Analysis of information sources in references of the Wikipedia article "Overlay (programming)" in English language version.
This lets you run programs which are, in effect, much larger than the amount of memory in your computer.
{{cite book}}: |magazine= ignored (help){{cite book}}: |work= ignored (help) (52 pages){{cite book}}: |work= ignored (help) (8 pages)Version 1.1 has a new dynamic Memory Management System (dMMS) that handles overlays more efficiently: the product requires less memory, which results in more applications space availability. […] The product's lower memory requirements of only 450K of RAM provide improved network support because supplemental hardware memory is no longer required to support networks. […] By speeding up areas of dBASE IV that are overlay-dependent, the new dMMS improves performance when working at the Control Center and in programs that use menus and windows.(5 pages)
[…] The reason to suspect such difference is that version 3.2x also supported CP/M-86 (the overlays are identical between DOS and CP/M-86, only the main executable is different) […] the .OVR files are 100% identical between DOS and CP/M-86, with a flag (clearly shown in the WordStar 3.20 manual) switching between them at runtime […] the OS interface in WordStar is quite narrow and well abstracted […] the WordStar 3.2x overlays are 100% identical between the DOS and CP/M-86 versions. There is a runtime switch which chooses between calling INT 21h (DOS) and INT E0h (CP/M-86). WS.COM is not the same between DOS and CP/M-86, although it's probably not very different either. […]
[…] A PRL file is a relocatable binary file, used by MP/M and CP/M Plus for various modules other than .COM files. The file format is also used for FID files on the Amstrad PCW. There are several file formats which use versions of PRL: SPR (System PRL), RSP (Resident System Process). LINK-80 can also produce OVL (overlay) files, which have a PRL header but are not relocatable. GSX drivers are in PRL format; so are Resident System Extensions (.RSX). […][3]
This lets you run programs which are, in effect, much larger than the amount of memory in your computer.
{{cite book}}: |magazine= ignored (help){{cite book}}: |work= ignored (help) (52 pages){{cite book}}: |work= ignored (help) (8 pages)[…] A PRL file is a relocatable binary file, used by MP/M and CP/M Plus for various modules other than .COM files. The file format is also used for FID files on the Amstrad PCW. There are several file formats which use versions of PRL: SPR (System PRL), RSP (Resident System Process). LINK-80 can also produce OVL (overlay) files, which have a PRL header but are not relocatable. GSX drivers are in PRL format; so are Resident System Extensions (.RSX). […][3]
[…] The reason to suspect such difference is that version 3.2x also supported CP/M-86 (the overlays are identical between DOS and CP/M-86, only the main executable is different) […] the .OVR files are 100% identical between DOS and CP/M-86, with a flag (clearly shown in the WordStar 3.20 manual) switching between them at runtime […] the OS interface in WordStar is quite narrow and well abstracted […] the WordStar 3.2x overlays are 100% identical between the DOS and CP/M-86 versions. There is a runtime switch which chooses between calling INT 21h (DOS) and INT E0h (CP/M-86). WS.COM is not the same between DOS and CP/M-86, although it's probably not very different either. […]
Version 1.1 has a new dynamic Memory Management System (dMMS) that handles overlays more efficiently: the product requires less memory, which results in more applications space availability. […] The product's lower memory requirements of only 450K of RAM provide improved network support because supplemental hardware memory is no longer required to support networks. […] By speeding up areas of dBASE IV that are overlay-dependent, the new dMMS improves performance when working at the Control Center and in programs that use menus and windows.(5 pages)