Indeed, ‘bootstrapping’ has broadened out as a term to encompass any sort of process where you start something from nothing - like ‘bootstrapping civilisation’ after an catastrophe, for example - or any kind of from-scratch creation of something - particularly if that something is what would be the ideal starting point - for example to build a lathe, it would help if you could use a lathe to manufacture some of the parts for the lathe - so building the first lathe (without the benefit of an existing lathe) is a bootstrapping process.
But that’s not the only use of the term in computing. @QMatic had it right, booting a computer is shortening of bootstrapping.
The term comes from the early days (1950-60s) of computing. Those primitive computers did not start up the operating system automatically on powerup. Instead, a (hopefully) short program needed to be toggled into the computer in binary using switches on the front of the computer. That program would read the paper tape drive and load a program (the operating system) from that to the computer. These computers often only had maybe 4 or 8 K of main memory.
This form of booting went away when someone came up with Read-Only Memory. On powerup, microprocessors begin executing code at address zero and the ROM was hardwired to be at that address. Burn the startup program into the ROM and it’ll load the operating system from the disk drive.
CDC machines had a boot ROM built out of large toggle switches.
http://www.retrocmp.com/tools/pdp11gui/macro-11-source/37-decnet/64-boot-roms
I have a boot ROM from a DEC PDP-11 that is a card filled with diodes. One diode per bit.
As I understood, it was that an extremely simple program loads a simple program which loads the more sophisticated program - so a chain that eventually gets the whole thing up and running. The sequence was called bootstrapping.
When loading, for example off a disk or paper tape - the controller etc. did not do anything fancy - it defaulted to zero location. So the simplest program was “load the first X bytes you get off the first device into memory location starting at zero, then after X bytes are loaded, jump to zero and execute.” That program was a bit more sophisticated, could read file names and follow the chain of file sectors to load the actual program and then start running it, which loaded all the services etc. and so on until all the components of the OS were loaded.
This is why disks have a “boot sector” the very outside sector zero-track zero, if they are used to start a computer; and the first files in the root folder had to be the OS starter, etc.
It was analogous to “lifting by the bootstraps” because with almost no outside help, an incredibly simple program eventually got a very sophisticated one going - sort of like “lifting yourself up without intervention from the outside” the metaphor of lifting by bootstraps, an impossible task that would involve great effort. Unless you were Wiley Coyote.
Yes. But in the early, small memory, computers, the ones that only had 4K of memory, they didn’t really need all those steps, because they didn’t require a sophisticated operating system. As computers got bigger and more complicated, those more sophisticated operating systems were required. So the boot sequence got more complicated.
And them hobby/home computers replicated the evolutionary path. I entered a program in a computer once with the switches. Once…
It’s unfortunate that etymology site doesn’t appear to actually name the source. Wiktionary, suggests an origin of 1834 or earlier:
https://en.wiktionary.org/wiki/pull_oneself_up_by_one's_bootstraps
There is a cite for that at bottom. Maybe the cite itself is inaccurate, but it does seem a bit backwards to think something would go from an obscure physics textbook (as I would assume that even today all physics textbooks would be: obscure) and into popular speech, rather than the other way around.
However, the main thrust appears to be the same: it originated initially as a known absurdity and impossibility, contrary to a basic understanding of how the world works.