EOAHMAD%NTIVAX.BITNET@cunyvm.cuny.edu (09/25/90)
Please tell me how ATARI ST MINIX relocates memory since 68000 does not have any hardware relocation built in and ATARI ST does not have memory management unit that can do address translation necessary for relocation. Does it just disallow absolute addressing modes? It would be rather restrictive if this is the case. The same thing could be done to 8086, and RISC microprocessors such as SPARC. I'm sure there is a better way. The only alternative that I can think of is a relocating loader, but the output format for the ATARI ST MINIX must contain relocation information just like the MSDOS EXE file format. If this is the case, then the same technique can be used to break the IBM PC MINIX 64K barrier. Why wasn't it done? Despite A Tanenbaum's dislike for 8086 architecture, it has allowed him to implement memory management easily although it is limited to 64K size. Please send me comments. I had send 2 previous messages but there was not reply at all. I hope my messages managed to get through to the discussion list. Othman Ahmad, School of EEE, Nanyang Technological Institute, Singapore 2263 E-mail: EOAHMAD@NTIVAX.BITNET
killer@niksula.hut.fi (Kalle Kivimaa) (09/25/90)
In article <31483@nigel.ee.udel.edu> EOAHMAD%NTIVAX.BITNET@cunyvm.cuny.edu writes: >Please tell me how ATARI ST MINIX relocates memory since 68000 does >not have any hardware relocation built in and ATARI ST does not have >memory management unit that can do address translation necessary for >relocation. Atari Minix uses the same kind of relocation table added to files as TOS. >Does it just disallow absolute addressing modes? It would be rather No. See above. >I'm sure there is a better way. The only alternative that I can think of >is a relocating loader, but the output format for the ATARI ST MINIX >must contain relocation information just like the MSDOS EXE file format. I think this is the case. >Othman Ahmad, School of EEE, >Nanyang Technological Institute, Singapore 2263 >E-mail: EOAHMAD@NTIVAX.BITNET
HBO043%DJUKFA11.BITNET@cunyvm.cuny.edu (Christoph van Wuellen) (09/28/90)
the answer given explains how STATIC relocation is performed. DYNAMIC relocation (needed to support the fork system call) is avoided by using a mechanism called SHADOWING - look at the ATARI MINIX manuals for more details . C.v.W.