Fubar 2019 > Searching for error in obscure or obsolete operating systems (part two) Legacy OS 2017

Legacy OS 2 Demonstration

These are the specs of the computer used to make the videos in this part of the presentation - the important point to note is the agp Ati HD 3650, when i first discovered this particular series of errors I suspected it was the card and the way that xorg configuration misread the card type and set it up as a different type and that this error was only available using this card and a pci-e radeon x300 se ( Dell oem card found in some of their computers circa 2005-6) but I've recently found that this error is reproducible even without these cards if you select xvesa as the graphics driver and not xorg - otherwise if the xorg configuration routine detects the card correctly these errors do not occur .

Computer specs these videos were made on

So , this is legacy os starting up  to the point where you have to choose xorg or xvesa ( xorg is the basic display manager in linux which deals with the GUI , keyboard, mouse, size of screen etc - xvesa is a fallback mode which enables  you to run a graphical display as opposed to command line if xorg fails to detect what your graphic card is )

Legacy OS 2017 start up sequence

If you choose xorg and 24 bit you will get normal colour 16bit will sometimes give more interesting effects . Legacy OS comes with various video players such as VLC and smplayer so at first I played back a file that I'd downloaded from archive.org ( The cabinet of Dr Caligari - I'd been intending to work on a datamoshed version of it as I love it as a film and wanted to see what I could do with it ) - so first off I opened it in VlC 

Dr Caligari played in VLC in Legacy OS 2 

There is some artifacting ie the vertical lines but nothing out of the ordinary, I'd noticed flicking through the start menu that there was also a player I hadn't come across before, so thought okay lets try that, and suddenly something completely different started to happen.

Dr caligari playback via quickplay on legcay OS 2.

This is what happens when you play the same file encoded to the snow codec – each different file format gives different artifacts and result – this without hex editing , sonification or messing with the file in any way.  You can find the full final version of this here, on my PeerTube channel, it's a mix of techniques with this technique as its base 

 

 Dr Caligari encoded to snow, playback in quickplay (24 bit xorg)

If we play a file encoded to ZLIB things get even more interesting. So far this flaw seems  to work best with black and white films.

Pandoras box starring Louise brooks encoded to Zlib playback in quickplay

If we exit back to the command line ( ctrl alt backspace) and reconfigure xorg to work with 16 bit colour we can achieve different and sometimes more interesting renders of the files .

Dr Caligari played in quickplay as before but 16bit xorg 

Or in this next video ( The Hitch hiker - a great and dark film again sourced from archive.org ) there are beautiful areas of banding and lines , interestingly if you maximise the screen the video plays normally , return it to original size when opened and the glitching reappears - a lot of the detail that I see on the screen in real life is being lost in the capture process though as I'm using a cheap vga to composite adaptor which doesnt do justice to whats happening on the screen.

The Hitch Hiker - playback in quickplay 16bit xorg

Now , using xvidcap you can record this from within the operating system – some errors you can , some you can't .This will work with pretty much any file that it can read , but with varying degrees of usefulness for example below Linnea Quigleys 'Horror workout'  – some files just break down into a horrible mush of distortion which is unattractive ( I like to retain some readability in the files and work I create).

Linnea Quigley ' Horror work out' quickplay playback, 16 bit xorg.

Now at first I discovered that this fault could only be replicated using an Ati Hd 3650 agp card or a pci-e radeon x300se ( an oem card that dell put in some of their computers circa 2005-6) but I’ve recently discovered that if you select xvesa as the driver during xorgwizard setup rather than xorg you can achieve the same effect on any agp , pci-e or onboard graphics card which does extend the range of equipment that I can use considerably .

so what exactly is happening here ? What I think is happening is that the Ati card is being recognised by the xorg server but as some other model and that when it writes the configuration after set up the xserver treats the card as this older model, this could be an area of research for the future , what I suspect might also be happening is that the kernel is too old ( 2.6.18.1) to have the correct kernel module for this particular card or it misassigns the model – as the architecture of older Ati cards is roughly similar it works but not correctly , which may explain the lines on playback in vlc – but this doesnt explain everything . I’m open to suggestions as I don’t have the technical knowledge to work this out . 

In the next post I will be dealing with a sister distribution to legacy os 2017 , legacy os mini and what I like to call xorg poisoning. 

Part three https://crash-stop.blogspot.com/2019/10/fubar-2019-searching-for-error-in_30.html