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Computer Science Praxis 5651 - Master Set

Key Concepts:

Terms in this set (174)

Machine language
The binary system that instructs the computer's basic processing functions. The most dissimilar, also known as lowest-level, language.
Low-level language
A language that is close to machine language.
Assembly Language
ASM: 2nd-generation, low-level programming language - strong correspondence with the architecture's machine language.
Virus
A software program that is written to intentionally do damage and is typically spread and activated by another user's actions.
Worm
A program that is designed to spread from one computer to another, sometimes carrying a payload, sometimes just spreading without doing any additional damage.
Data Types
integer (int), real/float (float), Boolean (bit), composite types (array, record, union, set, object)
Visual Basic
A programming language that was developed by Microsoft as a language to teach beginning programmers how to program computers.
C++
Derived from C language - 3 Principles: encapsulation, inheritance, polymorphism.
HyperText Markup Language
HTML. Using HTML, programmers can embed formatting instructions into a file. The browser then reads the instructions and uses them to display the file on a computer monitor.
System Development Process
Project planning, feasibility study

Systems analysis, requirements definition

Systems design

Implementation

Integration and testing

Acceptance, installation, deployment

Maintenance
Project planning, feasibility study
Establishes a high-level view of the intended project and determines its goals.
Systems analysis, requirements definition
Refines project goals into defined functions and operation of the intended application. Analyzes end-user information needs.
Systems design
Describes desired features and operations in detail, including screen layouts, business rules, process diagrams, pseudocode and other documentation.
Implementation
The real code is written here.
Integration and testing
Brings all the pieces together into a special testing environment, then checks for errors, bugs and interoperability.
Acceptance, installation, deployment
REMOVE -The final stage of initial development, where the software is put into production and runs actual business.
Maintenance
What happens during the rest of the software's life: changes, correction, additions, moves to a different computing platform and more. This, the least glamorous and perhaps most important step of all, goes on seemingly forever.
RJ-45
Standard 8 wire connector (ethernet cord tip)
RJ-11
Standard 4 wire connector (phone cord tip)
Object-Based Programming
Instead of a procedural list of actions, this method is modeled around objects that interact with each other. Classes generate objects and define their structure, like a blueprint. The objects interact with each other to carry out the intent of the computer program.
Interpreter
A language processor which converts a HLL(High-Level Programming Language) program into machine language by converting and executing it line-by-line. If there is any error in any line, it reports it at the same time and program execution cannot resume until the error is rectified.
Compiler
EDIT - Attempts to read all the source code at one time and then convert that code into object code, which can eventually be executed. Some of these programs contain linker programs that can make the object code completely executable.
Debugger
A computer program that is used to test and fix other programs, mainly to solve programming bugs.
Sequential Access Storage
A class of data storage devices that read stored data in a sequence. This is in contrast to random access memory (RAM) where data can be accessed in any order. Usually in the form of magnetic storage.
Random-Access Storage
Allows data items to be accessed (read or written) in almost the same amount of time irrespective of the physical location of data inside the memory.
Direct Access
Secondary storage in which "each physical record has a discrete location and a unique address.
Object
A programming unit consisting of data and methods for interacting with that data.
Class
EDIT - Type of object. Multiple objects may be based on the same lines of written code. All objects based on this code are in the same class.
Instance
A single object from a particular class. An object is an "instance of a class." Where the class is a blueprint, the object is the result.
Variable
a single location in the computer's memory capable of storing one value. Such locations provide temporary storage for multiple types of data (see data types), including numbers and characters
