How assembler has been made ?!

Hello,

I’m trying this days to learn assembly, I’m using tasm, I’m aiming to understand how computer works inside itself in the deep as I can arrive to.May be assembly language used to program some first softwares, may be it used to program DOS, but what’s the language or the way that before the assembly, suppose that we have no language to program, how we can program what we want of the first programs or OS ?

Please help.

I did not find the right solution from the internet.

References:-
How assembler has been made ?! | Computer Help Forums - Free PC Help
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Thanks