OS/4

{{Short description|Discontinued UNIVAC computer operating system}}

{{For|the operating system known as OS4|Computer Automation}}

OS/4 is a discontinued operating system, introduced in 1972, from UNIVAC for their 9400, 9480, and 9700 computer systems. It is an enhanced version of UNIVAC's 9400 Disc Operating System. OS/4 is a disc-resident system requiring 64 KB of main memory, two disc drives, a punched-card reader and a printer. The resident memory footprint is approximately 24 KB.{{cite web |title=UNIVAC 9700 |url=http://bitsavers.org/pdf/univac/9x00/datapro/70C-877-03_7201_UNIVAC_9700.pdf |website=Bitsavers |publisher=Datapro |access-date=April 7, 2023}}

UNIVAC intended to replace OS/4 with a new system known as OS/7; however, OS/7 development was discontinued in 1975 when the 9700 was made part of the new UNIVAC Series 90 line as the 90/70.{{cite news |title=UNIVAC 90/60,90/70, and 90/80 |url=http://bitsavers.informatik.uni-stuttgart.de/pdf/univac/series_90/datapro/70C-877-06_7609_UNIVAC_90-60_70_80.pdf |access-date=Aug 24, 2018 |work=Datapro |date=September 1976}}{{cite news |title=Univac 9000, Series 70 Sites Promised Help Moving to VS/9 |url=https://books.google.com/books?id=nMHHJQxdDHYC&pg=PA11 |access-date=Aug 24, 2018 |work=Computerworld |date=November 26, 1975}}