On 10 March 2014 10:57, Anne & Lynn Wheeler <l...@garlic.com> wrote: > I would tend to use the distinction that for the psect, a private copy > was loaded and adjusted for the specific virtual address space location > ... separately from (r/o) memory mapping the executable image with no > requirement for pre-loading and/or changing ... allowing the same exact > (r/o) executable image to concurrently occur simultaneously in different > virtual address spaces at different virtual addresses (with just a per > virtual address space private copy of the psect having been preloaded > and swizzled).
The overlay scheme used in HASP II had fixed-sized modules that were read into an available area without relocation. If the space was needed, when the first module got control again it could be loaded at a different address. But the trick was that these tasks were never preempted, so it was permissible to have a register containing an address within the module, as long as it was made relative before (loosely) calling the dispatcher, which might result in relocation. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
