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Glossary of Terms


Term  (abbreviation) Definition
Airport Apple's word for IEEE 802.11b wireless Ethernet or "Wi-Fi" (2.4 GHz band) see Wi-Fi
Apple Menu the leftmost menu, represented by a small Apple logo .  Should be called the system menu.
Application a program, with which you create documents or work on them.
Application Menu the menu just after the system menu
Application, active the application that is curently listening to the keyboard and mouse
Application, running the applications that are currently "awake" (in memory); only one of them can be listening to the keyboard and mouse: the active application.
Arrow keys
Bit  (b) ba single binary digit:  on or off; zero or one.
Byte  (B) amount of information represented in 8 bits; quantity to hold one character.  A piece of simple text needs 1 byte per character (each of the spaces between words also needs a byte).

An A4 page of text has approximately 50 lines of 100 characters per line, or a total of 50x100=5'000 characters. It takes 5'000 bytes to store that page, or 5kB (5 kilobytes)

Caps Lock
Close button   used to close a window definitively.  Also indicates whether the document it displays has been changed (if it has a black dot).
Command (1) A order given to an application.  One way is to select from a menu.  Another way is to type a key while holding down the command-key.  E.g. to quit from an application you can choose "Quit" from the application menu or you can type "q" while holding down the command-key.

(2) Discontiguous extension of a selection. In a list you can select any set of items by successive clicks while holding down the command-key. (Note: this usually does NOT work in text editors! (exception: Microsoft Word allows discontiguous selections with the command-key)

Command key  () Key next to the space bar (see keyboard) also called the "Apple" key. Marked with
Contextual menu
Control key bottom-left key of the keyboard.  Holding down the control-key while (left-)clicking brings up a contextual menu. Used in some special circumstances in applications.
Creator the application used to create the document (the first time it was edited).
Cursor the pointer that moves with the mouse. Can also take other shapes:
do not confuse with the insertion point
Dialog box a window to get extra user input for an action. E.g. when saving a new document a dialog box comes up asking for the file name and location.
Document the result of your work, a file on disk or server. You use applications to create and modify documents.
Eject button looks like .  There is one on the keyboard (upper right) and it also appears next to volumes in the Finder sidebar.
Ethernet a standard (IEEE 802.3i) for high-speed data transfer for networking.  Your Mac has at least one Ethernet port.  Those of new Macs can handle gigabit speed.  Normal speed is 10Mb/s, Fast Ethernet is 100Mb/s, Gigabit Ethernet is 1'000Mb/s
File a magetic recording on disk or server, usually containing a document.
Finder the application that shows you the objects in your computer (files, folders, volumes).  It is the only application that always runs.
FireWire a standard (IEEE 1394) for high-speed data transfer. FireWire400 works at 40MB/s, FireWire800 works at 80MB/s. Your Mac has at least one FireWire port. Used for connecting external discs and video cameras.
Giga 1'000'000'000  or 1'000 mega  or 1'000'000 kilo  (see tera, giga, mega, kilo) Gigabit per second  (Gb/s) Raw data speed.  It needs approximately 10Gb/s to achieve 1GB/s (more than 8 because of error correction information).  Gigabit Ethernet is now fairly standard for networking.
GigaByte  (GB) about 1'000 MB.

A CD holds 0.7GB.  A single-sided DVD holds 4.7 GB

Since video flows at 4MB/s, an hour of DV video needs 3600x4=14.4 GB of disc space to store.

GigaHertz  (GHz) a giga cycles per second.
Icon small picture representing an item in the machine. There are three essential icon types.
Icon types
IEEE  (pronounced I-triple-E) Institute of Electrical and Electronic Engineers, this organization also produces standards for the electronics industry, such as FireWire, Ethernet and wireless Ethernet
Insertion point the place in a piece of text where the next character you type will be placed. It is usually a blinking vertical bar. It can be set by clicking the mouse at the desired point. It moves with the arrow keys.
Keyboard input device with many buttons (about 102)
Kilo 1'000  (see tera, giga, mega, kilo)
KiloByte  (kB) 1'024 bytes (1'024 = 2x2x2x2x2x2x2x2x2x2; see powers of two)

An A4 page of text has approximately 50 lines of 100 characters per line, or a total of 50x100=5'000 characters. It takes 5'000 bytes to store that page, or 5kB (5 kilobytes)

Because 1'024 is close to 1'000, one commonly uses the Greek work "kilo" for both.  Strictly speaking the letter k is used for 1'000 and the letter K for 1'024.

