Wish: MAVIS computer recreation in Mode 7

[OneSwitch]

I'm looking for anyone with good BBC Model B programming skills, who would be interested in working with me to recreate an as accurate as possible simulation of the amazing MAVIS Mk.II computer built by Ferranti. Much more on it here: https://oneswitch.org.uk/page/016. The plan would be to make it available on-line using the Godbolt emulator system, and post-Covid, for a museum showcase.

MAVIS (The Microcomputer Audio Visual Information System) was a computer in a suitcase, aimed at enabling a very wide range of disabled people. The project was initially led by Dr. Christopher Evans at the National Physical Laboratory (and author of the Mighty Micro book and television series), who is said to have inspired much that led to the BBC's IT literacy project, and as such the BBC Micro.

The computer opened up all kinds of independent avenues for some very disabled children. It opened up art, music, communication, writing, reading, games, environmental control and more. Would love to give it more life, and more credit with an interactive approximation of what it was like.

Please get in touch here, via direct message, or via oneswitch@gmail.com.

Thanks for reading.

Barrie
OneSwitch.org.uk

[dp11]

I have a Mavis tape in the loft. Of course it hasn't be played in >40years . I wonder if you want to try and get the programs off it ?

[OneSwitch]

Blimey! Yes please, that would be beyond my initial hopes... A photo would be brilliant too.

What's the history of it ending up in your loft?

[Pernod]

It's a shame that none are known to have survived, otherwise I'd be able to emulate it.

[OneSwitch]

That's the dream, Pernod. I've not given up hope. That said, I have contacted Julia and David Schofield (worked on the project), the National Physical Laboratory, Banstead, Richard Cloudesley School, Joanne's Mum Syvlia Dawson with no luck there tracking down a MAVIS Mk.II. I've failed to get hold of Reg Maling's son or any other relative too.

But there's still a chance...

[scruss]

Neat system, and a real shame it was lost.

The 2.308 MHz Z80 is a frequency I haven't seen before. Wonder if it was a standard design pressed into service? The project dodged a bullet not using bubble memory, though — great in theory, unreliable in practice.

[BigEd]

Interesting to read about the machine, Barrie, thanks for putting the materials together. I note the Teletext solution at that time was a two-chip solution.

I might guess that the Z80 clock frequency has something to do with the speed of the teletext subsystem. But it would only be a guess.

Dominic, if you could take a 16 bit stereo sample of that tape and share it, that could be very interesting. Although I see in the docs that a 'digital cassette recorder' supporting 'phase encoding' is expected. But it can't hurt to see what you can see.

[dp11]

I lied when I said I have "a" tape in the loft

[OneSwitch]

Neat system, and a real shame it was lost.

The 2.308 MHz Z80 is a frequency I haven't seen before. Wonder if it was a standard design pressed into service? The project dodged a bullet not using bubble memory, though — great in theory, unreliable in practice.

Just a year or ten ahead of its time I feel. They didn't manage to dodge the bullet of unreliable cassette loading and saving from what I've read. Makes me wonder if much can be salvaged from Dominic's tapes, but I'm completely fascinated to find out.

[OneSwitch]

Interesting to read about the machine, Barrie, thanks for putting the materials together. I note the Teletext solution at that time was a two-chip solution.

I might guess that the Z80 clock frequency has something to do with the speed of the teletext subsystem. But it would only be a guess.

Dominic, if you could take a 16 bit stereo sample of that tape and share it, that could be very interesting. Although I see in the docs that a 'digital cassette recorder' supporting 'phase encoding' is expected. But it can't hurt to see what you can see.

It's been a pleasure pulling it together. The people who were involved with the project I've spoken to have all been lovely to boot. Wish I had a time machine to get a chance to speak to Christopher Evans, Joanne (or any of the MAVIS users) and Reg Maling. All fascinating people. Maybe in the next life.

Agree on the hope of getting a good quality copy of the tapes ASAP. Them being on mini-cassette might make things a little trickier.

[OneSwitch]

I lied when I said I have "a" tape in the loftDSC_0578.JPGDSC_0577.JPG

Nicely hoarded, Dominic! I wasn't sure if it was a micro-cassette system or not. That settles it for MAVIS Mk.II. But do you have any means of getting a digital copy? And do you have any idea at all what's on them? I imagine the Dominic labelled one is your art work / music / text documents, would you think too?

[BigEd]

Ahem, oh, not compact cassette then - that's an extra bit of a hurdle.

[OneSwitch]

Wondering if one of those on-line mini-cassette transfer services might be the way to go. They'd be very careful you'd hope...

