COMP 2401 - Chapter 1

Systems Programming

The programming of software that provides services for other software or for the underlying computer system.

Operating System

System software that manages computer hardware and software resources and provides common services for computer programs.

Applications Programming

The programming of software to provide services for the user directly.

Systems Software

The layer between the hardware and application software that deals directly with the hardware and usually controls it.

Efficiency

Making efficient use of resources such as computer memory, disk space, and CPU time.

System Calls

Requests made by applications to the operating system for access to resources.

File I/O

Functionality provided by the operating system for file system organization, access to read and write files, and setting access permissions.

Device I/O

Functionality provided by the operating system for communication with devices through their drivers and managing shared access.

Process Management

Functionality provided by the operating system for starting, stopping, and altering running executables, as well as allocating memory for each process.

Virtual Memory

Functionality provided by the operating system to provide memory to every process, appearing as a large amount of contiguous memory but may be fragmented in main memory or on disk.

Scheduling

Functionality provided by the operating system to allow applications to share CPU time and device access.

Shells

Command line user interfaces that allow access to an operating system's services and the ability to run other programs.

Shell Commands

Common commands that can be used within a shell, such as alias, cd, pwd, set, and which.

System Programs

Common programs that can be used within a shell, such as grep, ls, more, time, and sort.

Man Pages

User manuals accessed through the man command in a shell, providing help and documentation for various commands and programs.

Text Editor

A program that allows you to produce a text-based file.

Compiler

Computer software that transforms source code written in one programming language into another target programming language.

Debugger

A program used to test and debug other programs.

Object Code

The output of the compiler, which is meant to be run on a specific machine.

Executable File

A runnable program produced by linking object files with various library files.

"Hello World" Program

A simple program that outputs the words "Hello World" to the computer screen.

Header File

A file containing C declarations and macro definitions to be shared between several source files.

A function used in C to print text to the screen.

printf()

The entry point of a C program, where the program execution begins.

main() function

Braces and Semi-colons

Syntax elements used in C to define blocks of code and terminate statements.

Object file

A file generated by the compiler that contains the compiled code of a single source file.

ls command

A command used in the command line interface to list the files and directories in a directory.

gcc

The GNU Compiler Collection, a compiler system used to compile C and C++ programs.

Linking

The process of combining object files and library files to create an executable file.

Executable file

A file that can be run or executed by the computer.

The command used to run the executable file in the current directory.

.filename

A function in C used to print formatted output to the console.

printf

A format specifier used in printf to print integers.

%d

A format specifier used in printf to print floating-point numbers.

%f

A format specifier used in printf to print floating-point numbers with exponential precision.

%g

A format specifier used in printf to print characters.

%c

A format specifier used in printf to print strings.

%s

A format specifier used in printf to print integers in hexadecimal format.

%x

A format specifier used in printf to print integers in octal format.

%o

A parameter in printf that specifies the minimum number of spaces the output will take up.

Width parameter

A parameter in printf that specifies the number of digits or characters to be displayed.

Precision parameter

%6.1X

A format specifier used in printf to print an unsigned hexadecimal integer with a minimum width of 6 characters and 1 digit after the decimal point.

%6.3d

A format specifier used in printf to print a decimal integer with a minimum width of 6 characters and 3 digits after the decimal point.

flags parameter

A parameter in printf that allows us to indicate how many leading zeros will be displayed when used with integer, unsigned integer, octal, and hexadecimal flags.

0 flag

A flag in printf that allows leading zeros to be inserted when used with numbers.

A flag in printf that allows a plus sign to be inserted for positive numbers.

+ flag

A flag in printf that allows everything to be left-aligned when used with numbers or strings.

- flag

A conditional statement in C that allows for the execution of a block of code if a certain condition is true.

IF statement

A conditional statement in C that allows for the execution of different blocks of code based on the value of a variable.

SWITCH statement

A data type that can have one of two values, typically true or false, used for logical operations.

