There are one or two instances in Brook's computer zoo where he said something like "the mnemonics are our invention, the designer simply used numeric opcode or the character whose code was the opcode", so there where machines for which there wasn't even an assembly language.

Entering programs end debugging at the front panel (for those who haven't done it, it was a way to set up the memory, you set some switch to the address, some other to the value and pressed a button, or another button to read the value) was common far later. Some old timers brag they would still be able to enter the boot code for machines they used extensively.

The difficulty of writing directly machine code and reading programs from memory dump is quite dependent on the machine language, some of them are relatively easy (the hardest part is tracking the addresses), x86 is one of the worse.

There are one or two instances in Brook's computer zoo where he said something like "the mnemonics are our invention, the designer simply used numeric opcode or the character whose code was the opcode", so there where machines for which there wasn't even an assembly language.

Entering programs end debugging at the front panel (for those who haven't done it, it was a way to set up the memory, you set some switches to the address, some others to the value and pressed a button, or another button to read the value) was common far later. Some old timers brag they would still be able to enter the boot code for machines they used extensively.

The difficulty of writing directly machine code and reading programs from memory dump is quite dependent on the machine language, some of them are relatively easy (the hardest part is tracking the addresses), x86 is one of the worse.