Editing DOS/360 and successors (section)

{{Short description|IBM mainframe operating system designed for use with smaller machines}}
{{About|the family of operating systems for IBM System/360 computers||DOS (disambiguation)}}
{{History of IBM mainframe operating systems}}
'''Disk Operating System/360''', also '''DOS/360''', or simply '''DOS''', is the discontinued first member of a sequence of [[operating system]]s for [[IBM System/360]], [[System/370]] and later [[IBM mainframe|mainframes]]. It was announced by [[IBM]] on the last day of 1964, and it was first delivered in June 1966.<ref>{{cite book |first1=E.W. |last1=Pugh |first2=L.R. |last2=Johnson |first3=John H. |last3=Palmer |title=IBM's 360 and early 370 systems |date=1991 |publisher=[[MIT Press]] |location=Cambridge, MA and London |isbn=0-262-16123-0}}<br/>&ndash; extensive (819&nbsp;''pp.'') treatment of IBM's offerings during this period</ref>  In its time, DOS/360 was the most widely used operating system in the world.<ref>Pugh, ''op. cit., p.'' 331 &ndash; most widely used OS</ref>