GAP Installation on Windows

To install GAP on a Windows system follow these steps. It is assumed that you have downloaded the gap4r4p12... and packages-... archives and know how to unpack them. (Otherwise go back to the download description.)

• Unpack the gap4r4p12... archive on the top-level directory of drive C:\. This creates a directory C:\gap4r4.

  Optional: If you have downloaded one or some of the optional archives xtom..., htmie4r4..., and tools4r4..., unpack them in the same place where you have unpacked the gap4r4... archive.

• Unpack the GAP packages provided by the packages-... archive inside (!) the directory C:\GAP4r4\pkg\. Note that some packages will not provide their full functionality under Windows because they need some external background programs, which are not available.

• Now GAP can be started by clicking on C:\gap4r4\bin\gap.bat. You may want to create an entry in a start submenu of your choice pointing to that file.

• Optional: A nicer user interface to GAP is available by using the rxvt shell via C:\gap4r4\bin\gaprxvt.bat, instead of the DOS-emulation window. (But note that the GAP Group cannot provide any support for this shell.)

• Now, please, go back to the operation system independent steps of running some short tests and giving some feedback.

Installation in a Different Directory

It is possible to install GAP in another directory. To do this you can use the start script provided in bin\gap.bat for running GAP. But before you have to edit that file and change the paths to your chosen location of the installation.

Memory issues

By default, the ``cygwin'' environment we use limits a program's workspace to 384 MB of memory. To increase this limit, it is necessary to edit the Windows registry.

*WARNING:* Editing the registry is the Windows equivalent of open heart surgery. Do not attempt this change if you have no previous experience in doing this. The web page www.cygwin.com/cygwin-ug-net/setup-maxmem.html gives further details for the current version of Cygwin (not the one supplied with GAP 4.4.12).

Before changing the entries, you might have to run GAP once first to create the appropriate registry keys.

The shell script usemem.bat in the bin directory sets a registry entry

/HKEY_LOCAL_MACHINE/Software/Cygnus Solutions/Cygwin/heap_chunk_in_mb

to decimal 1024.

If you prefer to do the change by hand, open `regedit' and go to the `Cygwin' Key listed above. Then choose `new value' and add `heap_chunk_in_mb'. `Modify' it to contain decimal 1024.

The above method was known to work for Windows XP at the time of the GAP 4.4.12 release. If it does not work for your installation of Windows XP of if you are using Windows Vista or Windows 7, see the webpage http://www.cs.st-andrews.ac.uk/~alexk/gap/win7mem/ by Alexander Konovalov for further instructions.