OS X Definition OS X is Apple's operating system that runs on Macintosh computers. It was first released in 2001 and over the next few years replaced Mac OS 9 (also known as Mac OS Classic) as the standard OS for Macs. It was called "Mac OS X" until version OS X 10.8, when Apple dropped "Mac" from the name. OS X was originally built from NeXTSTEP, an operating system designed by NeXT, which Apple acquired when Steve Jobs returned to Apple in 1997. Like NeXTSTEP, OS X is based on Unix and use...

Register Definition A register is a temporary storage area built into a CPU. Some registers are used internally and cannot be accessed outside the processor, while others are user-accessible. Most modern CPU architectures include both types of registers. Internal registers include the instruction register (IR), memory buffer register (MBR), memory data register (MDR), and memory address register (MAR). The instruction register fetches instructions from the program counter (PC) and holds each in...

Process Definition A process is a program that is running on your computer. This can be anything from a small background task, such as a spell-checker or system events handler to a full-blown application like Internet Explorer or Microsoft Word. All processes are composed of one or more threads. Since most operating systems have many background tasks running, your computer is likely to have many more processes running than actual programs. For example, you may only have three programs running, ...

Kernel Definition A kernel is the foundational layer of an operating system (OS). It functions at a basic level, communicating with hardware and managing resources, such as RAM and the CPU. Since a kernel handles many fundamental processes, it must be loaded at the beginning of the boot sequence when a computer starts up. The kernel performs a system check and recognizes components, such as the processor, GPU, and memory. It also checks for any connected peripherals. As the OS loads and the gra...

DirectX Definition DirectX is a set of standard commands and functions that software developers can use when creating their programs. While any Windows-based software program can include DirectX commands, they are usually used in video games. For example, developers may use DirectX for controlling video playback, sound effects, and peripheral input (such as a keyboard, mouse, or joystick). By incorporating DirectX functions into a computer game, programmers can use predefined commands to manage ...

OpenGL Definition OpenGL, short for "Open Graphics Library," is an application programming interface (API) designed for rendering 2D and 3D graphics. It provides a common set of commands that can be used to manage graphics in different applications and on multiple platforms. By using OpenGL, a developer can use the same code to render graphics on a Mac, PC, or mobile device. Nearly all modern operating systems and hardware devices support OpenGL, making it an easy choice for graphics developmen...

Emoji Definition An emoji is a small icon that can be placed inline with text. The name "emoji" comes from the Japanese phrase "e" (絵) and "moji" (文字), which translates to "picture character." Since 2010, the popularity or emojis have grown rapidly. They are commonly used in text messaging, social media, and in apps like Instagram and Snapchat. They have largely replaced emoticons as the standard way to express an emotion in a message or comment. While smiley faces are the most commonly used e...

Plug-in Definition Though software plug-ins might not make your room smell as nice as the scented ones you stick in an outlet, they are still useful. A software plug-in is an add-on for a program that adds functionality to it. For example, a Photoshop plug-in (such as Eye Candy) may add extra filters that you can use to manipulate images. A browser plug-in (such as Macromedia Flash or Apple QuickTime) allows you to play certain multimedia files within your Web browser. VST plug-ins add effects f...

Software Definition Computer software is a general term that describes computer programs. Related terms such as software programs, applications, scripts, and instruction sets all fall under the category of computer software. Therefore, installing new programs or applications on your computer is synonymous with installing new software on your computer. Software can be difficult to describe because it is "virtual," or not physical like computer hardware. Instead, software consists of lines of ...

RTE Definition Stands for "Runtime Environment." As soon as a software program is executed, it is in a runtime state. In this state, the program can send instructions to the computer's processor and access the computer's memory (RAM) and other system resources. When software developers write programs, they need to test them in the runtime environment. Therefore, software development programs often include an RTE component that allows the programmer to test the program while it is running. This ...