[BeebMaster]

I have an Olympus Pearlcorder S720 but it looks to take "micro" rather than "mini" tapes, I don't think these would fit it would they? Maybe there's an adapter to a normal-sized cassette tape like you used to be able to get to convert camcorder videotapes to VHS sized tapes?

[BeebMaster]

Just had a look and I've got a mini-cassette as well, they are slightly longer than the micro ones. I don't have the machine for that but I should be able to get my hands on a dictaphone or even transcriber which takes these mini tapes as I used to use them regularly. Would that be any use?

[OneSwitch]

Just had a look and I've got a mini-cassette as well, they are slightly longer than the micro ones. I don't have the machine for that but I should be able to get my hands on a dictaphone or even transcriber which takes these mini tapes as I used to use them regularly. Would that be any use?

Thanks, BeebMaster. That might be very handy. Waiting to hear back from Dominic. My instinct is to find someone willing with a well maintained mini cassette playing machine, as chewing up the tapes would not be good at this time. Totally up to Dominic though right now.

[BigEd]

Found a little out about data on mini-cassettes. They are spool-driven, so no capstan, and therefore variable tape speed. Perhaps less risk in the simpler transport system. But note also that the tape's the same width as compact cassettes. See this service manual (PDF) for waveforms, dimensions, and so on. See also this PDF but I think it's a subset. If anyone has a Philips P2000 that uses minicassette too.

If push came to shove, transplanting the tape into a compact cassette and running it through a barebones datarecorder might give a train of pulses which could be decoded at leisure. But there is a risk of tape damage. Don't expect to use audio techniques for this!

[dp11]

Thanks for this.

I have some dictaphones so I wonder if they have enough bandwidth to get the signal off.

[OneSwitch]

Don't know if useful, but (once upon a time) the technical reports on MAVIS Mk.II could be found from a Mr. P. Watson (Chief Engineer) at Ferranti Instrumentation, Moston Works, St. Mary's Road, Moston, Great Manchester... I wonder if he can be tracked down.

I have some additional technical information I can start to add to this folder: https://www.dropbox.com/sh/7dftsc1k6hts ... I53Ia?dl=0. Not much there now, but might be of some use. I don't have anything very detailed though.

[BigEd]

I have some dictaphones so I wonder if they have enough bandwidth to get the signal off.

Using a dictaphone for tape transport and perhaps tapping off the signals from the tape head might be a win. Clean it first!

[dp11]

I'm going to have to think again. The tapes are a different size.

[OneSwitch]

I'm going to have to think again. The tapes are a different size.

If I understand correctly, MAVIS used mini-cassettes, the size inbetween the larger and much more common compact-cassettes, and the smaller mico-cassette most often used for dictating machines.



If it helps, I'd be happy to arrange to buy you a mini-cassette recorder from eBay. There's dozens of them there.

[OneSwitch]

This may be of interest from GeoffB17: viewtopic.php?p=305376#p305376

"I have some software (using PHP) called hxtape which will read a .WAV file and produce ASCII data, and I have used this with a data file created by the HX and it works, but the prog is set up for the structure of the HX recording and may do nothing with this file, but I'll give it a go and see if it sees anything. I have the full source for the prog, so it could be altered once I know the structure, and PHP is interpreted."

Would this suggest we'd need to find more technical specs for the MAVIS system (if at all possible)?

[OneSwitch]

Small update to the MAVIS page with a high-res picture: https://www.oneswitch.org.uk/IMAGES/MUS ... -MAVIS.jpg

And, I don't know if use, but some sort of ASCII codes here: https://www.dropbox.com/s/59e74dq31t7dq ... R.jpg?dl=0

[BigEd]

I see there's a mention in Turing's Legacy by Yates, but that's not a book I have.

And there's an early mention on the front page of a 1977 Computer Weekly Supplement:

Transcript:

Mavis - a match for any handicap

A MICRO-BASED system developed by a team at the National Physical Laboratory, Teddington, which enables the handicapped to communicate and interact with their environment, was put on show to organisations for the handicapped last week.

Nicknamed Mavis — an acronym for Microprocessor-based Audio Visual Information System — it Is the first system of its kind and took the team, under project leader Dick Penn, 18 months to develop.

Based on a Motorola 6800, Mavis features a colou, television as the display. This is for economy and because they are already in widespread use.

“It Is the embryo of what things will become," said Dr Chris Evans, head of the man/computer interaction group at NPL. "Mavis is extremely flexible and can be tailored to almost any handicap."

For those with severe handicaps the puff-suck tube shown below by Dr Rudi Dallos, psychologist of the team, can be used. By the correct combination of breaths a cursor can be made to select characters from a matrix and "write" them on the screen as If by a keyboard.

