Computer Science CS 141 Texas

local variables

A local variable is a variable which is either a variable declared within the function or is an argument passed to a function. As you may have encountered in your programming, if we declare variables in a function then we can only use them within that function.

IEEE 802.11

Describes all kinds of wireless network connections

DNS

Domain Name System is the process that converts a web address (www.domain.com) to an IP address.(192.168.2173)

DDR-SDRAM

Double-data rate synchronous dynamic RAM is capable of speeds in the megahertz and is common to PCs and MACs.

DHCP

Dynamic Host Configuration Protocol runs on the server and contains the list of valid IP addresses for the network.

Spiral Development Model

In each cycle, planning, modeling, construction, and deployment occur. Risk analysis at each step.

Rich Text Format

The Rich Text Format (often abbreviated RTF) is a proprietary document file format with published specification developed by Microsoft Corporation from 1987 until 2008 for cross-platform document interchange with Microsoft products. Most word processors are able to read and write some versions of RTF.

object

locations where information is stored, stored in the attributes of the object, the object is an instance of a class

full tree

no empty spaces to the right

ROM

read only memory, Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware, BIOS lives here

Ctrl - S

saves your document in MS products

contiguous memory

side by side

hyper-threading technology

simulation of two processors

virus

software written to intentionally do damage and is spread and activated by a user's actions

cache

special memory on motherboard used for frequently accessed instructions

coax cable

standard cables for cable tv, solid copper wire

Insertion Sort

start at second card in the list, shifting and inserting into the best position, always looking for best place in list for next card, Best Case O(N) Average Case O(N*N) Worst Case O(N*N)

method call

statement in body of program that activates or executes a procedure, function, or method

microsoft visual basic

teaching programming language

boolean data type

0 or 1, true or false

Huffman encoding

A particular type of optimal prefix code that is commonly used for lossless data compression. Assign binary codes to symbols that reduces the overall number of bits used to encode a typical string of those symbols.

Library of program code

A software library generally consists of pre-written code, classes, procedures, scripts, configuration data and more. Typically, a developer might manually add a software library to a program to achieve more functionality or to automate a process without writing code for it. For example, when developing a mathematical program or application, a developer may add a mathematics software library to the program to eliminate the need for writing complex functions. All of the available functions within a software library can just be called/used within the program body without defining them explicitly. Similarly, a compiler might automatically add a related software library to a program on run time. Libraries are accessed by a method or function using the interface.

Stack

A stack is an abstract data type that serves as a collection of elements, with two principal operations: push, which adds an element to the collection, and pop, which removes the most recently added element that was not yet removed. The order in which elements come off a stack gives rise to its alternative name, LIFO (for last in, first out). Additionally, a peek operation may give access to the top without modifying the stack.

ASCII

ASCII encodes 128 specified characters into seven-bit integers. The characters encoded are numbers 0 to 9, lowercase letters a to z, uppercase letters A to Z, basic punctuation symbols, control codes that originated with teletype machines, and a space. For example, lowercase j would become binary 1101010 and decimal 106. ASCII includes definitions for 128 characters: 33 are non-printing control characters (many now obsolete)[9] that affect how text and space are processed[10] and 95 printable characters, including the space (which is considered an invisible graphic. binary code for microprocessors

ACM

Association of Computing Machinery develops and expands the knowledge in computers.

CSS

Cascading Style Sheets allow the designers to use the HTML tags of the Internet to describe the content of the tags.

parameters passed by value

Changes to the formal parameters inside the method or function call do not affect the actual parameter passed by value or original data

CRA

Computing Research Association that seeks to strengthen research and advance education in computers and related fields.

DRAM

Dynamic RAM must be refreshed regularly by the CPU or it will lose some of its data.

Big-endian

Endianness refers to the order of the bytes comprising a digital word in computer memory. It also describes the order of byte transmission over a digital link. Words may be represented in big-endian or little-endian format. When storing a word in big-endian format the most significant byte, which is the byte containing the most significant bit, is stored first and the following bytes are stored in decreasing significance order with the least significant byte, which is the byte containing the least significant bit, thus being stored at last place.

queue

FIFO data structure similar to a stack, new elements are added to the back of the queue, like a waiting line Enqueue - push a value at the back of the queue Dequeue - remove a value at the front of the queue Peek - look at the value at the front of the queue

SDRAM

Faster than DRAM, controlled by the system clock.