Boolean

A keyword in C used to define fixed values or constants.

#define

ASCII code

A character encoding standard that represents text in computers and other devices.

UNICODE character set

A character encoding standard that aims to include all characters from all writing systems in the world.

Fixed values/numbers

Values or numbers that are defined using the #define keyword in C and are typically used as constants in the program.

Ternary/conditional operator

An operator in C that allows for a shorter form of an if-else statement and can also provide a returned value for use in a calculation.

A loop in C that allows for the execution of a block of code for a specified number of times.

FOR loop

A loop in C that allows for the execution of a block of code as long as a certain condition is true.

WHILE loop

DO/WHILE loop

A loop in which the condition is checked at the end of the loop, guaranteeing that the loop is evaluated at least once.

break statement

A statement used to exit a loop prematurely, skipping the remaining iterations.

continue statement

A statement used to skip the current iteration of a loop and move on to the next iteration.

efficiency

The measure of how quickly and effectively a program runs.

running time

The amount of time it takes for a program to execute.

An operator used to increase the value of a variable by 1.

increment operator (++)

An operator used to decrease the value of a variable by 1.

decrement operator (--)

An operator used to assign a value to a variable.

assignment operator (=)

Operators used to compare values and determine the relationship between them (e.g.,

relational operators

Operators used to combine or manipulate boolean values (e.g., &&, ||, !).

logical operators

Operators used to perform operations on individual bits of binary numbers (e.g., &, |, ^, ~, <

bitwise operators

A ternary operator used to evaluate a condition and return one of two values based on the result.

conditional operator (?:)

The order in which operators are evaluated in an expression.

precedence

Operators used to perform mathematical calculations (e.g., +, -, *, /, %).

arithmetic operators

assignment operators

Operators used to assign a value to a variable and perform an operation at the same time (e.g., +=, -=, *=, /=).

An operator used to determine the size of a data type or variable in bytes.

sizeof operator

An operator used to separate multiple expressions in a statement, evaluating them from left to right.

comma operator (,)

The use of trigonometric functions in the JAVA programming language.

Trig

A mathematical function that returns the smallest integer greater than or equal to a.

ceil(a)

A mathematical function that returns the largest integer less than or equal to a.

floor(a)

A mathematical function that returns the closest integer to a.

round(a)

A mathematical function that returns a raised to the power of b.

pow(a, b)

A mathematical function that returns the square root of a.

sqrt(a)

A mathematical function that returns the absolute value of a.

fabs(a)

A function that generates a pseudo-random integer between 0 and RAND_MAX.

rand()

A function that returns the smaller of two numbers, a and b.

Math.min(a, b)

A function that returns the larger of two numbers, a and b.

Math.max(a, b)

A function in the Math class of JAVA that returns the smallest integer greater than or equal to a.

Math.ceil(a)

A function in the Math class of JAVA that returns the largest integer less than or equal to a.

Math.floor(a)

A function in the Math class of JAVA that returns the closest integer to a.

Math.round(a)

A function in the Math class of JAVA that returns a raised to the power of b.

Math.pow(a, b)

A function in the Math class of JAVA that returns the square root of a.

Math.sqrt(a)

A function in the Math class of JAVA that returns the absolute value of a.

Math.abs(a)

A function in the Math class of JAVA that generates a random double value between 0.0 and 1.0.

Math.random()

A trigonometric function that returns the sine of an angle r.

sin(r)

A trigonometric function that returns the arcsine of a value r.

asin(r)

A trigonometric function that returns the cosine of an angle r.

cos(r)

A trigonometric function that returns the arccosine of a value r.

acos(r)

A trigonometric function that returns the tangent of an angle r.

tan(r)

A trigonometric function that returns the arctangent of a value r.

atan(r)

A trigonometric function that returns the arctangent of the quotient of two values r.

atan2(r)

A sequence of numbers that appear to be random but can be set to a fixed sequence.

Random numbers

A collection of elements of the same data type that can be accessed using an index.

Arrays