Adam Thornton <[EMAIL PROTECTED]> writes:
> Yes.  You save a few megabytes per image.
>
> It makes maintenance more difficult, though.

in the original virtual memory mapped paged-map implementation (that
predated DCSS, vm/370 release 3 just picked up a small subset), the
source of the system was on standard virtual machine accessed disk
that was accessed using page mapped semantics. infrastructure layered
on top could be standard filesystem semantics ... and the object
loaded could be managed with standard filesystem operation (the load
command specified both the mapping between paged mapped disk and
virtual address space as well as any sharing options ... with various
kinds of integrity rules applied).

the issue for cms then easily becomes having multiply managed kernel
image ... you create a new kernel image at a new location and update
the boot information to point to the latest kernel image location.
people booting cms after the boot pointer change get the new image,
people that had the earlier kernel image have the previous kernel
image.
http://www.garlic.com/~lynn/subtopic.html#mmap

in theory, linux kernel images and maint. could be handled in a
similar way ... just create a new boot image in a new location.

translated to conventional dcss methodology ... this requires
multiple, similarly named (say linux01-linux-05), systems. maint
process cycles thru the different names.

virtual machines then are modified to load a named system ... say
linuxredirect ... which is just a trivial piece of redirection code
which does the actual loading of named systems. the redirection code
is updated after some maint. process and the appropriate images have
been saved to available place.

--
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/

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