1 Week 1: The History of Computing: Software READING: Chapter 1.2

2 2 First Generation ( ) Machine Language The first programs were written in machine language, in which the instructions are written in different sequences of binary numbers (0s and 1s) Programmers had to remember which combination of binary numbers refer to which instruction Time consuming, prone to error

3 3 First Generation ( ) Assembly Language The first artificial programming language – assembly language Used mnemonic codes to represent each machine-language instruction Example: an 8-bit machine code “ ” which causes the CPU to decrement the “B” register was represented in assembly language as “DEC B”

4 4 First Generation ( ) Assembly Language Because every program that is executed on a computer eventually must be in the form of the computer’s machine language, a software called translators was also developed to translate the program written in assembly language into machine code

5 5 Second Generation ( ) High-level Language High-level languages were developed to allow the programmer to write instructions using more English-like statements Examples of high-level languages during this generation: FORTRAN COBOL A program written in high-level languages can be translated and run on any machine that has a translating program called complier Programming statements such as “IF”,“GOTO”, etc. are introduced

6 6 Third & Fourth Generation ( ) Introduction of structured programming, a logical, disciplined approach to programming Examples: C, C++ Making use of block structures such as “for-” and “while-” loops

7 7 Third & Fourth Generation ( ) In the 80s, the OS of Macintosh introduced the concept of the mouse and the point-and-click graphical interface, changing the computer-user interaction drastically High-quality applications software packages also become available Spreadsheets (e.g. Lotus 1-2-3) Word processors (e.g. WordPerfect) Database management (e.g. dBase IV)

8 8 Fifth Generation (> 1990) Introduction of Microsoft Office: word processors, spreadsheet programs, database programs, and other application programs were bundled together into super packages Introduction of World Wide Web (www): allows easy global communication British computer scientist Tim Berners created a set of technical rules intended for a universal Internet document center. With these rules, he created HTML, a language for formatting documents, and a text-only browser, a program that that allows a user to access information from websites worldwide