69 DOS definitions

Disk Operating System 
Defective Operating System 
Denial of Service 
Department of State 
Defunct Operating System 
dead operating system 
Dad over shoulder 
day of supply 
density of states 
Dozing Off Soon 
date of separation 
Days Of Supply 
Digital Operating System 
Disc Operating System 
Date of Service 
day of surgery 
Degree of sensitization 
Department of Space 
Detailed Operations Scenario 
Development Open Server 
Direct Operating System 
Director of Ordnance Services 
Distributed Operating System 
Doctor of Ocular Science 
Due On Sale Clause 
Data Oriented Services 
Data-Output System 
date of surgery 
daughter of sevenless 
Days on Stream