FTP

File Transfer Protocol a method to move files over any type of network.

binary heap sort

Heap sort is a comparison based sorting technique based on Binary Heap data structure. It is similar to selection sort where we first find the maximum element and place the maximum element at the end. We repeat the same process for remaining element. Every parent is smaller than both of its children.

HTML

Hypertext Markup Language, a standardized system for tagging text files to achieve font, color, graphic, and hyperlink effects on World Wide Web pages, not able to make calculations

Global variablesS

In computer programming, a global variable is a variable with global scope, meaning that it is visible (hence accessible) throughout the program, unless shadowed. The set of all global variables is known as the global environment or global state. Global variables should be used sparingly. They are dangerous because they can be written to from anywhere. Overuse of globals can make isolating bugs

Array

In computer science, an array type is a data type that is meant to describe a collection of elements (values or variables), each selected by one or more indices (identifying keys) that can be computed at run time by the program, memory is static, once an array size is declared it cannot be changed, contiguous memory

Selection Sort

In computer science, selection sort is a sorting algorithm, specifically an in-place comparison sort. It has O(n2) time complexity, making it inefficient on large lists, and generally performs worse than the similar insertion sort. Selection sort is noted for its simplicity, and it has performance advantages over more complicated algorithms in certain situations, particularly where auxiliary memory is limited. The algorithm divides the input list into two parts: the sublist of items already sorted, which is built up from left to right at the front (left) of the list, and the sublist of items remaining to be sorted that occupy the rest of the list. Initially, the sorted sublist is empty and the unsorted sublist is the entire input list. The algorithm proceeds by finding the smallest (or largest, depending on sorting order) element in the unsorted sublist, exchanging (swapping) it with the leftmost unsorted element (putting it in sorted order), and moving the sublist boundaries one element to the right

graph

In fact there are only two, nodes and edges. A node (or vertex) is a discrete position in the graph. An edge (or connection) is a link between two vertices that can be either directed or undirected and may have a cost associated with it. An undirected edge means that there is no restriction on the direction you can travel along the edge. So for example, if there were an undirected edge from A to B you could move from A to B or from B to A. A directed edge only allows travel in one direction, so if there were a directed edge from A to B you could travel from A to B, but not from B to A. An easy way to think about edges and vertices is that edges are a function of two vertices that returns a cost. We will see an example of this methodology in a second.

Sequential file

In order to locate the desired data, sequential files must be read starting at the beginning of the file. Sequential access means that a group of elements (such as data in a memory array or a disk file or on magnetic tape data storage) is accessed in a predetermined, ordered sequence. Sequential access is sometimes the only way of accessing the data, for example if it is on a tape

Array Index

Indicates position in array. 0 index based array[0] is the first element

IEEE

Institute of Electrical and Electronics Engineers

Array length

Integer value that indicates the number of elements in an array. list.length or len(list)

Exception Handling

Intercept events that disrupt the normal flow of a program's execution.

ISP

Internet Service Provider is a company that has access to the Internet backbone and provides a connection to the backbone.

NUXI ordering

Issues with byte order are sometimes called the NUXI problem: UNIX stored on a big-endian machine can show up as NUXI on a little-endian one.

Threaded Discussion group

Messages organized by topic, historical messages available, electronic form of communication

Agile Development Model

Most agile development methods break product development work into small increments that minimize the amount of up-front planning and design. Iterations are short time frames (timeboxes) that typically last from one to four weeks. Each iteration involves a cross-functional team working in all functions: planning, analysis, design, coding, unit testing, and acceptance testing.

NRO

National Reconnaissance Office is a government organization that exists to build and operate satellites for the Department of Defense and CIA

JavaScript

OOL that can be used on web pages to complete calculations and process information

Online chat

Online chat may refer to any kind of communication over the Internet that offers a real-time transmission of text messages from sender to receiver. Chat messages are generally short in order to enable other participants to respond quickly. Thereby, a feeling similar to a spoken conversation is created, which distinguishes chatting from other text-based online communication forms such as Internet forums and email. Online chat may address point-to-point communications as well as multicast communications from one sender to many receivers and voice and video chat, or may be a feature of a web conferencing service

Ctrl-O

Open an existing document

Ctrl-N

Opens a new document

random access file

Random access files permit nonsequential, or random, access to a file's contents. To access a file randomly, you open the file, seek a particular location, and read from or write to that file.