Constant
EDIT -A name that describes a present, unchanging value. It remedies the problems associated with literals, such as their ambiguity of meaning and difficulty to alter in the program.
"AND" or "+" or "&"
REMOVE -documents that contain several keywords
"NOT" or "-" or "!"
REMOVE -documents that contain one keyword but not the other
?
Symbol substituted for an unknown character in a value.
Selection Sort
Finds the smallest element in the array and then places that item at the beginning of the array. The process is then completed for the rest of the array, starting with the next element.
Bubble Sort
REMOVE - Goes through the list and compares every number to the next one. If those two numbers are in the wrong order, it will swap them. It will repeat this process, going back to the beginning every time it finishes, until the list is fully sorted.
Shell Sort
Starts by sorting pairs of elements far apart from each other, then progressively reducing the gap between elements to be compared. Starting with far apart elements can move some out-of-place elements into position faster than a simple nearest neighbor exchange.
Merge Sort
Requires splitting the list into two lists, sorting each of the lists, and then merging the two lists back into one sorted list.
CPU Clock
Measures the number of basic CPU operations per second.
n-bit architecture
Capability to operate on n digit binary numbers in a single machine instruction (ex. 4, 8, 32, 64).
4 GB of Memory
REMOVE - Capability of an address bus with 32 wires - equal to 2 to the power of 32 bytes.
big-endian
"big" end of a number stored first (right to left) - standard used by network routers.
little-endian
"little" end of a number stored first (left to right)- typically used by CPU's.
x86 architecture
CPU architecture first used in the Intel 8086.
Register
The CPU's internal memory cells.
BIOS
Built-in program responsible for loading the computer's basic functionalities - Basic Input/Output System.
Byte
8 digit binary number (8 bits)
Binary Heap
A special type of Binary Search Tree in which parent node is always greater than both children. Find max number: O(1); Search / insert: O(log n).
Tree
Data structure consisting of nodes with exactly one parent (excluding the root) connected by pointers called edges.
Binary Search Tree
A special type of Tree in which parents can have exactly two children - left child nodes < parent; right child nodes > parent.
Linear Data Structures
Array, Linked List, Stack, Queue
Non-Linear Data Structures
Tree, Graph
Greedy Algorithm
An algorithm that picks, at each step, the optimal move (ex. classroom scheduling)
Set
Similar to a list; however, cannot contain duplicate values.
O(2^n)
"Exponential": The algorithm takes twice as long for every new element added.
O(1)
"Constant": Remains constant regardless of the size of the data.
O(log n)
"Logarithmic": The time taken increases with the size of the data set, but not proportionately so (ex. Binary search of a sorted table).
O(n)
"Linear": Increases in proportion to n - 1 item takes 1 sec, 10 items take 10 secs (ex. finding an item in an unsorted list).
O(n log n)
"Linear * Logarithmic": Increases at a multiple of a constant (ex. Merge sort, Quick sort).
O(n^2)
"Quadratic": Increases in proportion to the product of n * n - 1 item takes 1 sec, 10 items takes 100 secs (Bubble sort).
O(c^n)
"Exponential": Increases based on the exponent n of constant c - for 2^n: twice as long for every new element (ex. Traveling Salesman problem).
O(!)
"Factorial": Increases in proportion to the product of all numbers (ex. Traveling Salesman brute force).
Brute Force
Unsorted search starting with the first element. O(!).
Binary Search
Divides sorted array in half, searches remaining half (ex. phone book). O(log n).
Simple Search
Searches a sorted array in order beginning with the first element. O(n).
Breadth-first Search
Searches a graph and finds shortest existing path from A to B (ex.mango seller). O(V + E).
Selection Sort
Array is considered in two parts (sorted, unsorted); select lowest/highest element in unsorted array and bring to starting position (ex. Think "playlist", Radiohead). O(n^2). Requires n-1 passes. Original sort order doesn't matter.
Insertion Sort
Using a marker, swap smaller value elements rightward to correct position and shift unsorted element leftward. O(n^2). Best Case: Already sorted. Worst Case: Reverse order.
Bubble Sort
Works by repeatedly swapping adjacent elements if they are in wrong order. O(n^2). [Verify - Any list of numbers with the length n can be sorted in under n-1 rounds.]
