let us make a final video of the machine in operation. They promised that they would let me oversee its dismantling, and then in 2016 when they brought in outside contractors to do the job they would not let me near it. So goodness knows what state it is now in, or whether they preserved all the spare parts, special tools, etc. that we had accumulated. And to the best of my knowledge that space is still unused, since they then discovered that the building (Listed) was in a bad state of repair and there were no funds to fix it. I have lost confidence in that Museum, and indeed in all branches of the Science Museum - they are expert at running museums but have no real knowledge of science.

In the meantime, I have been restoring a Meccano Differential Analyser made in 1947 by Nicholas Eyres (who had worked with Professor Hartree on the original machine during the war). I shall then make videos of it in operation, and after that I shall look for a good home where it will be maintained and exhibited.

Usenet UK

I have been an avid reader of Usenet newsgroups for many years. It is my firm belief that they are a Good Thing, even though hardly anybody is aware of them now because umpteen websites run their own discussion groups, usually paid for by advertising - and nobody makes any money out of Usenet so it receives no publicity.

In early 1995, when the present explosion in Internet Connectivity was taking off, the uk.* usenet hierarchy was in a shambles. It was originally the creature of the University of Kent, which was fine when that was the only source of connectivity to North America  around. Now everybody was in on the act, people were clamouring for more groups, but there was noone to decide what was, and what was not, an "official" newsgroup within uk.*. Everybody was talking, but nobody was actually doing anything, and new and worthwhile groups were not getting created.

So I decided to do a bit of Banging Together of Heads. I set up a mailing list known as 'Newscoord' of people who seemed willing to look at the problem seriously, and I got the three main UK ISPs on board. Then we produced some Guidelines, and a Voting procedure, and a suggestion for a Committee to oversee them. And we put it all before the readers of where, after much debate and argument, the proposals were voted on and adopted by a substantial majority.

So now the uk.* hierarchy is run by this Committee, of which I am a member (having regularly been re-elected to further three year terms). And then the uk.* hierarchy became strong and healthy, and grew like Topsy.

See the Committee's official Web Page for all the details.

Netnews Articles and Architecture

I was heavily involved in the IETF Working Group which produced the two standards RFC 5536 and RFC 5537 which provide the specification of how Usenet works, and in both of which I am listed as an author.

I was also a member of the IETF DKIM Working Group (see which produced a scheme for signing headers of emails.

Regulation of Investigatory Powers Act

I became interested in matters relating to the various stages of the Government's attempts to gain access to encrypted communications which lawfully came into its possession as a result of my membership of the UKCrypto Mailing List, and I submitted my comments to the various consultative documents as they appeared. For example Comments on the DTI proposals (written in 1999) illustrates some of the terrible misunderstandings of cryptographic Best Practice within Government circles at that time.

When the R.I.P. Bill was finally published, I prepared various documents addressing problems with that Bill, some of which are reproduced below. These relate to the situation  as the Bill entered the House of Lords, and are now only of historical interest. I worked closely with various member of parliament, in both houses, and prepared many amendments. Whilst these amendments did not directly affect the form of the Bill, the collective furore created by my colleagues on the UKCrypto list and by others involved as ISPs or as practitioners of E-Commerce was effective in persuading the Government to make significant changes to the Bill (notwithstanding which, the Act as finally passed is still a Dog's Dinner).

The documents I produced during the course of the Bill's passage include:

Much of the detailed implementation of the Act is covered by a Code of Practice, which was not finalised until 2006. I, and many others, had submitted comments on the Drafts which preceded it, most of which had been taken into account, so it is a much cleaner document than the Act itself. Subsequently, the Act itself has had a major overhaul, but neither I, nor the UKCrypto mailing list, played any part in that.

Critique of PGP Key Generation

This is a record of my investigation into the source code of PGP to see whether it contained any Trojan that might compromise the security of the keys that it generates. I uncovered various oddities, but nothing to compromise its basic soundness. It refers to version 2.6.3 of PGP, so it may be a little dated now.

Owners of PGP web pages, please feel free to point at this (but check periodically that it is still there).

The Great SPARC Floppy Muddle

The story of how I tried to move a Floppy Drive from a Sparcstation-5 to an Ultra-2, and what I learnt about SUN's treatment of floppies in the process.


ALGOL 68S Compiler

This compiler currently runs on

and it could easily be made to run under Linux if someone will kindly volunteer to do a little hacking (not much).

Click here to find out more.

The Secondary Selection

For years I have been using Sun hardware running the Solaris operating system, and have been using the secondary selection, an established feature of X-Windows, when editing texts. On switching to Linux in X86 hardare, I was horrified to find that this feature was not supported, so I set about hacking the GTK+ toolkit to rectify this state of affairs. Click the link to find out more.

Useful Information about me

My email address.

My Phone Number
+44 161 488 1845

Snail Mail
Apt 40, Dutton Court, Station Approach, CHEADLE HULME, SK8 5BF, U.K

PGP Public Key
820-bit key, key ID
2C15F1A9, created 1997/01/08


Version: PGPfreeware
5.0i for non-commercial use