PC/MS DOS
In the DOS era overlays were popular because the operating system and many of the computer systems it ran on lacked virtual memory and had very little RAM by current standards — the original PC had between 16K and 64K depending on configuration. "Several DOS linkers in the 1980s supported in a form nearly identical to that used 25 years earlier on mainframe computers." Binary files containing memory overlays had a defacto standard extension, .OVL. This file type was used among others by WordStar and dBase. The GFA BASIC compiler was able to produce .OVL files.
Read more about this topic: Overlay (programming)
Famous quotes containing the word dos:
“The people of the United States have been fortunate in many things. One of the things in which we have been most fortunate has been that so far, due perhaps to certain basic virtues in our traditional ways of doing things, we have managed to keep the crisis of western civilization, which has devastated the rest of the world and in which we are as much involved as anybody, more or less at arm’s length.”
—John Dos Passos (1896–1970)