Computer Science: Section 4

Front 1

System Software

Back 1

Software needed to run the computers hardware and application programs.

Front 2

Operating system

Back 2

Resource management - managing all the computer hardware

Provision of user interface (windows) to enable users to perform tasks such as running programs.

Front 3

Utility Programs

Back 3

System software designed to optimise the performance of the computer or tasks such as backing up files, restoring corruption, etc.

Front 4

Libraries

Back 4

Ready-compiled programs which can be run when needed.

Front 5

Application Software

Back 5

Specific user-oriented task:

General-purpose software - word processor, spreadsheet, etc.

Special-purpose software - performs a single specific task or set of tasks.

Front 6

Machine code

Back 6

First bits - holds an opcode

Last bits - holds an operand

Front 7

First high-level language

Back 7

FORTRAN

Front 8

Advantages of high-level languages

Back 8

- easy to learn

- easier and faster to write

- easier to understand

- built in library functions

Front 9

Assembler

Back 9

Converts assembly language (source code) into machine code (object code)

Front 10

Compiler

Back 10

Translates high-level code into machine code.

Front 11

Interpreter

Back 11

Looks at high-level code line by line and, if there are no syntax errors, calls a subroutine to execute the command.

Front 12

Bytecode

Back 12

A result of high-level languages being compiled and interpreted at once (intermediate) which is executed by a bytecode interpreter.

Front 13

Advantages of bytecode

Back 13

Platform independence - the java virtual machine in a computer understands bytecode and converts it to machine code.

Acts as extra security between a computer and a program.

Front 14

Compilers vs interpreters

Back 14

C - there’s no need to recompile after closing a program unless an error is found.

C - object code executes faster.

C - object code is more secure.

I - useful for program development as there is no lengthy recompilation when errors are found.

I - easier to debug programs.

Front 15

NOT gate

Back 15

-|>o-

1-0

0-1

Ā (not A)

Front 16

AND gate

Back 16

=D-

0 0 , 0 1 , 1 0 = 0

1 1 = 1

A • B

Front 17

OR gate

Back 17

Back (Definition)

Front 18

XOR gate

Back 18

Back (Definition)

Front 19

NAND gate

Back 19

=Do-

0 0 , 0 1 , 1 0 = 1

1 1 = 0

Front 20

NOR gate

Back 20

Back (Definition)