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Re: Problem installing Slink on UDB/Multia



On Thursday, 13 May, Nathan P. Hawkins III wrote:
> 
> On Fri, 14 May 1999, Martin Lucina wrote:
> > Also note that SRM/aboot IIRC will eat a lot (4.5mb?) of memory.
> 
> Maybe some clever person with time on their hands will do something about
> that. Seems to me that something more like SRM would be nice. For that
> matter, what's wrong with actually using SRM itself?
> 

Itself - you mean, instead of SRM/aboot?  There is no difference.  Aboot
is just a tiny layer which does not take up any resources once the control
is passed to the kernel.

To summarise briefly:

 * SRM is not available on all platforms, neither is MILO.

 * SRM eats much more memory than MILO.  On my machine, it's about 1.5 Mb
   for SRM and slightly less than 0.5 Mb for MILO.  This is probably
   irrelevant on these modern 256 Mb machines, but still makes me a bit
   unhappy about the wasted memory.  Just think about it: you run Linux
   for months non-stop, and what does it preserve so carefully all this
   time in a far corner of its high-tech semiconductor memory?  OpenVMS
   PALcode!

 * SRM's PALcode is generally better than the MILO's one, although in
   most cases this is not noticeable.  Three notable differences are:
   - interrupt processing: MILO does not pass the interrupt vector to
     the kernel, making kernel do more work;
   - missing wrperfmon call in MILO prevents from using performance
     measurement tools such as Iprobe;
   - missing wtint call in MILO does not let Linux enter low-power CPU
     mode in the idle loop.
   SRM can also play highly platform-specific tricks in its PALcode.

 * When booted from SRM, the kernel has to worry about saving/restoring
   some parts of machine state.

Nikita


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