Relocation (computing)

In software development, relocation is the process of assigning load addresses for position-dependent code and data of a program and adjusting the code and data to reflect the assigned addresses. To run successfully in this environment, the relocation sections cannot be omitted by the compiler.

Unix-like systems

The Executable and Linkable Format (ELF) executable and shared library format used by most Unix-like systems allows several types of relocation to be defined.

(3 pages) (NB. Describes a relocatable hex format by Mostek.)
(8 pages) (NB. Describes a relocatable hex format by TDL.)
[https://web.archive.org/web/20170819141800/http://www.retrotechnology.com/dri/d_dri_refs.html][https://web.archive.org/web/20170819173516/http://archive.computerhistory.org/resources/access/text/2016/12/102762506-05-01-acc.pdf][https://archive.today/20170909091943/https://groups.google.com/forum/%23!msg/comp.os.cpm/TLHgIi16yTo/gupNB1ai8UQJ#!topic/comp.os.cpm/TLHgIi16yTo]. Originally presented at: (609 pages). (This "resize" method, named page boundary relocation, could be applied statically to a CP/M-80 disk image using in order to maximize the TPA for programs to run. It was also utilized dynamically by the CP/M debugger Dynamic Debugging Tool (DDT) to relocate itself into higher memory. The same approach was independently developed by Bruce H. Van Natta of IMS Associates to produce relocatable PL/M code. As paragraph boundary relocation, another variant of this method was later utilized by dynamically HMA self-relocating TSRs like KEYB, SHARE, and NLSFUNC under DR DOS 6.0 and higher. A much more sophisticated and byte-level granular method based on a somewhat similar approach was independently conceived and implemented by Matthias R. Paul and Axel C. Frinke for their dynamic dead-code elimination to dynamically minimize the runtime footprint of resident drivers and TSRs (like FreeKEYB).)
[https://archive.org/details/bitsavers_S100Micros_46725899/page/54/mode/1up][https://archive.org/details/v1n5_20230524/page/54/mode/1up] (2 pages) (NB. Describes page boundary relocation and relocating assemblers.)
[https://ethw.org/Milestones:The_CP/M_Microcomputer_Operating_System,_1974][https://www.youtube.com/watch?v=HO6IPpL0y8g] (33 pages)
(2+xiv+270+6 pages)
[https://archive.org/stream/80-microcomputing-magazine-1983-04/80Microcomputing_0483_djvu.txt][https://archive.org/download/80-microcomputing-magazine-1983-04/80Microcomputing_0483_text.pdf]
[https://archive.org/stream/80-microcomputing-magazine-1985-04/80Microcomputing_0485_djvu.txt][https://archive.org/download/80-microcomputing-magazine-1985-04/80Microcomputing_0485_text.pdf]