docs/61605: Improve documentation for i386 disk geometry

[Chris Pepper]

>Number:         61605
>Category:       docs
>Synopsis:       Improve documentation for i386 disk geometry
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jan 19 18:40:16 PST 2004
>Closed-Date:
>Last-Modified:
>Originator:     Chris Pepper
>Release:        FreeBSD 4.9-STABLE i386
>Organization:
>Environment:
System: FreeBSD www.reppep.com 4.9-STABLE FreeBSD 4.9-STABLE #13: Thu Nov 13 23:50:39 EST 2003 root at www.reppep.com:/usr/obj/usr/src/sys/REPPEP i386


	
>Description:
	Documentation for disk geometry (i386) is lacking.

	As described in i386/61603, sysinstall doesn't always come up with a usable disk geometry.

	The Handbook documentation on sysinstall is a bit sparse. It should mention that geometry may be guessed wrong, \\tools\\pfdisk.exe on the CD-ROM can be used to pick up workable geometry numbers from within a working DOS environment (but not a normally-running Windows XP, which won't allow the necessary device access -- boot floppy created in XP works, though).

	http://www.freebsd.org/relnotes/4-STABLE/installation/i386/trouble.html #4.2.2 claims sysinstall will figure out geometry from a preexisting DOS partition, but this didn't work for me -- perhaps because my DOS partition started at sector #63??

	I was able to boot FreeBSD from the 5.2 CD-ROM, after installing with sysinstall's bad geometry values. It seems it should be possible to install FreeBSD boot blocks at this point, without running through the whole sysinstall process, but I was unable to find any pointers to how to do so. I checked the FAQ (which says to reinstall from scratch), and the manual pages for fdisk, sysinstall, boot0cfg, and disklabel (4.9) -- is "bsdlabel -B ad0s2" the right way to go??
	
>How-To-Repeat:
	Search www.freebsd.org for "sysinstall geometry" seeking information on getting a 5.2 system to bootstrap correctly. Bang head -- do not damage desk.

>Fix:
	Mention sysinstall's good but imperfect geometry guessing in Handbook (http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/install-pre.html 2.2.3) & FAQ (http://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/install.html#GEOMETRY).

	Suggest disklabel/bsdlabel in Handbook & FAQ & http://www.freebsd.org/relnotes/4-STABLE/installation/i386/trouble.html (4.2.2) for fixing non-bootable systems installed with incorrect geometry.

	Add bsdlabel/disklabel to SEE ALSO under boot0cfg.
>Release-Note:
>Audit-Trail:
>Unformatted: