Hi, >> 22:23 <@aljen> you mean ds:si pointing to selected partition entry in >> mbr when jumping into vbr's code ? >> 22:23 < mmu_man> yup > > Could have told you about that. At least some MBRs leave ds:si to point to > the entry, which seems a random occurrence rather than an intentional > interface. I think almost no one uses it.
As far as I remember, the MS DOS 7.x / Windows 9x boot sectors did use it and it is in fact intentional there. > In a boot sector, you could attempt to use that information; if so, > verifying that the byte at address ds:si contains the value 80h (or at the Which is, again as far as I remember, what Win9x did. If you really want to know, you can certainly find an annotated list of the machine code of that very widespread boot sector ;-) > very least has the highest bit set; that is, a value >= 80h) helps with > finding out whether the MBR supports this "interface". MBRs are expected > to relocate to 60:0 or linear 600h, so another verification would be to > check that ds:si then points to one of the entries in the partition table > copy there. Not all MBRs do that, but it is yet another popular convention. Eric ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