Left button see mouse left button
Mega 1'000'000 or 1'000 kilo  (see tera, giga, mega, kilo)
MegaByte per second  MB/s Speed of data transfer.  1MB/s = 10Mb/s

Standard Ethernet flows at 10Mb/s or 1MB/s

MegaHertz  (MHz) 1'000'000 cycles per second.
Megabit per second  (Mb/s) Raw data speed.  It needs approximately 10Mb/s to achieve 1MB/s (more than 8 times because of error correction information)
MegaByte  (MB) about 1'000'000 bytes.

A typical Agatha Christie mystery novel has about 200 pages, each with 35 lines of 10 words.  An English word is on average 6 letters long, which takes 7 bytes (including the space between it ant the next word) hence 7x10x35x200 = 490'000 bytes or about half a megabyte.

A CD holds 700MB

An MP3 song is about 4MB.

The average digital photo from a 3 megapixel camera is compressed to about 1MB.

MegaByte per second  (MB/s)

Video of TV quality flows at about 4MB per second.

Standard Ethernet is 1MB per second.

Menu bar the white strip that is always present at the top of the screen.
Minimise button  used to make a window temporarily go into the dock so the document it displays is out of view but not closed.
Mouse left button the normal click button
Mouse right button the contextual menu button
Mouse scrollwheel allows to scroll without having to go to the right-hand side of the window
Mouse pointing device. Apple's have only one button, but OS X can use three buttons and a scrollwheel.  No software installation is needed to connect a three-button USB mouse; most that you buy in any hardware shop will work.
Option An extra aspect of a function. Can be activated by the Option key. E.g.: to go from the active application A to another one B, you can click one of the windows of B. There is an option to this transition:  hiding all windows of A at the same time. To do this you therefore would hold down the option-key while clicking the window of B.
Option key key to the left of the command key at the bottom of the keyboard.
PDF Portable Document Format.  A proprietary format from Adobe.  PDF files retain their presentation:  the fonts, pagination and graphical layout.  PDF files are small and readable on most platforms (Mac, Unix/Linux, Windows).
Powers of two quantities that are 2 multiplied by itself a number of times . They are:
2=2=21; 4=2x2=22; 8=2x2x2=23; 16=2x2x2x2=24; 32=2x2x2x2x2=25; 64=2x2x2x2x2x2=26; 128=27; 256=28; 512=29; 1024=210; ...
Right button see mouse right button
Shift (1) A constraint on a function.  Holding down the shift-key you get only upper-case symbols.  When dragging a rectangle in a drawing application, holding down the shift key will usually constrain the rectangle to be a square, or constrain an oval to a circle.

(2) Contiguous extension of a selection.  Holding down the shift-key while selecting in text will select from the insertion point to the cursor position.  Holding down the shift-key in a spreadsheet will select a contiguous rectangle of cells from the active cell to the cursor position

System Preferences
System menu the first menu in the menu bar.  It has the Apple logo as head: .  It has the system functions in it:  from "About this Mac" to "Shutdown".
Tab (1) key to inserts a single tabulator-character.

(2) key to move to the next field in a dialog box and select its text. Use this to fill in forms.

Tera  (T) 1'000 giga (see tera, giga, mega, kilo)
USB Universal Serial Bus. A successor to ADB (Apple Desktop Bus). Connects simple devices that do not need high speeds. USB-1 goes at 1MB/s, USB-2 goes at 45MB/s
Wi-Fi Intel's word for IEEE 802.11b wireless Ethernet (see Airport)
Zoom button  used to adapt a window's size to the screen. Toggles between this size and its normal size.
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next planned revision: 2009-01