Date: Fri, 11 Jul 2014 17:50:43 -0500 From: "Matthew D. Fuller" <fullermd@over-yonder.net> To: Nathan Whitehorn <nwhitehorn@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: Boot loader too large Message-ID: <20140711225043.GH50976@over-yonder.net> In-Reply-To: <53C06780.8010702@freebsd.org> References: <CANuCnH9K_wSPkgrAzujDG5M72Uvuvj0ooNN%2BFFLUCFsvv6b7Ow@mail.gmail.com> <CANuCnH_TYf0e_4xgju5QgR4bKJ_j1td9JrfADuncR4RXu7ssnQ@mail.gmail.com> <201407111345.25225.jhb@freebsd.org> <53C06780.8010702@freebsd.org>
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On Fri, Jul 11, 2014 at 03:38:56PM -0700 I heard the voice of Nathan Whitehorn, and lo! it spake thus: > > I don't honestly remember where that number came from. It's at line > 72 of usr.sbin/bsdinstall/partedit/partedit_x86.c. If 128 works > better, I'm happy to change it, but it would be nice to know what > the actual bounds here are before putting in a new arbitrary number. src/sys/boot/i386/pmbr/pmbr.s says ------------- next_boot:. incl (%si). . . # Next LBA . . adcl $0,4(%si) . . mov %es,%ax. . . # Adjust segment for next . . addw $SECSIZE/16,%ax. . # sector . . cmp $0x9000,%ax.. . # Don't load past 0x90000, . . jae err_big. . . # 545k should be enough for . . mov %ax,%es. . . # any boot code. :) ------------- (err_big being printing the "Boot loader too large" message). Though 0x90000 is actually 576k, not 545, but presumably there's some other adjustment lopping off bits somewhere; that's 62 sectors diff. Regardless, I settled on 512k for my boot partitions (after finding the above error when I previously decided "it's a few dozen k, I'll just set aside a meg to be safe" and then discovered the whole "not-booting" thing that caused. -- Matthew Fuller (MF4839) | fullermd@over-yonder.net Systems/Network Administrator | http://www.over-yonder.net/~fullermd/ On the Internet, nobody can hear you scream.
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