Types of Software

Learning Goals

Identify and describe the 4 general categories of software

What IS Software?

Software is a general term used to define a set of instructions given to a computer to perform, it is not a physical piece of a computer, but it is just as important to a computer as the hardware. There are a great many different types of software, but we will stick to four general categories:

Application Software - Group of software whose purpose is to perform user tasks.
System Software - Group of software whose purpose is to start and run a computer
Development Software - Software whose purpose is to create, compile/interpret and run new software
Malware - Any piece of malicious or dangerous software whose intention is to cause damage or change a software system, steal information, or gain access to a private system (like a government website or database)

Application Software

This type of software has a set of instructions that is designed to help users, who are people using the computer, perform a task. A user task is another way of saying a job or action that a user wants to take. These jobs can range from creating a document for an essay, to playing a video game, to listening to music, to creating a database. The one thing these pieces of software have in common is that they are very specific or specialized in what they do, and that the users should not have to know how a computer works in order to use the software.

We can break application software down into some sub-categories:

Productivity Applications
- Examples: word processor (Word, Pages), spreadsheet (Excel), database (Access, Oracle), photo editors (GIMP, Photoshop)

Entertainment Applications
- Examples: video games (StarCraft, League of Legends, Solitaire), music players (iTunes, Windows Media Player, WinAmp), video players (Windows Media Player, VLC)
Business Applications
- A business application would be something that performs a specific task for a business such as finances, accounting, customer service, or project management
Education/Reference Applications
- Examples: Interactive mathematics software (Desmos, Geometer Sketchpad), encyclopedias (Encyclopedia Britannica, Wikipedia...), educational programming languages (Swift, Scratch)

System Software

System software is responsible for communication between hardware and other pieces of software. There are a few different types of system software:

Operating Systems: A large piece of software that is responsible for managing how other programs interact with various pieces of hardware, usually through device drivers. Examples: Windows, OSX, Linux, Unix
Device Drivers: Small programs that provide an Application Program Interface (API) which determines how other programs can interact with hardware.
BIOS: Program responsible for Basic Input Output of a computer.

Device Drivers:

Device drivers come in many shapes, sizes and locations. For example, when you start up your computer, you are presented with a black screen. On that black screen you may see something like the image on the right.

This is a driver that controls how your computer operates. It is called the BIOS, which stands for Basic Input Output System. Previously, the BIOS existed inside a chip of Read Only Memory (ROM) on your motherboard. This was inconvenient especially if it was discovered that there was an error in the BIOS program. Today, flash memory is used to store the BIOS so that it can be changed or updated.

The purpose of the BIOS is to start up your hardware and test to ensure that communication with that hardware works. In addition, the BIOS provides other pieces of software with an API which defines how to interact with the hardware. For example, the BIOS will have some way of changing the colour of a pixel on the screen, perhaps through an interface that looks like this: setPixelColour(position, colour).

Operating System:

An operating system is composed of:

A kernel: The main and most important part of the operating system, the kernel is responsible for defining the API (Application Program Interface) used by application software to communicate with hardware.
A user interface (UI): This defines how users (humans) can use the operating system. As you sit and read this, using a web browser, you are interacting with your operating system through the UI. UI's can be broken down into two types:
- Command Line Interfaces (CLI), like this.
- Graphical User Interfaces (GUI, sometimes pronounced "gooey") which use more complicated hardware, such as a mouse, along with concepts such as a program window or buttons to provide a visual interface.

Development Software

Development software exists for the sole purpose of allowing people like us, programmers, to create new fantastic pieces of code, or to fix old ones. There are a few key types of development software:

Compiler - a program that is used to translate code from one language (say C, Java or Python) into a language the computer itself understands (like Assembly). The result is usually a file that can be executed or run on the target system. A compiler does not execute commands.
Interpreter - By comparison to a compiler, an interpreter does execute commands. In fact, an interpreter takes a program one line at a time and execute each line as it arrives.
Integrated Development Environment (IDE) - An interface, usually graphical, that combines an editor window used to write code, an interpreter and a compiler into one package. An IDE also allows you to "debug" or execute a program one line at a time while giving access to all of the program's memory. This is done in order to find problems within the code.

Malware

Malware is a general term for any piece of software that exists to be disruptive in some way: Malicious Software. They can be broken down into a few general categories:

Viruses: When executed, a virus creates copies of itself and attempts to infect other computers by modifying files on other computers. Viruses can affect anything from how your computer boots up to how programs work.
Trojan Horses: Any program that misrepresents itself in order to be installed by a user, while hiding its true purpose is a trojan horse.
Adware/Spyware: Small malware programs that are used to collect information about the user. That information is usually used to hijack web searches and browsers to redirect traffic to websites that are not where the user intended to go.
Worms: Similar to viruses, when executed, a worm will create copies of itself. The difference is that a worm is a standalone program and does not necessarily need to modify existing programs to work.
Backdoors: A backdoor is a way of circumventing the security of a system and allowing access to files or programs without requiring authorization of the user.

Quick Definition (copy these):

Virus: Spreads by copying itself. Can affect any type of computer functionality by changing existing programs
Trojan Horse: Program or file that says it's one thing (like a video or game) and is really something else (like a virus or spyware)
Adware/Spyware: Collects information about the user and changes web searches or traffic to other sites
Worm: Like a virus except it doesn't need to change existing programs to work.
Backdoor: Any way around a security measure without authorization.

Homework

1. Classify the following programs as either Application, System, Development software or Malware. Justify your answer. You may have to search the internet.

Microsoft Word
Command Prompt (in Windows, press start button, click run, type cmd, press enter)
WingIDE
Stuxnet
Undertale
Network Card Driver
VLC

2. There are many different types of malware. Use the search term "Famous Viruses" to find a virus and answer the following questions:

What operating system was targeted?
How did the creators get people to download/install/access their virus?
How did it propagate (spread itself)?
What did the virus do?
Were the creators ever caught and charged by authorities?

3. What is a DDOS attack? Do DDOS attacks qualify as software? Why or why not?

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