Icon bar

In computing, the icon bar is the name of the dock in Acorn's RISC OS operating system, and is fundamental to the OS. Its introduction in 1987 (as part of "Arthur", the predecessor to ) was a new concept in GUIs. It displays icons through which access is provided to all parts of the computer that a typical user will require, from physical devices and system utilities to running applications, and will usually be their starting point for interacting with the system once it has finished booting.
Appearance and features.
The bar is fixed in height and located at the bottom of the screen. It takes up the full width of the screen, and a single row of icons is displayed within. Icons are either justified to the left or the right edge of the screen, at the control of the owning program. According to Acorn's official RISC OS Style Guide, a program should place its icons to the left hand side of the icon bar if they relate to physical devices or resources such as filing systems. These will have an item of text underneath them identifying the device or resource. All other icons should be placed on the right of the bar. If too many icons are present to be displayed at once then the icon bar will extend horizontally and become wider than the screen; in order to access the non-visible icons the user must scroll the bar by hovering the mouse pointer at the appropriate edge of the screen.
The result of clicking the left mouse button (known as the "Select" button) on an icon will vary depending on what the icon represents. For filing systems, a filer window will open containing the contents of the root directory. For document-oriented applications supporting multiple open documents, clicking "Select" will open a window containing a new, empty document. This is different from the behaviour of the typical Taskbar and Dock, where clicking an icon will result in a task switch (All windows associated with the icon will be brought to the front of the window stack and will gain input focus). For programs that do not support multiple open documents, clicking its icon will typically result in the task switch behaviour.
By pressing the middle ("Menu") mouse button while the pointer is over an icon, a context-sensitive menu associated with that icon will open. Although the owner of the icon is responsible for the contents of the menu, the menus for icons with similar functions will typically contain the same subset of options. For example, filing systems will allow the naming and formatting of disks, as well as an option to open a window displaying free space. Most applications will provide access to an "Info" window (displaying the version number and copyright information), online help, and a quit option.
Drag and Drop, Filer Icons (File or Directory) can be dragged and dropped on top of an icon bar icon to initiate a process, if the object type is known to the application. For example:
Even if there are no running applications or active filing systems, the icon bar will contain a small number of system-managed icons:
In RISC OS 3 the AddTinyDir star command was introduced, which allows an icon for any file, folder or application to be added to the left-hand side of the icon bar. This provides functionality similar to that later embodied in the Mac OS X dock.
History and evolution.
Arthur.
The icon bar first appeared in the Arthur operating system, in 1987. To the right was an "Exit" icon, which provided an exit to the command line (later to be replaced by the "Task Manager"). In keeping with the operating system as a whole, the icon bar reflected the multicolour appearance, being orange in colour
RISC OS 2.
RISC OS 2 in 1988 introduced the "Task Manager" and "Display" icons, with the "Task Manager" adopting Acorn's Archimedes logo. The colour scheme was also revised and a suite of applications supplied on floppy disk. Amongst these was one called "TinyDirs", which allowed users to dock applications and directories on the icon bar for convenient access.
RISC OS 3.
RISC OS 3 in 1991 introduced the "Apps" icon to the left and replaced the "Task Manager"s Archimedes logo with the Acorn nut. "Apps" provided access to the ROM based applications and the functionality of "TinyDirs" was replaced by the OS command "AddTinyDir". The "Shift-F12" keyboard shortcut and icon grouping were also added, with the intention of simplifying the finding of desired icons.
The whole of RISC OS, including the icon bar, was given a facelift in 1993 including replacement of the flat grey colour with a textured wallpaper. This was referred to as the 3D "Look and Feel".
In 1994, this 3D look was provided as standard with the release of RISC OS 3.5 on the series.
The "nested Wimp" introduced in 1998 (as a soft load for existing machines) added the feature to temporarily bring the icon bar to the front of the window stack by moving the pointer to the bottom of the screen (previously this required "Shift-F12" on the keyboard).
RISC OS 4.
RISC OS 4 in 1999 introduced the facility for iconised windows to be sent to the icon bar rather than the Pinboard. The facelift introduced in RISC OS 3.5 was also incorporated directly into the OS, as well as the method of popping the icon bar to the front. The "Task Manager" icon was again replaced, this time with the cube logo used by . Later versions of replaced the "Task Manager"s cube with the cogwheel, designed by Richard Hallas.
RISC OS 5.
RISC OS 5 in 2002 introduced further changes in icon design, including the Iyonix 'blue jellybean' "Task Manager" icon, again designed by Richard Hallas.
RISC OS 6.
RISC OS 6 in 2006 introduced the number 6 in the centre of the "Task Manager"s cogwheel icon. Where appropriate, Adjust (right mouse button) clicks perform consistent operations such as loading the configuration choices for parts of the system.