The code computers use to express the digital information they process is called the code?

Its called binary code consist of only 1s and 0s can look anything like this:

111111111

000000000

101010101

110011001

001101010

101010100

001110100

a single one or zero called a bit

a line of ones and zeros are called bytes

1012 bytes is a kilobyte or KB

1012 kilobytes is a megabyte or MB

1012 megabytes is a gigabyte or GB

1012 gigabyte is a terabyte or TB

In speed they are considered in hertz:

Khz

Mhz

Ghz

and in very rare cases Thz