Chapter 1-2 Flashcards
Define hardware
physical devices that you see on your desktop
define software
programs that give the hardware useful functionality
name the two types of software
system software and application software
What is a user interface, and what’s an example of one
it supports moment to moment communication between the user and the computer: like a keyboard and mouse
what is an example of an auxiliary input output device
printers and scanners
what are auxiliary storage devices, and what’s an example of one
it’s basically secondary memory. examples would be hard disks, CD ROMS, and flash memory sticks
network connection
so, connection to the internet, with routers and modems
what is internal memory?
it is RAM (which is random access memory or primary memory). it’s fast and relatively small
what is a central processing unit?
it performs the work on a computer, consists of billions of transistors
what is a bit?
smallest unit of information. processed by a computer
what is a byte?
8 adjacent bits
what is a byte’s location in memory called?
its’ address
how would you look at the software development process
through the waterfall method
name the steps of the waterfall method
- customer request 2. analysis 3. design 4. implementation 5. integration 6. maintenance
what’s mnemonic device you can use for the waterfall method
CADIIM
which phase is the most expensive in the waterfall method
maintenance
what is encapsulation
combining the description of resources and behaviors in a single software entity
what is inheritance
the hierarchical class structure and sharing of instance variables and methods with subclasses
what is polymorphism
different types of objects can understand the same message.
true or false: an object’s response to a message does NOT depend on the object’s class
false. an object’s response to a message DOES depend on the object’s class
what is information hiding
it’s providing access to services, but not to data resources.
true or false: classes are organized in a hierarchy
true. classes are organized in a hierarchy
what does a root class do
it defines methods and instance variables shared by its subclasses.
what do subclasses do
they define additional methods and instance variables
what type of language is java?
it is a modern object oriented language.
why is java secure? (think about construction)
it is secure because it enables construction of virus free, tamper free systems
why is java robust? (think about development)
it is robust because it supports development of programs that do not overwrite memory
why is java portable? (think about how it runs)
it is portable because it can be run on different types of computers without change
true or false: java supports threads
true! java does supports threads!! it’s a process that can run concurrently with other processes
Java resembles ___.
java resembles C++. it’s easy for C++ programmers to learn Java
what are the weaknesses of Java?
it’s slow and it’s prone to viruses because it’s commonly used
what is a java virtual machine?
the java compiler translates Java source code into java byte code
what is byte code
it’s pseudo machine language, executed by the JVM
what is an interpreter
a program that behaves like a computer
why is a virtual machine great?
basically: all machines use a different machine language - before you’d have to write a program that could only run on one type of machine.. if you wanted to run it somewhere else, you’d have to rewrite the program. now, you can write once, run everywhere
what are java applets?
java programs that run in a Web browser. a JVM is incorporated into the browser
two types of user interface style:
graphical user interface (program interacts with users via windows with graphical components) and terminal input output interface (programs interact with users via a command terminal)
what is a program
it’s a sequence of instructions that perform a task
what is source code
the programming language instructions for a program
what is the file extension type for a java source code file?
.java
what is the file extension type for a java class file?
.class
what are the steps to make a java program?
- edit the .java file 2. compiling turns .java file into .class file 3. execute the program
what does the import statement do
allows us to use classes that other programmers have written. it also tells the java compiler where to find specifications for the class
what should we use when writing source code?
use a text editor, integrated development environment (we use BlueJ which detects syntax errors)
the main factor affecting readability is ______.
layout
true or false, the compiler does not ignore layout
false. the compiler DOES ignore layout
why is it important for you code to be readable by others?
because it may be maintained by others
