>Date: Tue, 18 Jan 2000 16:33:17 -0800
>From: Phlatlyn <phlatlyn@pacbell.net>
>
>I am now having yet another strange problem. When I compile a kernel on
>my P60 everything seems fine,but when I try to boot from it responds
>
>2637824read text: Input/output error
>boot: sd0a:netbsd: Input/output error

I had the same problem on one of my systems a while back.

The problem was that when I had installed the system (by hand, before
sysinst existed) I had assumed it was OK to start partitions 'a' and
'c' at offset 0.

At one time that seemed to work OK, but at some point something must
have changed in the boot blocks such that a valid MBR is required.

My solution was to rewrite a good MBR to the disk with fdisk, then
write a disklabel with offset 63 for those partitions (same offset as
sysinst uses), then restore the filesystem and rewrite the boot blocks
with installboot.

My disklabel now looks like this:
  a:   131072       63     4.2BSD     1024  8192    16   # (Cyl.    0*- 182*)
  b:   131072   131135       swap                        # (Cyl.  182*- 364*)
  c:  4433877       63     unused        0     0         # (Cyl.    0*- 6158*)
  d:  4446801        0     unused        0     0         # (Cyl.    0 - 6176*)
  e:  4184594   262207     4.2BSD     1024  8192    16   # (Cyl.  364*- 6176*)

And my MBR partition table looks like this:
NetBSD disklabel disk geometry:
cylinders: 6144 heads: 4 sectors/track: 180 (720 sectors/cylinder)

BIOS disk geometry:
cylinders: 276 heads: 255 sectors/track: 63 (16065 sectors/cylinder)

Partition table:
0: sysid 169 (NetBSD)
    start 63, size 4433877 (2164 MB), flag 0x80
        beg: cylinder    0, head   1, sector  1
        end: cylinder  275, head 254, sector 63
1: <UNUSED>
2: <UNUSED>
3: <UNUSED>

Hope that helps...

--
entropy