boot hangs after install 4.8

Rob Lahaye lahaye at
Thu Jul 3 19:46:18 PDT 2003

Toomas Aas wrote:
>>From:          Rob Lahaye <lahaye at>
>>>>I have just installed FreeBSD 4.8 on a PC. Only FreeBSD, no other OS.
>>>>The installation goes all well; I exit at the end and the PC boots.
>>>>Immediately after the BIOS stuff, I get the first FreeBSD prompt:
>>>>   F1  FreeBSD
>>>>   Default: F1
> Snip...
>>FDISK Partition Editor (with "A = Use Entire Disk"):
>>	DISK Geometry:  21858 cyls/34 heads/54 sectors = 40131288 sectors (19595MB)
>>	Offset  Size(ST)     End     Name  PType       Desc  Subtype    Flags
>>	0          54         53        -      6     unused        0
>>	54   40131234   40131287    ad0s1      3    freebsd      165    C
> I suspect you need to set ad0s1 slice bootable (using S key in fdisk screen).
> Flags should be CA, not simply C.

I did following:

1) Installed RedHat 8.0. I created a brand new partition table with ext2 file system etc.
    All this went well and no problems with booting from harddisk after installation.
    Then I knew that there was no fundamental problem with booting from my harddisk.

2) Next again installed FreeBSD, following your 'set bootable' advice above.
    So I erased the Linux Partition table, and replace that by "A = Use Entire Disk"
    for FreeBSD:

	DISK Geometry:  2654 cyls/240 heads/63 sectors = 40128480 sectors (19593MB)
	Offset       Size(ST)        End     Name  PType       Desc  Subtype    Flags

	       0         63         62        -      6     unused        0
	      63   40128417   40128479    ad0s1      3    freebsd      165    CA
	40128480       4023   40132502        -      6     unused        0

Most remarkable here: the DISK Geometry is now different from my previous FreeBSD
installations! It has now changed
   from " 21858 cyls/34 heads/54 sectors = 40131288 sectors (19595MB)"
   to   " 2654 cyls/240 heads/63 sectors = 40128480 sectors (19593MB)"

And you won't believe it: now everything works!


My explanation:
	the previous disk geometry was not correct (although Mandrake Linux was
running more or less OK on this PC). Anyway, FreeBSD could not boot because of the wrong
disk geometry. By installing RedHat Linux 8.0, somehow the disk geometry automagically
got adjusted to the correct values. The next FreeBSD installation thus went on without
a hitch.....Does all that make sense?

	how do I know a disk geometry won't work, or won't work for booting the system?
Can I tell FreeBSD to also do this 'automagical' resetting of the disk geometry, similar
to what RedHat install has done?

Thanks Toomas for guiding me along this path!!


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