Hi all,
I've spent my weekend to write a boot loader able to load and run JOS from
an hard disk. My program is composed of a pre-boot (installed on
the master boot record of HD) and a loader which loads a JOS image written
on HD starting from cyl=1,hd=0,sect=1. The loader is based on etherboot
code and, till now, it ignores any disk partition. Soon, I'll patch my
loader in order to make it able to boot from an HD partition rather than
the master boot record. Using this loader I was able to start JOS with
Bochs Pentium Emulator... it seems to work, however, it was necessary to
make some patches:
1. when JOS boots, it switches to VGA mode 7 (monocrome mode). It seems
that Bochs does not like this.. I mean.. does not handle monocrome video.
Thus I've patched "head.s86" and "jjconsol.cc" in order to startup with
VGA mode 3 (80x25 color) and make character writings to 0xb8000 rather
than 0xb0000. I've also added a software cursor to jjconsol.cc.
2. in order to make JOS able to work with Bochs, the latter must have the
FPU support, so download the FPU emulator and recompile Bochs (see Bochs
home page).
3. at JOS boot, the jbHeap class calls scrubMemory() which clear the
ENTIRE extended memory. This process is too long for Bochs, thus I've
removed this call.
4. if JOS is compiled without the option -DNATIVE_CLOCK, when JOS boots
(only under Bochs), it display continuosly "notifyOfInterrupt(3):VM
corrupted. abort notify...". Anyone knows what's happen ? I think
interrupt handling needs a lot of patches.
5. The entire pre-boot/JOS load/JOS boot/start "init" process is VERY SLOW
with Bochs. It takes several minutes on a Pentium 133. However, tomorrow
I'll try a Pentium II/400.
... ok, it seems to be enough...
However, please let me know if you are interested in obtaining the JOS HD
boot loader. If yes, I'll prepare a tar.gz version which I'll post on my
web site so you can download it.
Bye, bye,
Corrado
======================================================
Eng. Corrado Santoro - PhD Student
Unversity of Catania - Engineering Faculty
Institute of Computer Science and Telecommunications
Viale A. Doria, 6 - 95125 CATANIA (ITALY)
Tel: +39 095 7382365 Fax: +39 095 7382397
EMail: [EMAIL PROTECTED]
Personal Home Page:
http://www.cdc.unict.it/~csanto
ARCA Mobile Agent Framework Home Page:
http://netra.cdc.unict.it/ARCA
======================================================
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