[comp.arch] loading

jhallen@wpi.wpi.edu (Joseph H Allen) (01/16/90)

In article <380@bambam.UUCP> bpendlet@bambam.UUCP (Bob Pendleton) writes:
>From article <7413@drilex.UUCP>, by dricejb@drilex.UUCP (Craig Jackson drilex1):

>> But relocatibility
>> would be essential for almost any Unix-like operating system, and I would

>My conclusion is that you've never heard of a relocating loader. I

This reminds me, has anyone even made a linker and/or loader system that can
load into multiple fragments of a non-MMU'd memory?  I'm not sure if this can
be done with variable size fragments but it should work if a block size is
defined.  Also, it can probably only work with the code, not the data.  It
would be like a PDP-8...

peter@ficc.uu.net (Peter da Silva) (01/17/90)

> This reminds me, has anyone even made a linker and/or loader system that can
> load into multiple fragments of a non-MMU'd memory?

Both the Amiga and the Macintosh do this. I believe the Mac uses base
registers and call gates, so it's technically *got* an MMU and it's the
runtime system that's doing the work, not the loader. The Amiga loader
actually does the final linking step: multiple references are resolved
and the in-core image is modified. You can have as many such chunks as you
can stand.
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pkr@maddog.sgi.com (Phil Ronzone) (01/18/90)

In article <6792@wpi.wpi.edu> jhallen@wpi.wpi.edu (Joseph H Allen) writes:
>This reminds me, has anyone even made a linker and/or loader system that can
>load into multiple fragments of a non-MMU'd memory?

Yeah, ancient IBM OS/MVT OS/MFT had a "scatter" loader. Boy, could you ever
fragment memory and wedge your machine with it. Ugly.



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Phil Ronzone   Manager Secure UNIX           pkr@sgi.COM   {decwrl,sun}!sgi!pkr
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