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loading raw images
From: |
Wolf Lammen |
Subject: |
loading raw images |
Date: |
Thu, 25 Mar 2004 21:10:43 +0100 (MET) |
Hi Alex,
A disk image of a bootable partition, given as an ordinary file, is
generally not bootable. Though GRUB can be instructed to load (at least the
first
sectors of) such a file into memory and start it, it is almost certain, that the
started image, erroneously assuming it still resides on a disk in its
original position, tries to access the disk and load further parts of itself
using
false addresses.
Boot loaders (like GRUB) use 'fire and forget' strategies: After having
started the very first beginning of an OS, their task is fulfilled, and the boot
loader code is not called again.
On the contrary, emulators like bochs run an image in a sandbox and
intercept all calls to a disk, redirecting the call to the proper parts of the
image
file. The emulator lives (and has to live) until the started image finally
shuts down.
The difference in task and technique is really colossal, so I personally do
not expect GRUB featuring such extensions soon.
Wolf Lammen
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