After many weeks grappling with an old programme called LRMI - Linux Real-Mode Interface - on OpenBSD I reached a point at which it issues a call to "i386_vm86". But working code for that appears no longer to be in the OS. I could perhaps persevere, but there is no point, because there must be a simpler way to do what I want - namely - to start with - write a generalized procedure to switch backwards and forwards between real mode and the processor's various protected modes, as well as provide the ability to tinker with the video modes.
I had a look at Barry Kauler's "Puppy Linux" - en.wikipedia.org/wiki/Puppy_linux - which has a good approach - every one is "root" and there are none of those silly log-ins and mountings - but there remain familiar difficulties with the brightness control and the video modes. Just at present I am working through Linux from Scratch (build your own OS - en.wikipedia.org/wiki/Linux_from_Scratch ); instructive in parts, horrifying in others. It takes about a week to work through everything.
But - better than that - I have now also discovered a mainly Russian system called "KolibriOS" - en.wikipedia.org/wiki/KolibriOS - ; a wondrous production commendably written in assembly language. It boots in an instant - and it is all very acceptable in style. I have down-loaded the source and will over the coming weeks examine it and attempt to twist it to my own purposes.
Last Edit: Apr 14, 2014 18:43:32 GMT -5 by Deleted