The newly (May 2003) named element
darmstadtium has the abbreviation DS. Previously the
element 110 was referred to as
ununnilium.
Double Sided floppy disks. Double sided disks can hold 720 KB of data, 2x what it could hold before the technology was implimented. Don't know if you have a DS disk? There should be large DS lettering near or on the sliding cover that protects the disk.