Also, there is a "talking arithmetic program" (pictured left with Julia Howlett, her guide dog, and Tim Folkard) which does elementary sums, and a music program which allows simple tunes to be constructed and played.

Mavis presently handles Teletext broadcasts, but will eventually accept Viewdata as well. Cost of the final system will be "under £1,000".

Captions:
Dr Rudi Dallos demonstrates the puff-suck mouthpiece.
Julia Howlett and her guide dog Beulah come to terms with Mavis.

(Hope these are new finds, but I confess I haven't checked)

[OneSwitch]

I see there's a mention in Turing's Legacy by Yates, but that's not a book I have.

And there's an early mention on the front page of a 1977 Computer Weekly Supplement:
Mavis-CW-1977-09-15.png

Transcript:

Mavis - a match for any handicap

A MICRO-BASED system developed by a team at the National Physical Laboratory, Teddington, which enables the handicapped to communicate and interact with their environment, was put on show to organisations for the handicapped last week.

Nicknamed Mavis — an acronym for Microprocessor-based Audio Visual Information System — it Is the first system of its kind and took the team, under project leader Dick Penn, 18 months to develop.

Based on a Motorola 6800, Mavis features a colou, television as the display. This is for economy and because they are already in widespread use.

“It Is the embryo of what things will become," said Dr Chris Evans, head of the man/computer interaction group at NPL. "Mavis is extremely flexible and can be tailored to almost any handicap."

For those with severe handicaps the puff-suck tube shown below by Dr Rudi Dallos, psychologist of the team, can be used. By the correct combination of breaths a cursor can be made to select characters from a matrix and "write" them on the screen as If by a keyboard.

Also, there is a "talking arithmetic program" (pictured left with Julia Howlett, her guide dog, and Tim Folkard) which does elementary sums, and a music program which allows simple tunes to be constructed and played.

Mavis presently handles Teletext broadcasts, but will eventually accept Viewdata as well. Cost of the final system will be "under £1,000".

Captions:
Dr Rudi Dallos demonstrates the puff-suck mouthpiece.
Julia Howlett and her guide dog Beulah come to terms with Mavis.

(Hope these are new finds, but I confess I haven't checked)

Thanks, I really appreciate you looking, even though I have seen both of those. The Turing's legacy book is a really good read, with loads on the National Physical Laboratory projects, when they had more government funding to do exciting imaginative things. Would love to see a good quality scan of that 1977 article. I have some more here: https://www.dropbox.com/sh/uy5s61wvvq4h ... TuKia?dl=0

[BigEd]

Ahem, sorry about that. In normal times, I'd visit The National Museum of Computing at Bletchley Park a couple of times a year, and they have Computer Weekly, probably no problem to take a snap. (I've found photos are almost as good as scans.)

[OneSwitch]

Ahem, sorry about that. In normal times, I'd visit The National Museum of Computing at Bletchley Park a couple of times a year, and they have Computer Weekly, probably no problem to take a snap. (I've found photos are almost as good as scans.)

That would be really appreciated. One day in the not too distant future perhaps?

Something exciting came to my attention today, from 1 of 4 new colour MAVIS related photos.

https://www.dropbox.com/s/4i5jn2m6lh6z99x/CROP.jpg?dl=0

Seems that there was a film made with MAVIS in it. NPL Library not accessible at the moment, but I've put a search request in. Fingers crossed. Unless anyone has a VHS copy somewhere...

[BigEd]

It'll be interesting to see that film!

Yes, of course, when I next get to TNMoC, I need only remember to get hold of the right CW issue. And it might well be this year, depending only on how the future unfolds.

[OneSwitch]

It'll be interesting to see that film!

Yes, of course, when I next get to TNMoC, I need only remember to get hold of the right CW issue. And it might well be this year, depending only on how the future unfolds.

Many thanks. Appreciated.

What happened instead of MAVIS is partly a well-known tale. The Micros in Schools project (50% funding towards computers) helped. For special schools, there was support for special interfaces and for most of the 1980s a network of resources including bricks-and-mortar SERMERCs (Special Education Microelectronic Resource Centres) where people could get assessed and try out the latest and best hardward and software they had. There was the Blue File database full of documents and often free to copy software that could be shared pre. easy internet access days.

1. New Scientist (October 1981): https://www.dropbox.com/s/7simvwix04577 ... t.jpg?dl=0
2. Parliament reords (October 1981): https://api.parliament.uk/historic-hans ... al-schools.
3. 1982 Computer Literacy Project: https://switchgaming.blogspot.com/2013/ ... tml?q=1982