Quicksort
Using "pivots", recursively divides arrays into less and greater than sub-arrays. Fastest for large n. O(n log n) / Worst case: O(n^2) - Pivot is smallest/largest element -> creates arrays of size 1 and n-1.
Merge Sort
A recursive D&C algorithm that divides an array into two halves, calls itself for the two halves and then merges the two sorted halves. O(n log n). Advantage: Original order doesn't matter. Disadvantage: Uses a temporary array as large as original array.
Parts of a loop
Start, Check, Action, Step
Types of Loops
for, while, do while
What type of loop requires a post condition?
Do While
While loop definition
Pretest loop that starts and repeats while a condition is true; ends when false
What is the structure of a For Loop?
for (condition; true; false}
{
code here
}
What type of loop always runs AT LEAST once?
Do While
What is the structure of a do while loop?
int x<-some number
do {set value
do some code
} while (condition)
Which is better, a loop or recursion?
Recursion is more memory efficient but there are things recursion can do that loops cannot. Use a loop when you can.
What are the characteristics of an array?
All entries must be the same data type, of a fixed size, index based
What is a single dimension array?
a weekly pill box
What is a multi-dimensional array?
stacked coke crates
Start of an array index? (What is the first number?)
0
Define Stack
EDIT -Data can only be added or removed from the top
What is PUSH in a stack?
Add a value to the top
What is POP in a stack?
Remove the top element
What is PEEK in a stack?
Look at the top element
What describes a Stack operator?
LIFO (Last in, first out)
What is a queue?
collection of data kept in the order it was collected. You can only add from the back and remove from the front (line at BestBuy)
What describes a queue operator?
FIFO (First in, first out)
What is a head and tail of a queue?
head-what is removed; tail-what is added
Big "O" Notation
Describes the performance or complexity of an algorithm - based on number of operations (growth of n). Describes the worst-case scenario.
O(1)
"Constant time" - fastest, instant access regardless of size (array)
O(n^2)
"Quadratic time" - performance is directly proportional to the square of the size of the input data set (nested): Selection Sort.
O(log n)
"Log time" - divides sets in half: Binary Search
O(n log n)
Fastest sorting algorithm - unsorted (log n) and proportional to the number of elements (n): Quick Sort (pivot), Merge Sort.
What is DHCP?
Process that assigns IP addresses
Primary storage?
RAM
Secondary storage?
hard drive
What is a worm?
sends copies without attachments
What is SMTP?
send and receive email
what is pass by value?
Like a google copy; the original DOES NOT CHANGE
What is pass by reference?
An object points to an object in memory; someone viewing a shared google doc
The best way to use a library of code is to:
access the methods (functions) in the interface
What are the two parts of recursion?
terminate base case and recursive case
Which runs slower, RAM or hard drive?
hard drive
What does email stand for?
electronic mail
VGA
Video Graphics Array - What connector has 15 pins and connects monitor to tower? (old school)
Name two document formats
doc, rtf
What is an IP address format?
four places, separated by dots, all between 0 and 255.
Parts of a computer are connected by
buses
students that learn through physically doing
tactile or kinesthetic
students that learn by watching or taking notes
visual
an example of pair programming
REMOVE - one observes, the other codes
when you start a computer, what runs first?
BIOS
BIOS stands for:
basic input output system
free trial software is called
shareware
How can you ensure that an email sent to a colleague stays private?
share on a school server where a password is required
TXT
What is an unformatted text editor extension?
$
Symbol used to denote an absolute reference in a spreadsheet.
What is software that is burned into the image?
firmware
What does SMTP (send mail to people) really stand for?
simple message transfer protocol
What hampers blind readers using ereaders?
ereaders cannot read symbols or pictures
In a standard database, one row stands for:
a record
USB
How do you connect a digital camera to a computer? (old school).
USB stands for:
universal serial bus
Name the steps in a development cycle.
Analysis, design, Implement, Test, Maintain
Development Models
Waterfall, Incremental, Agile, Spiral, Chaos
Name three design types in development cycle.
top-down, bottom-up, object-oriented
What is object-oriented design?
