A world image, also called a band, is a file that contains a
complete Scheme system, perhaps additionally including user application
code. Scheme provides a method for saving and restoring world images.
The method writes a file containing all of the Scheme code and data in
the running process. The file runtime.com that is loaded by the
microcode is just such a band. To make your own band, use the procedure
Causes a band to be written to the file specified by filename. The optional argument identify controls what happens when that band is restored, as follows:
Start up in the top-level REPL, identifying the world in the normal way.
Do the same thing except print that string instead of ‘Scheme’ when restarting.
Restart exactly where you were when the call to
performed. This is especially useful for saving your state when an
error has occurred and you are not in the top-level REPL.
#t, except that the runtime system will not perform
normal restart initializations; in particular, it will not load your
To restore a saved band, give the --band option when starting
Scheme. Alternatively, evaluate ‘(disk-restore filename)’,
which will destroy the current world, replacing it with the saved world.
The argument to
disk-restore may be omitted, in which case it
defaults to the filename from which the current world was last restored.