Java Flashcards

Computer Science 1004 with Adam Cannon at Columbia University

About this deck

By: Ethan Kochav
Created: 2011-05-08
Size: 97 flashcards
Views: 289

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accessor method

Method that accesses an object but does not change it

ACK

Acknowledgement message; is sent back to the node that has previously sent a packet when the receiving node has received the message from the sending node.

actual parameter

The expression supplied for a formal parameter of a method by the caller

address

Unique numerical identifier

algorithm

An unambiguous, excutalbe, termating specification of a way to solve a problem

API

A code library for building programs

Argument

An actual parameter in a method call, or one of the values combined by an operator

arithmetic/Logic Unit (ALU)

The subsystem that performs such mathematical and logical operatiosn as addition, subtraction, and comparison for equality

ARQ Algorithm

Automatic, repeat, request algorithm-Used in the data link layer, it’s the protocol for one node sending a message to another-essentialy it sends a message until it receives an ACK

ASCII

American standard code for information interchange-An ineternational standard for representing textual information in th majority of computers. It uses 8 bits to represent each character, so it can encode 2^8=256 characters-

assembly language

A language designed for poepl as well as computers-was designed for the first generation of computers-low-level programming language

binary

Base 2 numbering system-used in computers

bit

One unit of information-can be 1 or 0

Boolean

A type with two possible values; true or false

boolean expression

Any expression that results in a true or false value

boolean operator

An operator that can be applied to Boolean values. Java has three logical operators: &&, ||, and !

byte

8 bits; traditionally the accepted size for a memory cell

bytecode

Java virtual machine reads; machine language

cache memory

A type of high speed (but expensive) memory tht is 5 to 10 times faster than RAM; there is only a few mb of it, only recently accessed items are there

cast

Excplicity convering a value from one type to a different type.

Church-Turing Thesis

If there exists an algorithm to do a symbol manipulation task, then there exists A turing machine to do that task

Class

A programmer-defined data type

Compiler

A program that translates code in a high level language (Such as, for example, java) to machine instructions (such as bytecode for the java vehtual machine)

Computability

-That which can be done by symbol manipulation algoirthms

computer network

A set of independent computer systems connected by telecommunication link for the purpose of sharing information and resources.

computer science

The study of algorithms including their

· Formal and mathematical applications

· Their linguistic realizations

· Their harwardware realizations

· Their applications

computing agent

Anything that carries out the steps of an algoirthm

constructor

A method that initializes a newly instantiated object

control unit

1. Fetches from memory the next instruction to be executed

2. Decodes it-that is, determines what is to be done

3. Executes it by issuing the appropriate command to the ALU, memory, or IO controllers

DASD

direct access storage device-mass storage, different waiting times for different memories

DNS

Domain name system-a massive database that contains the host-name-to-IP-Adress

Ethernet

The most widely used broadband technology, works on the physical layer of networking

encapsulation

The hiding of impelmeentation details

explicit parameter

A parameter of a method other than the object on which the method is invoked

flops

Floating point operations per second-measures computer speed

formal parameter

A variable in a method definition; it is initialized with an actual parameter value when the method is called

gigabyte

1,000,000,000 bytes

Halting Problem

Decide, given any collection of Turing Machine instructions together with any intital tape contents, whether that Turing machine will ever halt if started on that tape

HTTP

Hypertext transfer protocol

I/O buffer

A small amount of memory that belongs to the I/O controller

I/O controller

A special purpose computer whose responsibility is to handle the details of I/O and to cmpesentate for any speed differences between the IO devices and the other parts of the comptuer

IDE

Integrated development environment; A programming environment that includes and editor, compiler, and debugger

implicit parameter

The object on which a method is onvked. For example, in the call x.f(y), the ob ject x is the implicit parameter of the method f.

interface (in Java)

A type with no instance variables, only abstract methods and constants

inheritance (in Java)

