The steps (and the way I represented them) are anyway a simplification.
In my mental map the things in parenthesis mean that - as an example - in:
In other words, in "plain", single boot installs:
BIOS->MBR->PBR->NTLDR->(BOOT.INI)->NTDETECT.COM->"Switch"->Other files->OS booted
The BOOT.INI has not an actual use in the booting, since it contains a single entry (and BTW if you installed to First Active partition of first disk in a directory named \WINNT\ - up to 2K - or \WINDOWS\ -XP and 2003 - you can even remove BOOT.INI alltogether).
it's the same, about different mental maps, it is a graphically awful (I do suck at graphics) representation of a "tree", the fact that some "branches" are in the same column doesn't really mean that all items in the same column are in the same category.
Please specify in the top row what was on your mind. For example, I can figure out that the second column is "type of medium", is the 3rd "type of emulation", ...? I can see that it is a classification of some kind, but I can't make out how it is classified.
When I get that, I will make a mind map of it. That illustrates this kind of concept in less space and is more readable. As soon as you're finished of course.
It should look more like a genealogy tree (but in a genealogy tree you have generations as "columns"), this tree is more like a real tree, where branches not necessarily sprout at exactly the same height .....
...my idea is more like this:
I will review the other suggestions.
I put the ">=7.x" because grub4dos could directly chainload only those IO.SYS, last time I checked.
(and then we would go for the distinctions and similarities with IBM DOS and it's files: IBMBIO.COM vs. IO.SYS and between IBMDOS.COM vs. MSDOS.SYS .... the idea was to make a simplified "concepts in a nutshell" and NOT a treatise on how every OS in the world boots and works )
For the record there are also another TWO distinctions between DOSes <7.x:
- The kernel is actually TWO files, IO.SYS and MSDOS.SYS AND IO.SYS must be first file in the filesystem (compare with BOOTPART usage and commands)
- The ONLY filesystems supported are FAT12 and FAT16
- The kernel is "monolithic" (MSDOS.SYS is just a ".ini" file) and there is no *NEED* for IO.SYS to be the first file in the filesystem (use anyway some common sense, you cannot put it in a very high address of it on "BIG" drives)
- Filesystems supported include, besides FAT12 and FAT16 also FAT32
Maybe I expressed myself wrongly.
The PBR "normal" boot code loads one (or more) programs.
In the case of DOS (still >=7.x) and of FreeDOS, it loads directly the kernel.
In most other OSes it loads a loader, that later loads the kernel.
What I was tryng to convey is that in DOS loader and kernel are the same single file.
The above is the ONLY distinction I wanted to point out, there are MANY more limitations and small differences, but again, the idea was to make a quick "reader's digest", if you really want to know the whole story, then you'll have to read many, many books and articles and learn a lot of more things.