Content deleted Content added
Matthiaspaul (talk | contribs) →Further reading: improved ref |
Matthiaspaul (talk | contribs) →Historical use: CE |
||
Line 55:
==Historical use==
IBM introduced the concept of a ''chain job''<ref name="IBM_1963_FORTRAN"/>
in [[FORTRAN II]]. The program had to explicitly call the CHAIN subroutine to load a new link,▼
▲The program had to explicitly call the CHAIN subroutine to load a new link,
and the new link replaced all of the old link's storage except for the Fortran COMMON area.
Line 66 ⟶ 65:
In the [[home computer]] 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 [[IBM PC]] had between 16K and 64K, depending on configuration. Overlays were a popular technique in [[Commodore BASIC]] to load graphics screens.<ref name="Butterfield_1986"/>
"Several [[DOS]] linkers in the 1980s supported [overlays] in a form nearly identical to that used 25 years earlier on mainframe computers."<ref name="Levine_2000"/> [[Binary file]]s containing memory overlays had a de facto standard extension, '''.OVL'''. This file type was used among others by [[WordStar]], [[dBase]], and the ''Enable'' DOS office automation software package from [[Enable Software, Inc.]] The [[GFA BASIC]] compiler was able to produce .OVL files.
== See also ==
| |||