Damn, damn Bill. Within the last 24 hours - while looking for something unrelated - I came across something about "configurable BIOS" and made a mental note to investigate further because of the possibilities which interested me for the future.

I'm thinking along somewhat similar lines as yourself, but quite different [I know that doesn't make sense]

Thanks to you Bill, I'm now going to spend the remainder of the day torturing my already frazzled brain to recollect what and where?

I'm trying to build a better mousetrap - as the saying goes.

"configurable BIOS"

Yes! That sounds along the lines of what I was thinking about. If you come across that info I'd be very happy to see it (sorry about the extra brain frazzling).

I was looking at various motherboard BIOS and realizing that there's not much you can do to change a lot there. I'm thinking that I'd need a motherboard that supported the sort of BIOS I wanted. It's not like an OS where you can install just about anything you want there.

While not directly related, here is an interesting topic to consider when looking for motherboard features.

Intel® Active Management Technology

[intel.com.au ]
One such motherboard [among many] which has this feature is the ASRock Q87M vPro

My broad goal, in the broadest sense is to ideally have a system where...

My Desktop, my laptop, my tablet [if I had one] had a very basic OS [even Windows, maybe even DOS] and any of them can connect to my LAN. On that LAN they can then connect to any OS of choice on drive #1 residing on the LAN. Sort of like a NAS.

Once up and running on that chosen OS - all compatible programs, program data, user files are accessed from drive #2. Drive #1 has no programs. Years ago of rebuilding/clean builds of Windows OS where all your programs, user files, program data are wiped out cured me of ever doing that again.

On the same network accessible to all machines are to be drives #3, #4 .... to infinity where you not only have precious record files, data files, backups of backups, music, videos, films whatever data you normally love and store.

If you have hardware crashes? As I have had [again] many recently

Jump to another device, continue on working as I am now, and maybe repair the broken machine remotely when time permits. As the man once said:

"Given time and money, anything is possible"

This is all now being written right now on my dirt cheap Laptop, connected to programs, data etc. living on a 1TB portable USB drive where a copy of all critical programs/browsers/profiles/user data were backed up from drives C, D, E of a now dead Desktop PC which also has similar backups on external drive J.

PC being the one which gave intermittent signs of problems for weeks, yet every known testing tool I had couldn't identify the problem, even using a different mobo. Memory passed all tests, CPU passed every Intel integrity test with their Intel Processor Integrity Tool... There is no known motherboard test as such.

HWiNFO64 and CPUID-HWMonitor PRO both produced lengthy reports over time, constantly monitoring and showing nothing untoward.

Obviously all my procedures from the past have once again paid off - I want a more refined [cheap] system.

The search for such a bios is grand, and I'm all for it.

Would I do it? Probably not. It's the old "eggs in one basket" problem for me. I do agree that having data/programs in separate areas is superior to all in one (and have been doing that for years). Even so, that boot drive (however accessed) has thread pointers to programs and data embedded there so that when that drive fails, that data is not accessible until re-established by a new program load unless, of course, mirrored backups are maintained.

But I do like the IDEA of all in one!

I wonder if that Intel® Active Management Technology is another term for the Intel Management Engine.
That's a microcontroller that has direct access to everything in a computer. All Intel chips these days have them, but they're a real hacking vector from what I've read. Maybe that's a newer version.

Would I do it? Probably not. It's the old "eggs in one basket" problem for me.

You're putting more eggs into a basket if you dual boot off a single partitioned HDD. This method separates the risk that a Windows or Linux distro does something bad to that one main disk that contains all your eggs. Backups would of course be a big part of anything I build. This hardware OS separation somehow seems more robust...and refined.