Tab key (abbreviation of tabulator key) on a keyboard is used to advance the cursor to the next tab stop. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. In Computing, a keyboard is an Input device partially modelled after the typewriter keyboard which uses an arrangement of buttons or keys Alphanumeric keyboards include Typewriters and Computer keyboards. A tab stop on a Typewriter is a location where the carriage movement is halted by mechanical gears
When a typist wanted to type a table, there was a lot of time-consuming and repetitive use of the space bar and backspace key. A typewriter is a mechanical or Electromechanical device with a set of "keys" that when pressed cause characters to be printed on a medium The space bar, spacebar, or space key, is a key on an Alphanumeric keyboard in the form of a horizontal bar in the lowermost row significantly wider To simplify this, a bar was placed in the mechanism with a moveable lever for every position across the page. Initially these were set by hand but later a tab set and tab clear keys were added. When the tab key was depressed the carriage advanced to the next tab stop. These were set to correspond to the particular column locations of the table, hence tab, being worked on. The tab mechanism also came into its own as a rapid and consistent way of uniformly indenting the first line of each paragraph. English An indentation can mean two things To make notches in something or form deep recesses in a coastline for instance
Several tab characters are included as ASCII control characters, used for text alignment. American Standard Code for Information Interchange ( ASCII) The most known and common tab is a horizontal tab, which in ASCII has the decimal character code of 9. A vertical tab also exists and has ASCII decimal character code 11. The EBCDIC code for HT is 5. Extended Binary Coded Decimal Interchange Code ( EBCDIC) is an 8- Bit Character encoding ( Code page) used on IBM mainframe Operating The VT is 11 or hex 0B, the same as ASCII. The horizontal tab is usually generated by the tab key on a standard keyboard.
Originally printers used mechanical tab stops to indicate where the tabs went. This was done horizontally with movable metal prongs in a row and vertically with a loop of mylar or other tape the length of a page with holes punched in it to indicate the tab stops. Initially these were manually set to match the preprinted forms the printer was going to print. The intention was to have the machine be programmed with other control characters to set and clear the stops but it is unclear if any popular printers implemented this. Instead it was rather quickly replaced with fixed tab stops, at every multiple of 8 characters horizontally and every 6 lines vertically, so they simply became a form of data compression, since a printing program could easily add the necessary spaces to move to any position wanted on a form. The vertical size was chosen to be 1 inch. It is unclear why the 8-character horizontal size was chosen, as 5 characters, half inch in a typical printer at that time, was much more popular at that time as a paragraph indentation. It may have been chosen to match early Fortran conventions for where the statement text started after the line number and continuation character. Fortran (previously FORTRAN) is a general-purpose, procedural, imperative Programming language that is especially suited to Or it may have been chosen as the smallest size that would fit numbers typically printed in a table.
ISO 8859 also includes the codes 136 Horizontal Tabulation Set, 137 Horizontal Tabulation with Justification and 138 Vertical Tabulation Set. ISO/IEC 8859 is a joint ISO and IEC standard for 8-bit Character encodings for use by computers
Tabs are almost always rendered as a form of whitespace larger than a single space, while some text editors mark tabs with special graphics to facilitate distinguishing tabs and whitespaces. In Process management, the White Space as described by Geary A In word processor applications, the tab key typically moves the cursor to the next tab stop. A tab stop on a Typewriter is a location where the carriage movement is halted by mechanical gears In most other graphical applications, the tab key will shift the focus to the next control or widget. In computer programming a widget (or control) is an element of a Graphical user interface (GUI that displays an information arrangement changeable by the user
A UNIX program,
expand expands a tab to a number of spaces and
unexpand does the opposite. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer
Text divided into fields delimited by tabs can be pasted into a word processor and formatted into a table with a single command.
HTML represents the horizontal tab as but as with all whitespace characters this does not allow actual insertion of tabs into the page except inside <pre></pre> tags. HTML, an initialism of HyperText Markup Language, is the predominant Markup language for Web pages It provides a means to describe the structure
Here is an example showing the use of with <pre></pre> tags. If you write in HTML:
<pre>These 2 lines are tabbed:2005 	 This line uses a tab space. 	 This line also uses a tab space. This line does not use a tab space. </pre>
The result would be something like this:
These 2 lines are tabbed:2005 This line uses a tab space. This line also uses a tab space. This line does not use a Tab space.
The vertical tab is � but is not allowed in SGML, including HTML and XML 1. The Standard Generalized Markup Language ( ISO 88791986 SGML) is an ISO Standard Metalanguage in which one can define Markup languages Don't change "Extensible" 0.
. In Process management, the White Space as described by Geary A . . 2. All tabs (U+0009) are rendered as a horizontal shift that lines up the start edge of the next glyph with the next tab stop. Tab stops occur at points that are mutiples of 8 times the width of a space (U+0020) rendered in the block's font from the block's starting content edge.
In computer programming, the use of tabs for code formatting and indentation is an ongoing debate. English An indentation can mean two things To make notches in something or form deep recesses in a coastline for instance The vast majority of code is written as plain ASCII, lacking the extra formatting information more elaborate markups and proprietary file formats provide. Some programmers consider the use of 8 spaces per tab to be excessive, such as when viewing very deeply nested and therefore very deeply indented, lines of code. Programmers who favor wide tabs often point out that deeply indented code is a bad thing in itself. 
Programmer's editors usually default to having the tab key generate hard tabs, that is actual HT characters but some editors expand them to space (SP) characters instead, often referred to as soft tabs. Most programmer's editors can be configured to perform either.
There are many arguments for and against using hard tabs in code. The most incompatibility and conversion issues ensue when the tab key generates HT characters and the editor is configured for tab stops spaced anything but the de facto standard, which for Unix, Unix-derived systems and older systems is every 8 characters and for Windows programming, every 4 characters. Interesting possibilities include 2 and even 3. When deviating from the system's de facto standard, then inevitably some lines will be formatted with spaces, others with tabs or even both. As soon as the code ends up on someone else's screen it will look different and usually jumbled and untidy if their editor's tabstop width is set differently.
One early benefit of tabs, ie: compression is now considered less relevant as desktop storage has become cheaper and sophisticated compression algorithms can provide much greater benefits, albeit at the cost of greater complexity.
Linus Torvalds has remarked that "Tabs are 8 characters, and thus indentations are also 8 characters. Linus Benedict Torvalds ( ˈtuːrvalds born December 28 1969 in Helsinki, Finland) is a Finnish software engineer There are heretic movements that try to make indentations 4 (or even 2!) characters deep, and that is akin to trying to define the value of PI to be 3. "