Date: Sat, 11 Nov 1995 14:24:59 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: questions@freebsd.org Subject: Re: Any info on Win95 boot process ? Message-ID: <199511112124.OAA08077@phaeton.artisoft.com> In-Reply-To: <199511111319.OAA11756@labinfo.iet.unipi.it> from "Luigi Rizzo" at Nov 11, 95 02:19:37 pm
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> After trying out Samba... > > Does anyone have details on the boot process of Windows95 ? We > would like to set up a boot eprom for Win95, using the FreeBSD boot > eprom code as a starting point. > > Depending on how the bootstrap is carried on in Win95, the thing > might be very easy or very hard to do. It would be. You could do it, but it would take Level 2 or better access to materials. You would need at the very least the MSVC2.0, the SDK, and the DDK. The main problem isn't the bootstrapping, it's the switch to protected mode. Basically, the thing switches from a non-protected mode FAT FS (that you could intercept at the INT 21 or INT 13 level in your boot code, per your second scenario) to VFaT, which you couldn't unless you predisable 16 bit I/O, etc. Even then it's rather iffy when the thing first comes up; basically, you'd probably have to reimplement VFAT to make it happy, since it will call the VFAT FSD entry point FS_OpenFile with a NULL pir->ir_ppath to indicate that it's reestablishing a handle for a file that was open before it went into protected mode. > + otherwise, a small floppy image should be loaded somewhere in memory, > [so that the network card is not in use afterwards], the disk > read&write routines are hooked to some code which accesses this image > instead, and control is transferred to the standard boot code. > After booting has completed, the area of memory containing the floppy > image is freed and returned to the pool of usable RAM. > > The second approach is harder, because you have to find out how to > allocate memory in such a way that the floppy image is not overwritten > during the (early) stages of the boot process. It's also the onlt one with a chance of success. 8-(. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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