Chapter 5

Application / App

a program that a user runs to carry out a user task like listening to music or surfing the web

Operating System

a program that implements the detailed interactions with hardware (among other things), presenting an application program with a more abstract interface like "Display '6' to the screen

Portability

The same application program can run without modification on different kinds of computers

File

a collection of information stored somewhere on a drive, such as a music file, movie file, word processing file, or an application

Folder

a grouping of files or other folders, that helps a user organize items

Desktop

Mac OS X and Windows both show some file/folder/app items on the OS's main graphical view

Finder / Windows Explorer

Applications for users to manage folder/file/app items

Filename Extension

Different file types typically have a different abbreviation after the filename's period (ex: .pdf)

PDF

short for Portable Document Format, describes formatted text/graphics suitable for viewing and printing, independently of apps like a word processor, web browser, etc

Microsoft Office Document

used by the Microsoft Word (.docx), PowerPoint (.pptx), and Excel (.xlsx) apps to save each apps' files in a way suitable for later editing

Executable file

an application; executables for Windows typically end with .exe.

Media File

stores a picture (jpg/png), video (mp4, mov), audio (mp3), or other media item

Multitasking OS

upports running multiple applications seemingly simultaneously

Multi-user OS

a multitasking OS that runs multiple users' applications, keeping each user's applications and files separate, and switching among applications fast enough (typically thousands of times per second) to give the user the illusion of being the only user on the computer

Device Drivers

The OS portions that interface with hardware

Unix

OS developed in the late 1960's by AT&T Bell Laboratories, focusing on multi-user support, and written in the C high-level language rather than assembly to ease implementations on different computers

MS DOS

introduced in 1981 by Microsoft as a relatively simple OS for PCs, which were new at that time

Linux

an operating system based on Unix and developed in the early 1990's by Finnish college student Linus Torvalds

popular today due in part to being free and open source

Ubuntu Desktop / Fedora

Today, popular Linux distributions, or package have a graphical interface

Windows

a graphical OS developed by Microsoft in the mid-to-late 1980s

macOS

a graphical OS developed by Apple in the early 2000's, based on the Unix OS

iOS

a graphical OS developed by Apple in 2007 for Apple smartphones and tablets

Android

a graphical OS released by Google in 2007 for smartphones and tablets, based on the Linux

Microsoft

created in 1975 to create and sell an implementation of the BASIC high-level programming language for a particular PC of that time

MS-DOS

Gates purchased an existing OS (originally named QDOS for Quick and Dirty Operating System) from another company for $50,000, and introduced

Windows

MS-DOS use grew to millions of users within a few years, eventually leading to

Apple Computer

Jobs and Wozniak founded ——— in 1976 to build personal computers, a new and exciting kind of computer at the time.

Mac OS

Apple developed an OS for apple known as

NeXT Computer

after leaving Apple, Jobs founded

Activity Monitor / Task Manager / top

Mac OS X provides the Activity Monitor app for seeing each app’s CPU and memory usage

Process / Task

is an independently running program, perhaps a user's app, or an OS app, or part of a larger app

Memory Leak

The longer the app runs, the more memory the app uses, even though the app doesn't really need the additional memory

Backup File

a copy of a file intended as a replacement in case the original file is lost

Manual Backup

involves a user intentionally copying files to another location.

Automated Backup System

makes regular backups of a user's files, either as the files are updated, or on a schedule like daily or weekly

Trash / Recycle Bin

For the common case of a user accidentally deleting a needed file, many operating systems don't really delete the file from the drive, but rather move the file to ___

Device Drivers

The OS portions that interface with hardware are often called