Abstraction Computer Science and Software Engineering 2014 Project

Abstraction • Removing details • Separation of concerns • Strategy for handling complexity

The Ladder of Abstraction application software for thing in room: pick_up(thing) high-level language COBOL C int register c; 01010010 101011111011 01000101 0111110 en. wikipedia. org/wiki/File: Intel_80486 DX 2_bottom. jpg voltage and current physics http: //en. wikipedia. org/wiki/File: Transistorer. jpg - + + + - bytes and bits Grace Hopper low-level language N P N http: //thelovef orhistory. wor dpress. com/2 011/05/24/ein stein

CPU Follows a Sequence of Instructions • CPU is the Central Processing Unit: one “core” • Our programs are turned into instruction understood by the CPU en. wikipedia. org/wiki/File: E 6750 bs 8. jpg

Typing Code That Makes Sense Closer to Human Language Thankfully, Grace Hopper invented the compiler, a computer program that lets programmers work with more human-readable language. A compiler translates a more human-friendly code into a sequence of assembly language code before the code runs. Grace Hopper called her new language COBOL. She received a B. S. in mathematics from Vassar College and a Master’s and Ph. D. from Harvard. She programmed the Mark I, II, and III computers and was a Rear Admiral in the U. S. Navy. Grace Hopper 1906 -1992