From DSL Wiki
Busybox is a smaller toolchain for linux and is used by defalt in Damn Small Linux. Busybox doesn't have many of the options for common toolchain commands that the GNU-Utils set does. However it does have a much small memory requirement which is essential when you are trying to fit an entire operating system into 50MB.
How it Works []
Busybox works as one big executable called by multiple symlinks. Busybox then changes how it works based on which symlink called it. Having one executable file saves space by not having to have the multiple headers and data bits that go with every executable file.
Upgrading Tool options (Moving from Busybox to GNU-Utils)
GNU-Utils is a toolchain with full featured versions of some of the more commonly used applications in busybox. Some of these are required for enabling Apt-Get/Synaptics. When you upgrade to the GNU-utils, some of the busybox symlinks will be replaced by their respective gnu-util counterparts. The busybox executable is still available, and the old busybox version of a gnu-util application can be called by running "busybox [util name] [options]" (i.e.: busybox mount)
The Easy Way
Upgrading your toolchain from busybox to semi-gnu is simple. Go to your menu and go to apps. Then to tools -> Upgrade to GNU Utils. This will fetch the gnu-utils.dsl extension from the dsl server and install it.
The Not so Easy Way
If you can't or don't want to use the online tool you can go to the mydsl repository and download the gnu-utils.dsl file directly. Then add it to your mydsl file (remaster, frugal, or hard disk install) or install it manually each time you need to use it (this works on all runs).
Upgrading Tool options (coreutils.uci- Full GNU-Utils)
Upgrading to GNU-Utils does not give you all the full features applications that are available. To upgrade to the full utilities (more then most users will ever need), you can use the "coreutils.uci" extension provided by mikshaw. This is available in the MyDSL repository. Of note, this extension is still in the TESTING section, and should be treated as such (But send feedback if it works, so it can eventually be moved out of testing).
Core-Utils MyDSL info[]