A nav cluster or sixkey is a cluster of six keys above the arrow keys on a standard keyboard, with keys for naviation. The keys are:
The typical layout was popularised by the IBM Enhanced Keyboard, but similar nav clusters have existed on earlier keyboards.
The Delete key is used to delete the character to the right of the cursor. The cursor is stationary.
In older programs, the Insert key is modal, swapping between overwrite mode and insert mode. In modern programs, insert mode is often the default or the only mode. Even though the key is used as a modal key, it is very seldom a latching or with a lock light.
In some older programs such as in the MS DOS prompt in Microsoft Windows, Control+Insert is used to Copy and Shift+Insert is used to Paste.
Home and End
When browsing a document, Home and End moves to the top and the bottom of the document, respectively. The typical usage for Home/End keys when editing text is to move the cursor to the beginning and the end of the line, respectively.
Text programs on Macintosh tend to use the browsing usages also in text editors and word-processing programs, moving the cursor to the first character or the last character in the text document.
Page up and Page Down
Page Up and Page Down moves one page's worth of text up and down respectively. Most programs for text editing or word processing move the cursor at well. Scrolling behaviour varies especially among text-mode programs.
The de-facto standard for 75% form-factor keyboards is to have the nav keys in a single column fused together with other keys. This order is sometimes broken.
Some keyboards have a 2×3 arrangement to be able to save a column.
Amiga keyboards tended to have this two-key cluster above the cursor keys:
A form of Home, End, Page Up and Page Down usages were available on Shift+cursor. In text-editing programs the convention was to move the cursor to the window edge first, and scroll only if on the edge.
The Atari ST (and TT) line had a cluster with cursor and nav keys in one:
A Delete key was to the left of the cluster, below Backspace and to the right of Return.
In arrow cluster
Another arrangement is to have cursor keys arranged in a cross with a Home key in the centre.
On some keyboards, symbols are used together with or instead of text. The usage varies somewhat.
|Key name||Short name||Macintosh||ISO/IEC "standard"|
|Insert||Ins||Help or Fn||⎀|
|Page Up||Pg Up||⇞||⎗|
|Page Down||Pg Dn||⇟||⎘|