Adjective
DSDD (not comparable)
(computing, of a diskette) Initialism of double-sided, double density.
In many cases, the media are marketed without any indication of the end user capacity, as for example, DSDD, meaning double-sided double-density. Source: Internet
DSDD drives were backwards compatible; they could read and write SSDD floppies. Source: Internet
PC DOS version 1.00 supported only 160 kB SSDD floppies, but version 1.1, which was released nine months after the PC's introduction, supported 160 kB SSDD and 320 kB DSDD floppies. Source: Internet