The Stappenmaster Domesday Disc...

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Multiwizard
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The Stappenmaster Domesday Disc...

Post by Multiwizard » Sun Jun 23, 2019 11:34 am

Hi,

as promised my third and weirdest Domesday disc...

I have never seen and heard about this Domesday disc before... :shock:

It's the STAPPENMASTER DOMESDAY disc, see pics below...

I found this double sided disc about a year ago and is in a excellent mint condition. :D

This disc is not just playable in any LD player, some players go mad, others will just pop out the disc tray right away... :shock:

This double sided disc has several "normal" test screens and many weird (video) frequency variable scrambled test screens...

These scrambled screens look a bit like the decoded Videocrypt & D2 mac screens of a satellite dish television channel in the 80's...

Edit: forgot to post this part

The discs wasn't finished, but after 53 minutes I stopped recording:

https://www.youtube.com/watch?v=TffV52YuHIM


If anyone has any further information about this discs please let me know... :?:


Greetings,Wim... :-)

Thanks in advance.

Ps. the A3 scanner wasn't big enough so the edges of the discs are not perfect in the pic... :(
Attachments
StapMas scan converted to small JPGpic.JPG
StapMas label scan converted to small JPGpic.JPG
Last edited by Multiwizard on Sun Jun 23, 2019 12:17 pm, edited 1 time in total.

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danielj
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Re: The Stappenmaster Domesday Disc...

Post by danielj » Sun Jun 23, 2019 12:21 pm

You should lend it to Simon, he's got all the gear to analyse what's actually on it and make an archive copy of it!

d.

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Re: The Stappenmaster Domesday Disc...

Post by Darren Grant » Sun Jun 23, 2019 2:02 pm

It would be worth hooking this up to a TeleText adaptor to see if you get any TeleText data off it.

In an early prototype for domesday they experimented with using TeleText data, inspired by the British Garden Birds Laserdisc title, this was long before all the 35mm slides were collected and turned into video frames. In all likelihood they would have used a simple pattern generator along with a teletext encoder so that there was a valid video signal to impose the teletext on.

There is a possibility that this disc is one of those very early prototypes.

If not the next stage would have been a Philips VLP700 was used with a genlock and a prototype circuit to read the data from the audio channels. It is therefore possible that there is data on the audio channels and the video is just filler for testing, as again the photos would not have been ready.

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simoni
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Re: The Stappenmaster Domesday Disc...

Post by simoni » Sun Jun 23, 2019 4:04 pm

There were no Domesday prototypes that used Teletext as far as all first-person and documented accounts show. The BBC produced the commercial Garden Birds disc which contained teletext as an experiment in interactive video (which was successful) - the success of that was used to prove the early viability of the Domesday project; but much more data was needed, so Philips came up with the LV-ROM format (which is based on EFM and was built around an early version of Philips CD decoding silicon).

Going back to the disc there are a few things that standout. Firstly the patterning on the surface - that is caused by test patterns; second is that the disc doesn't play properly - thirdly it was pressed in the Netherlands. All of that pretty much concludes that it was a Philips internal test disc with the (most likely use) of calibrating or testing the optical assembly of the player (since a complete player cannot play it). It's probably worth translating the Dutch name on the disc also - which means stepping or to step - a common electromechanical term (odd that this wasn't mentioned in the initial post).

All test pressings of the Domesday disc (the contents of which were not developed by Philips) were pressed by PDO in the UK under the supervision of the BBC (check the labels of the test pressings or the information about the release discs). Absolutely no content creation was done in the Netherlands. So there is basically zero chance this disc contains any Domesday project related material. The 'Domesday' refers to the Domesday player (VP415). Also note the disc is CLV not CAV - only the National side 2 (which contains 60 minutes of non-interactive news footage was CLV).

The next step of Domesday prototyping wasn't data in the audio channel; it was the replacement of the analogue audio bandwidth with EFM which is a modulation in itself (rather than manipulation of the audio modulation). The EFM used by the LV-ROM format was to become the basis of CDs (as that is what Philips started developing it for).

There are test pressings with EFM (TP04 has been digitized and documented - it's also the earliest known surviving test-pressing) - they are all Philips PDO (Blackburn UK) pressed - they came quite a bit later. The in between prototype was a RS232 controllable Philips player connected a BBC Model B via the serial port - what would eventually become SCSI based VFS on the, then under-development, BBC Master series machine.

Again, as the disc is CLV and is covered in test patterns that would confuse the playback of a normal player; there is virtually no chance of it containing data of any sort (other than VBI time-codes since only CAV supported frame numbers). The fact it's CLV also precludes it from containing any still images - the basis of the 3 sides of Domesday interactive content which are all CAV.

It's cool that it survives; and it's definitely a bit of Domesday history - but I wouldn't spend too much time trying to extract magical unicorns from it :)

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Re: The Stappenmaster Domesday Disc...

Post by Darren Grant » Sun Jun 23, 2019 8:03 pm

simoni wrote:
Sun Jun 23, 2019 4:04 pm
There were no Domesday prototypes that used Teletext as far as all first-person and documented accounts show.
I must be misremembering then, the original idea was to use Teletext but was determined to be unsuitable. It has been several years since I last thought about any domesday stuff. It seems odd if it is just a calibration disc that they put DOMESDAY on the label instead of VP415 or LV-ROM.
Last edited by Darren Grant on Sun Jun 23, 2019 8:07 pm, edited 1 time in total.

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simoni
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Re: The Stappenmaster Domesday Disc...

Post by simoni » Sun Jun 23, 2019 8:29 pm

The patterning on the surface of the disc and the CLV format are the tells that it's for calibration; there are a number of similar examples of such laserdiscs produced for internal R&D and manufacturing purposes. The VP415 was developed specifically for Domesday, so the label isn't surprising (see the press release below).

As for the history of Domesday, I'm happy to be proven wrong (especially by way of documentation). If anyone finds anything the contrary then I will happily update the information on my website https://www.domesday86.com

On the whole, the Domesday project was an amazing feat in terms of speed; Garden Birds was release in 1982; in 1984 Philips announced the VP415 was to be developed, and in 1986 the whole system was launched.

Here's the VP415 press release: https://www.domesday86.com/wp-content/u ... cement.pdf

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Re: The Stappenmaster Domesday Disc...

Post by Darren Grant » Tue Jun 25, 2019 4:24 pm

I looked back on my notes and Simon you are right, no teletext discs were made. The idea was to use full frame Teletext to store the data on the disk, not just the blanking interval like regular teletext. It was decided that it would not be suitable for the volume of data required for Domesday, the main limitation being that using full frame teletext it would not be possible to store the photo and data in the same frame. As a result no test discs would have been produced and this disc is simply going to be some kind of calibration disc.

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