As you learned earlier in the course, your computer can
be reprogrammed to run many different Applications. These application programs are written
in a variety of programming languages - Java, C++, Pascal, etc. However, your computer does not
really "understand" any of these languages. All of the programs that we humans write in some
symbolic "human" language must first be converted to the only language a computer understands -
Machine language is binary code: sequences of zeros and ones, sets of
switches that are off or on, voltages that are low or high, magnetized areas on iron oxide surfaces,
or valleys and peaks burned on plastic disks.
Originally programmers had to write programs in
machine language by throwing switches on a computer console to input sequences of zeros and ones.
Later, programs were written to translate human-friendly (high-level or source) code into
machine-friendly (low-level or object) code. In this chapter you will glimpse, in a simplified way,
how code is translated and executed by your computer. In order to understand how this works you
will know more about binary code and coding schemes.