This section describes the LaaTiDo utility, it's use and a background to it's creation.

Background

Although the maximum addressable memory in the 32-bit world is 4GB every process running in 32-bit Windows XP normally have access to at the most 2GB us memory for its own use not matter how much RAM memory there is in the machine as the other 2GB is locked away for the systems' internal use. The scenario in the music world where we're likely to encounter this limit is when using software samplers and plugin hosts hosting software samplers where lots of data needs to be loaded into RAM memory. Microsoft also acknowledged this problem and created a way to circumvent this problem, at least partially. By using a combination of an option in the boot configuration and an application capable of detecting this option if possible to push the limit to 3GB thus leaving 1GB to the system.

The boot option is easy to set by editing a simple file, but the problem is that not all applications we're using have support for the option. Due to the ingenious design of this feature however it's possible to make any application aware of this option without having access to the source code or having to rebuild the application.

There are a couple of tools out there that are capable of doing this, but they are all directed to developers and not end-users as end-users are not normally supposed to fiddle with these things. Nothing could be more wrong when it comes to the memory hungry music community! In order to provide an easy-to-use tool which contains some additional safety measures I wrote LaaTiDo, the LargeAddressAware Editor.

Download

LaaTiDo is available for download at http://www.musikbanken.se/laatidosetup.exe

Installation and operation

Run the installer and follow the instructions for installation. Read the knowledge base section below to find out if you're affected  by any of the issues listed there.

Expected results

On a 3GB machine you can expect to be able to use up to about 2.7GB for a process. On a 4GB machine the same number is about 2.9GB.

Knowledge base

1. Ensure that you have Windows XP Service Pack 2 before adding the /3GB boot option. Boot problems causing the machine to fail may occur if Service Pack 2 is not applied on certain machines. To avoid the possibility of a mistake regarding this, ensure to follow the guidelines and copy the line in boot.ini.
2. Samplitude which is currently not LargeAddressAware is not possible to patch as the copy protection checks the exe file for every single bit change..

Links

• I wrote an in-depth discussion on the topic for Virtual Instruments Magazine and it is available in the June/July 2006 issue.

• I also wrote a guidelines post for Vienna Symphonic Library regarding memory configuration in relation to their Vienna Instruments line of products.
• Microsoft MSDN article on LargeAddressAware.
• Microsoft MSDN article on /3GB

Last updated: June 22, 2006