Contains modules, or pieces, that you create that link together.
Waterfall Method
Development flows in a linear downward direction through the SDLC phases - linear, requirements-heavy, low risk, rigid
Incremental Method
Divided into various builds / development cycles - more flexible, risk-tolerant, cyclical.
Spiral Model
The project is carried out as a series of complete loops that go through most of the SDLC (except maintenance). Each loop produces a 'prototype' of some aspect of the system - high risk.
leaf
How do you connect a digital camera to a computer? (old school)
What distinguishes the root from other nodes?
It has children but no parents.
Backnus Naur form
A formal notation to describe the syntax of a given language. ::= means "is defined as." | is or.
Chaos Method
Unify the best programming methodologies with the best project management techniques - to identify pertinent issues and "always resolve the most important issue first". Characteristics include: pattern-switching and logic gates.
Agile Method
Incremental approach breaks complex projects down into simpler mini-projects: change-tolerant, incremental value, SCRUM.
O(n)
"Linear time" - proportional to the number of operations: Simple Search
O(n!)
"Factorial time" - increases proportionally to the sum of all numbers: Brute Force, Traveling Salesman problem
Big "O" Notation Hierarchy
O(1), O(log n), O(n), O(n log n), O(n^2), O(n!)
Binary Search Tree
Data structure possessing one root node with each node having <= 2 child nodes (left, right). Ordering Property: Left node < root node < all right nodes. Best Case: O(log n), Worst Case: O(n) (unbalanced).
Hash Table
Key-Value lookup
PNG
(Portable Networks Graphic): Lossless compression, BEST for web pages.
GIF
(Graphics Interchange Format): Lossless compression, GOOD for web pages, 8-bit only (<= 256 colors).
TIFF
(Tagged Image File Format): Lossless compression of image and data tags.
BMP
(Bitmap): Lossy raster graphics image file format ("wrapper").
JPG
(Joint Photographic Experts Group): Good for pictures, lossy compression.
Lossless Formats
PNG, GIF, TIFF
Lossy Formats
BMP, JPG
LAN
A computer network that interconnects computers within a limited area - Local Area Network.
WAN
A telecommunications network or computer network that extends over a large geographical distance - Wide Area Network.
OSI
Defines seven abstract layers of networking protocols - Open Systems Interconnection.
IP
blah - Intellectual Property Rights: Copyright Laws, Fair use, Patents, Trademarks
Documentation
blah - Online Help
Support Documentation
Technical-Writing Strategies
Impact of Technology
blah
Equitable Use of Technology
Gender, Ethnicity, Language, Disabilities
Problem-Solving
Design Specification
Top-Down Design
Step-wise refinement
OOP
Visual Organizers
Flowcharts, Schematic drawings
Top-Down Design
Breaks down large projects into steps that are easily managed. Final low-level tasks are easy to implement (a.k.a. Stepwise Refinement)
Bottom-Up Design
Uses predefined and tested modules to help implement the solution. Saves time and effort - don't "reinvent the wheel".
Object-Oriented Design
Is data-centered. Bundles actions and processes with data into a neat package.
Three Principles of OOP
Encapsulation, Inheritance and Polymorphism
HTTP
Set of rules for transferring files on the World Wide Web - Hypertext Transfer Protocol
SMTP
TCP/IP protocol used in sending and receiving e-mail - Simple Mail Transfer Protocol.
TCP/IP
communication protocols used to interconnect network devices on the internet - Transmission Control Protocol / Internet Protocol.
POP
Used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connection - Post Office Protocol
HTML
the standard markup language for creating web pages - Hypertext Markup Language.
UML
A general-purpose modeling language in the field of software engineering - Unified Modelling Language.
Copyright
The exclusive legal right to reproduce, publish, sell, or distribute the matter and form of something.
Fair Use
A legal principle that defines the limitations on the exclusive rights of copyright holders.
Patent
A government license that gives the holder exclusive rights to a process, design or new invention for a designated period of time.
Trademark
Any name, symbol, figure, letter, word, or mark adopted and used by a manufacturer or merchant in order to designate his or her goods and to distinguish them from those manufactured or sold by other
DHCP
A network management protocol used on TCP/IP networks to dynamically assign IP addresses - Dynamic Host Configuration Protocol.
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