<operating system> (DOS) The original disk operating system from IBM.
DOS was the low-end OS of choice on the IBM 360, the high-end system was called just "OS". DOS had a smaller kernel and less functionality than OS and could run on the typical 32K 360/30 and 64K 360/40 class machines.
DOS was a successor to TOS.
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Nearby terms: disk farm « diskless workstation « disk mirroring « Disk Operating System » disk operating system » disks » disk striping