Thanx Mark for super quick reply... But, what about the machine language? how to write that using binary code? How did the people who first got the computer up and running write programs? I am pretty sure they did not hav machine language in the beginning... Can we write a simple machine language using binary code ourselves?
The "machine language" is the binary code that the computer executes. "Assembly language" is the human programming language that corresponds to the machine language.
The earliest computers didn't use machine language; they were programmed with plugboards. See http://en.wikipedia.org/wiki/Plugboard
for some pictures of a plugboard for an IBM 402 Accounting Machine.
Later, when stored program computers were developed, one of the common ways to enter the binary codes was with front panel switches. Here's a video of loading a short program into a PDP-8
(an early mini-computer).
Normally one would enter a slightly longer program--a dozen or so instructions--called a "bootstrap" that would then read the operating system from the system's paper tape reader.
On an early mainframe I used, you would type the bootstrap program in with the console typewriter. The bootstrap would load the first file form the system tape, which was a slightly more sophisticated loader that would load the OS from the system tape. If I remember correctly, the bootstrap was "I0H01000U0001000" (that's two 48-bit instructions).