- In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and 47.8 Ma, is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the lower Eocene.
- DOS (Wikipedia)
DOS (/dɒs/, /dɔːs/) is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft’s MS-DOS, both of which were introduced in 1981. Later compatible systems from other manufacturers include DR-DOS (1988), ROM-DOS (1989), PTS-DOS (1993), and FreeDOS (1998). MS-DOS dominated the IBM PC compatible market between 1981 and 1995.