With Save as you can write the current database to disk.
The current database may be nameless.
You will be asked to provide a name.
With 
and 
you can step through names entered earlier.
With TAB you can abort the Save as operation.
The descriptor will be written to name.des,
and the data will be written to name.dat.
The previous descriptor and/or data (if any) are moved to
name.des.save and name.dat.save.
The format of these files is described in the section
on implementation (sec. 5).
If the current database is nameless, Save as will make name the name of the current database. If the current database has a name and is marked modified, Save as will not mark the current database as not modified.