Introduction to Computer Science CIS 111 06 August 28, 2007 David Goldschmidt, Ph.D. Computer Science The College of Saint Rose

Hardware (i) Hardware is physical equipment “flat-panel” “desktop” “standard” “laptop” or “notebook” “tower”

Hardware (ii) Tablet PCs combine laptop and PDA features

Hardware (iii) Tablet PCs combine laptop and PDA features

Portable Flash Memory Drives Looks like another hard drive in “My Computer” Excellent for portability and for backing stuff up

Software Software is a computer program, which “runs” on hardware Hardware does nothing without software

Application Software Application software is software designed to perform specific tasks Examples: Word processing Spreadsheets/databases Presentations Communications Information Access

Please print your tent-card In-Class Exercise Use Microsoft Word to create a “tent-card” that displays your first name and the first letter of your last name Use a big font (nothing too fancy) Set the page into “landscape” mode Center your name Fold here and here.... Dr. G Please print your tent-card and bring it to class!

Numbering Systems We count using our fingers.... Base 10: Computers count using binary digits or bits.... Base 2: 009 008 012 013 007 011 010 000 006 002 001 003 004 005 00000110 00000111 00001000 00000101 00000000 00000001 00000010 00000011 00000100

Base Conversion A byte is a grouping of 8 bits Convert an unsigned binary number (11011001) to decimal (base 10): What about negative integers? unsigned byte ranges from 0 to 255 1 2 4 8 16 32 64 128 base 10 value 1 128 64 + 16 + 8 + 1 + = 217

Two’s Complement Conversion from binary to decimal is identical, except the leftmost bit always has a negative weight -128 64 32 16 8 4 2 1 base 10 value = -39 + + + + two’s complement byte ranges from -128 to 127