The is-a relationship between a more general superclass and a more specialized subclass

initialize

Setting a variable to a well-defined value when it is created

instance

A particular example of a data type

instance variable

A variable defined in a class for which every object of the class has its own value

instantiation

Construction

Internet Protocol

The network layer in the internet (two nodes aren’t directly connected)

instruction register

Holds a copy of the instruction fetched from memory-holds both the OP code and the addresses

instruction set

The set of all operations that can be executed by a processor

kilobyte

1,000 bytes

LAN

Connects hardware devices such as computers, printers, and storage devices that are all in close proximity

local variable

A variable whose scope is a block

logic gate

An electronic device that operates on a collection of binary inputs to produce a binary output

loop

A sequenc e of instructions that is executed repeatedly

MAC

Medium access control-protocol for determing who goes when

mass storage

Nonvalitle storage, included in I/O portion of von-Neumann computer

megabyte

1,000,000 bytes

memory

The functional unit of a computer that stores and retrives the instructions and the data being executed

Memory Address Register (MAR)

Holds the address of a RAM cell to be fetched or stored

Memory Data Register (MDR)

Contains the data vlue being fetched or stored

Method

A sequence of statements that has a name, may have formal parameters, and may return a value. A method can be invoked any number of times, with different values for its parameters.

mutator method

A method that changes the state of an object

object

A value of a class type

object reference

A value that denotes the location of an object inemeory. In Java, a variable whose type is a class contains a reference to an object of that class

object-oriented programming

Programming by discovering objects, their properties, and their relationships

op code

Operation Code-a unique unsigned integer code assigned to each machine language operation recognized by the hardware

operating system

The program that controls the overall operation of the computer

overloading a method

Giving more than one meaning to a method name

overriding a method

Redefining a method in a subclass

parameter

an item of information that is specified to a method when the method is called. For example, in the call System.out.println(“Hello, World!”), the paremters are the implicit parameter System.out and the explicit parameter “Hello, World!”

parameter passing

Specifying expressions to be actual parameter values for a method when it is called

portability

Something can be used in different OS

primitive data type

In java, number type or boolean

protocol

A mutually a greed upon set of rules, conventions, and agreements for the efficient and orderly exchange of information.

protocol stack

The protocol hierarchy; has five layers. Also known as TCP/IP after the names of its two most important protocols

1. Physical

2. Data link

3. Network

4. Transport

5. application

pseudoocode

A high level desciprtion of the actions of a program or algorithm using a mixture of English and informall programming language syntax

Random Access Memory

A type of memory that has three characterists

· Memory is divided into fixed-size units called cells and each cell is associated with a unique indentifier called an address

· Al accesses to memory are to a specified address, and we must always fetch or store a complete cell-that is, all the bits in that cell. The cell is the minimum unit of access

· The time it takes to fetch or store the contents of a cell is the same for all the cells in memory

Register

A storage cell that holds the operands of an arithmetic operation and that, when the operation s complete, holds its result

SASD

Sequential acces storage device-mass storage

Scope

The part of a program in which a variable is defined

Software

Programs

static variable

A variable defined in a class that has only one vqealue for the whole classed, which can be accessed and changed by any method of that class

static method

A method with no implicit parameter; not invoked on an object

stored program concept

One instruction at a time is fetched from memory and passed to the control unit, where it is decoded and executed

syntax

Rules that define how to form instructions in a particular programming language

terabyte

1,000,000,000,000 bytes

time complexity

quantifies the amount of time taken by an algorithm to run as a function of the size of the input to the problem.

TCP

Transport control porotocl-The primary transport protocol-Two programs at source and destination node establish a connection, transmits thorugh many data-link layers until it reaches-very reliable, unlike IP

truth table

A structure that lists the combination of Boolean outputs based on several Boolean inputs

Turing machine

Includes a conceptual tape of with symbols that extends infinitely in both directions and a series of an instructions that can manipulate these symbols

Von Neumann architecture

· Has four major substeyms of memory/input, ALU, control unit, and I/O

· Has stored program concept

Has sequential executions of instructions

white space

any sequence of only space, tab, and newline characters

WAN

Connects devices that are not in close proximity, but rather are across town, country or ocean

About this deck

By: Ethan Kochav
Created: 2011-05-08
Size: 97 flashcards
Views: 289

About StudyBlue

“I have used this website for three exams, and I see a huge difference in my test results.”
Naj