Computer Science Chapters 1-4
Fixed-Sized Numbers
0 through 49 represent 0 through 49 50 through 99 represent -50 thought -1
Base 16 digits
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F
HiColor
16 bit color depth
Unicode Character set
16 bits per character
Machine Language
1st Generation Software: Computer programs written in binary (1s and 0s)
Programmer Changes
1st Generation Software: Programmers are divided into Application programmers and systems programmers
Assembly Languages and Translators
1st Generation Software: Programs written using Mnemonics, which were translated into machine language
Vacuum Tubes
1st Generation: Large, not very reliable, generated a lot of heat
Magnetic Drum
1st Generation: Memory device that rotated under a read/write head
Card Readers- Magnetic Tape Drives
1st generation: Sequential auxiliary storage devices
TrueColor
24 bit color depth
High-level Languages
2nd Generation Software: English-like statements that make programming easier: Fortran, COBOL, Lisp
Magnetic Disks
2nd Generation: Replaced magnetic tape, data can be accessed directly
Transistor (generation)
2nd generation: Replaced vacuum tube, fast, small, durable, cheap
Magnetic Cores
2nd generation: Replaces magnetic drums, information available instantly
Separation between Users and Hardware
3rd Generation Software: Computer programmers write programs to be used by general public
Transistor
3rd Generation: Now used for memory construction
Integrated Circuits
3rd Generation: Replaced circuit boards, smaller, cheaper, faster, more reliable
Terminal
3rd Generation: an input/output device with a keyboard and screen
Typical Application packages
4th Generation Software: Spreadsheets, Word processors, Database management systems
Structured Programming
4th Generation Software: a logical, disciplined approach to programming: Pascal and C++
Large-scale Integration
4th Generation: Great advances in chip technology
Computing Skills
5th Generation Software: Algorithmic, Representation, Programming, Design
World Wide Web
5th Generation Software: Allows easy global communication through the Internet
Object-Oriented Design
5th Generation Software: Bases on a hierarchy of data object (Java)
Microsoft
5th Generation Software: Windows operating system and other Microsoft application programs dominate the market
How many computer character sets existed in 1960?
9
Positional Notation
943 = 9 x X^2 + 4 x X^1 + 3 x X^0
Information
Data that has been organized or processed in a useful manner
How to convert base 10 to other bases
Divide the decimal number by the new base, make the reminder the next digit to the left in the answer, replace the decimal number with the quotient.
Harvard Mark I, ENIAC, UNIVAC I
Early computers launch new era in mathematics, physics, engineering and economics
Networking
Ethernet connects small computers to share resources File servers connect PCs in the late 1980s
Ada Lovelace
First Programmer, the loop (series of instructions the repeat) Edited Babbage's work
Blaise Pascal
French mathematic that built and sold the first gear-driven mechanical machine that did addition and subtration
JPEG
Joint Photographic Experts Group
Video Codec
Methods used to shrink the size of a movie (Lossy)
Temporal Compression
Movie compression technique based on differences between consecutive frames
Spatial Compression
Movie compression technique based on the same compression techniques used for still images
Ten's Complement
Negative (I) = 10^k - I, where k is the number of digits
What three sets can pre-school children identify?
One, two or three (many)
PNG
Portable Network Graphics
Jacquard
Proposed that a punched card be used for counting the census
Reclock
Reasserting an original digital signal before to much digression occurs
Data Compression
Reducing the amount of space needed to store a piece of data or the bandwidth to transmit it
Run-Length Encoding
Replacing a long series of a repeated character with a count of the repetition flag*, repeating value, number of times
Quantization
Represent the voltage as a number using a finite number of bits
Vector Graphics
Representation of an image in terms of lines and shapes
How does an abacus work?
The beads at the top are 5 and the ones at the bottom are 1. the beads away from the middle don't count.
What concept makes positional notation possible?
The concept of zero.
Hardware
The physical elements of a computing system (printer, circuit boards, wires, keyboard...)
Software
The programs that provide the instructions for a computer to execute
Compression ratio
The size of the compressed data divided by the size of the uncompressed data
Alan Turning
Turing Machine, Artificial Intelligence Testing
Huffman Encoding
Using a viable length binary string to represent a character so that frequently used characters have short codes
binary Subtraction
When you borrow, you borrow a 2.
Natural Numbers
Zero and any number obtained by repeatedly adding one to it.
Binary Digits
a digit in the binary number system, a 0 or 1
Words
a group of one or more bytes; the number of bits in a word is the word length of the computer
Integers
a natural number, a negative number
Overflow
a situation where a calculated value cannot fit into the number of digits reserved for it
Rational Numbers
an integer or the quotient of two integers
Data
basic values or facts
Bit
binary digit
Base
determines the number of different digit symbols (numerals) and the values of digit positions
Pixels
dots of color in an image (or display device)
Byte
eight binary digits
GIF
indexed color
Charles Babbage
invented the Analytical Engine (had to do with memory)
Resolution
number of pixels in an image
Sampling
periodically measure the voltage
Keyword Encoding
replacing a frequently used word with a single character
Multimedia
several different media types (numbers, text, audio, images and graphics, video)
Floating Point
sign * mantissa * 10^exp
Lossy Compression
some information may be lost in the process of compression
Rastor Graphics
storage image information pixel by pixel
Color depth
the amount of data that is used to represent a color
Lossless Compression
the data can be retrieved without any loss of original information
Bandwidth
the number of bits or bytes that can be transmitted from one place to another in a fixed amount of time
how does bi-quinary work?
uses 7 lights to represent the 10 decimal digits. (like the abacus)
Pulse-code modulation
variation in a signal that jumps sharply between two extremes
Bob Bemer
Active in programming languages. Best known for his work on the ASCII computer code on 8-bit PCs today. Received the IEEE Computer Society's Computer Pioneer Award.
Byron
Ada Lovelace's father
Grace Murray Hooper
Admiral of the US Navy. she used wire to discover the nanosecond.
ASCII
America Standard Code for Information Interchange started with 7 bits and later extended to 8 bits
Scientific Notion
An alternative floating-point representation. 12001.32708 is 1.200132708E+4 (E+4 is how computers display x10^4)
Abacus
An early device to record numeric values
Audio Information is a *blank* representation
Analog
Hollerith
Associated with IBM
Analog Data
A continuous representation of data
Digital Data
A discrete representation of data, by breaking the information up into separate elements
Character set
A list of characters and the codes used to represent each one
Abstraction
A mental model that removes complex details
BMP
Bitmap
Digitize
Breaking data into discrete pieces
Leibniz
Built the first mechanical machine that did addition, subornation, multiplication and division
Parellel Computing
Computers rely on interconnected central processing and/or memory units that increase processing speed
What happened between 10/24/02 and 10/26/02 to guests of Holiday Inn, Holiday Inn Express or Crown Plaza?
Guessed where charged 100 times what they owed because a credit-processing error resulted in the decimal points being dropped.
Layers of Computing
Information, Hardware, Programming, Operating Systems, Applications, Communications
ARPANET and LANs
Internet
Joseph Jacquard
Jacquard's Loom, the punched card