Incremental Development Model

Replaced waterfall, design implemented in pieces, includes development and maintenance

Ctrl-S

Saving a document

Waterfall Development Model

Specs, analysis, design, development, test, final product. Linear and changes are significant and costly. There is no built-in process to make changes. One step completed before the next step starts.

F7

Spell Checking a document

Flowchart ovals

Start and Stop process

SRAM

Static RAM does not need to be refreshed by the CPU and is faster than DRAM

BMP

The BMP file format, also known as bitmap image file or device independent bitmap (DIB) file format or simply a bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device (such as a graphics adapter), especially on Microsoft Windows and OS/2 operating system, used in Microsoft Paint program

GIF

The Graphics Interchange Format (better known by its acronym GIF) is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability, used on web pages and online venues

double data type

The double data type is a double-precision 64-bit IEEE 754 floating point. Its range of values is beyond the scope of this discussion, but is specified in the Floating-Point Types, Formats, and Values section of the Java Language Specification. For decimal values, this data type is generally the default choice.

Flowchart

Used to present the steps needed to solve a problem.

F1

Windows and MS programs allow users to press F1 to obtain help

function

a method or module that performs a calculation and returns a value, called a return method, easily modified one time for all uses.

procedure

a module that performs a task like sorting or printing without returning a value.....void method

method

a process in Java that is either a procedure called a void method that performs and action or a function called a return method that returns a calculated value

complete tree

all nodes to the left are filled

microchips

also known as integrated circuits, they contain electric devices like transistors, capacitors, wires, resistors and logic gates

Linked list

an ordered set of data elements, each containing a link to its successor (and sometimes its predecessor), flexible and able to grow, does not need contiguous memory

BIOS

basic input output system, tells the computer how to start up, located on the ROM, also responsible for accessing the hard drive

class

blueprint of how the object will act, it describes the attributes and methods....

ethernet cable

cable with four twisted pairs, used for networking, the ethernet connects a computer to a modem, another computer, or to a hub.

static memory

cannot grow or shrink

RJ-11

connector four pairs of wires for telephone cords

RJ-45

connector on all 8 wire systems

Flowchart diamonds

decision

kernal

deep down work running the system, hidden and protected from the user, core of the operating system that controls files, devices, and managing memory, lives in RAM

worm

designed to spread from one computer to another, sometimes carrying a virus, sometimes spreading without doing any damage...A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers.[1] Often, it uses a computer network to spread itself, relying on security failures on the target computer to access it. Unlike a computer virus, it does not need to attach itself to an existing program.[2] Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

merge sort

divide in half, then continue to divide and then merge back in sorted order, most efficient, uses twice as much memory as required for array, always O(NlogN) sort (list, lo, midpoint) sort (list, middpoint, high)

quick sort

efficient, uses divide and conquer, left side of pivot and right side of pivot...compares, swap if needed, and then both move in towards pivot Best Case O(NlogN) already sorted Average Case O(NlogN) fairly balanced Worst Case O(N*N) list is off balanced

virtual memory

excess memory on the hard drive when the RAM is full, used to hold files and program parts.

Reading data from a file

first step is to make sure file exists!

document

flowchart rectangle with wavy bottom

binary tree

heap and binary search tree, dynamic memory, linked, not in contiguous memory, parent went left and right children

motherboard

hub of the computer network, enables the electric power that enters the computer to be evenly distributed

Flowchart parallelogram

input data or output data

assembly language

low level language with three letter mnemonics

tree transversals

preorder - output left side, inorder - touch middle, post-order - output right side

Flowchart rectangles

process step

RAM

random access memory, A random-access memory device 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, contains the kernal

bits

sound waves changed to digital bits, images are digitized to pixels which are stored as a binary number

integer data type

stores integer values positive and negative

TIFF

tagged image file format, creates high resolution printable images, TIFF is a computer file format for storing raster graphics images, popular among graphic artists, the publishing industry,[1] and photographers. The TIFF format is widely supported by image-manipulation applications, by publishing and page layout applications, and by scanning, faxing, word processing, optical character recognition and other applications

formal parameters

temporary variable listed in the header and used during the call but only exists when the method or function is running

piracy

the act of stealing or replicating software without authorized permission

parameters passed by reference

the memory location of the actual parameter is passed to the formal parameter. Changes to the formal parameter inside the method or function, immediately change the actual parameter.

Dual Core Processor

two microprocessors on a single chip

actual parameters

value expression or variable, used in the method call