Computer Science Final
Terms
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- Analytical Engine
- Babbage's dream machine
- Babbage
- Father of Computers
- Difference Engine
- automated mathematical tables accurate to 31 decimal places. Invented by Babbage
- Hollerith
- created a tabulating machine for the census
- Jacquard Loom
- the first example of "stored information". It was able to follow a pattern of punch cards
- Pascal
- invented a calculating machine to help his father who was a tax collector
- Pascaline
- Pascal's mechanical device that used gears and wheels to perform addition and subtraction
- Second Generation
- replaced vacuum tubes with transistors. Faster, smaller, more reliable
- Tabulating Machine
- electrical punch cards and clocks made the census take three months instead of ten years
- Antanasoff-Berry Computer
- technically the first digital computer (1939)
- Colussus
- 1943: first fully electronic computer 5000 characters per second.
- ENIAC
- competes for the first digital computer title: 500 times
- Harvard Mark I
- 1944: first automatic elctromechanical calculator
- Computer generation
- groups computers in terms of technology age
- First Generation
- used a lot of energy, were very large. (only used by big corporations or military)
- Third Generation
- 1965-70: integrated circuits instead of transistors. Smaller
- Fourth Generation
- 1970-1980: Large Scale Integration/Very Large Scale Integration. Increased power, reduced price and size
- Fifth Generation
- Current generation: parallel processing, artificial intelligence
- Supercomputer
- first s.c. Cray-1. Fastest type of computer used for massive amounts of math calculations
- Mainframe
- large and powerful: allow many people to be connected at once
- Special Purpose Computers
- Used to work on a specific and restrictive set of problems
- Embedded Computers
- type of special purpose computer built into a larger device: microwave or pop machine
- clockspeed and word size
- determines the speed of the processor. Clockspeed has one pulse per new step in processing. Word size is how many bits a processor can manipulate at one time
- MegaHertz and GigaHertz
- clockspeed is measured in these. This means either millions or billions of clock cycles per second
- Arithmetic Logic Unit and Control Unit
- These make up the CPU: ALU takes care of logic and arithmetic and CU send instructions to all parts of the computer
- primary storage
- memory on your computer that can be quickly retrieved.
- secondary storage
- disks, CD
- RAM
- primary storage. THe computers memory storage. Memory is erased when the computer is turned off (volatile)
- operating system
- in charge of all of the operations (starting the computer, communication, memory management)
- GUI
- graphical user interface. Uses icons to represent programs and files.
- pixels
- tiny colored dots organized in rows and columns
- resolution
- measures how many pixels it contains
- bitmap
- stored on a pixel by pixel basis
- object-oriented
- stores instructions about what is drawn instead of pixels. (shapes)
- tweening
- animators draw key frames and then are able to generate in between frames
- database
- stores large amounts of information in an organized fashion
- SQL
- Structured Query Language. Language that the computer can understand our queries
- Telnet
- allows users to log into remote computers
- bandwidth
- amount of information that can be transmitted in a given amount of time
- Intranets
- intra-organizational networks for email, file transfer for members of the organizations
- HTTP Daemon
- receives requests and sends out corresponding webpages to whomever requested it.
- Synchronous communication
- Instant messages, real time
- Asynchronous communication
- not real time: emails
- Pseudocode
- mixture of English and computer language
- Sequence control structure
- instructions are executed in a sequence
- Selection Control Structure
- If____ then___ else____
- Repetition Control Structure
- While____ is true do this
- Binary language
- a sequence of 1s and 0s that a machine can understand
- Assembly Language
- low-level programming one step above binary; uses short English-like codes
- High-level programming
- COBOL, FORTRAN, BASIC;easier for humans to understand, must be translated to Machine language
- Interpreters
- translate a program one line at a time
- Compilers
- translate an entire program at a time
- Sniffer program
- capture info as it travels through the internet
- backdoors
- anyone with knowledge of backdoor or password can access/modify info
- cyber vandalism
- replaces a website's content with their own
- spoofing
- pretend to be someone you're not
- Accessibility
- data delays and denials; makes the website seem down or slow
- denial of service
- try to make sure that requests never meet their destination
- narrowcasting
- newscasts customized to interests of different groups of people
- pointcasting
- personalized newscast for one individual