DESKTOP.INF File Format

Ben A L Jemmett (ben.jemmett@ukonline.co.uk) - October 10th, 1999.

About this document

This document is an attempt to describe the format of the DESKTOP.INF file, which is used by the GEM Desktop to store information about the GEM environment and user settings, Desktop window size and position, application settings and any other options that are kept for future use.  I will try and include as many settings as possible from the original Desktop 3 source and from my newer Desktop sources.   Options not present in the original Desktop are noted as such.

General structure

The DESKTOP.INF file is made up of many lines of information, each beginning with the '#' symbol, and each line describing one part of the Desktop environment.  The second character on each line indicates which setting the line describes.  The rest of the line is ASCII text, containing information specific to the individual setting.

The file can be opened and edited by any editor capable of reading and writing plain ASCII text - if you want to modify the file by hand make sure you turn off any formatting your editor might support (WordStar, for instance, might set the high bit of some characters, which will confuse the Desktop).

GEM and Desktop environment settings

The first line of the DESKTOP.INF file is usually the environment and preferences setting.  This begins with '#E' and is followed by either four or six hexadecimal digits.  These encode the settings in the 'Set preferences...' dialog box, along with the Arrange menu selections.  Each pair of digits represents one byte, with the two or three bytes being set out as follows:

First byte:

Second byte:

Third byte:

(only present in the FreeGEM Desktop 3.15 - using this on previous versions may cause unpredictable results)

System colour setting

The second line of a DESKTOP.INF created with the FreeGEM Desktop 3.15 should contain the user's colour settings.  These are represented by the code '#C' and 28 digits representing the colour scheme.  The digits are grouped into 7 groups of 4, with the digits within each group representing four nibbles:

Each group of four nibbles represents one item in the Set Colours dialog box, as follows:

Window definitions:

Window definitions take the form '#W' followed by 7 pairs of digits, a space, a path specification and a commercial at (@) sign.  The path specification may include a file specification if you wish.  It may also be blank, in which case the Desktop displays the Disk Drives: view.  In the FreeGEM 3.15 Desktop from build 19991005 onwards, an exclamation mark (!) may be used to display the Installed Applications window.   The seven pairs of digits represent bytes, and are ordered as follows:

Accessories to load

In GEM/XM (and maybe other multi-application versions of GEM), a list of installed desk accessories and their required memory size is stored next, in the form '#A', two digits representing the size, a space, and the accessory's filename.

Desktop icons

Icons that are displayed in the Disk Drives: window (or on the desktop in GEM/1 and future versions of Desktop) are represented in the form #Lxxyyiitt M label @ specification@, where L is a letter specifing the object type, xx and yy are hexadecimal bytes representing the x and y co-ordinates of the icon on the desktop, ii is a hexadecimal byte representing the icon number for the icon, tt is unused but could be used in future versions, M is the drive letter displayed in the icon, label is the string displayed underneath the icon and specification is the path and file specification for shortcuts only.   L (object type) currently takes the following values:

Applications (ANODES)

An ANODE is a structure used by the Desktop to represent an application and it's data files, folders and general files on the disk.  They take the form #Liitt application @ documents@, where L is a letter specifing the object type, ii and tt are hexadecimal bytes representing the icon numbers for the application icon and document icon respectively, application is the application's file name icon and documents is a list of document filetypes associated with the application..  L (object type) currently takes the following values:

Some values are standard to allow the Desktop to display icons for generic files and folders.  These are #FFF28 @ *.*@, #DFF02 @ *.*@, #G08FF *.APP@ @, #P08FF *.EXE@ @, #P08FF *.COM@ @, and #P08FF *.BAT@ @.  These must be present in Desktop builds from 19990830 onwards, otherwise unregistered applications will not display properly.