EBCDIC is an 8-bit binary code for larger IBMs primarily mainframes in which each byte represent one alphanumeric character or two decimal digits. 256 characters can be coded using EBCDIC.

BCD is a binary coded notation in which each of the decimal digits is expressed as a 8-bit binary numeral. For example in binary coded decimal notation 12 is 0001 0010 as opposed to 1100 in pure binary.

ASCII is a code which converts characters – letters, digits, punctuations and control characters such as Alt, Tab etc – into numeral form. ASCII code is used to represent data internally in micro-computers. ASCII codes are 7 bits and can represent 0 to 127 and extended ASCII are 8 bits that represents 0 to 255.

IBM-1401, CDC-1604 is second generation computer. ICL-2900 is a fourth generation computer. EDSAC is important in the development of computer since it was the first computer to use John von. Neumann’s Stored Program Concept. It used 3000 vacuum tubes and computers with vacuum tubes are of first generation computers.

Transistors were used for second generation computers and integrated circuits in third generation. First generation computers used vacuum tubes and valves as their main electronic component. Vacuum Tubes were invented by Lee DeForest in 1908.