[solved] no operation system found, but partitions seem to be ok

pseb · 2011-09-12 15:53:35

hi,
left my computer running for some hours (so nothing unusual), but when I came back screen was off, nothing happening, so I pressed the reset button. on reboot BIOS complained about finding no operation system. so i started from an ubuntu live cd. at first i thought the hard drive crashed, but i can access all partitions (root, home) without any problem, and (thankfully) all the data is still there. fsck-ing the partitions produced no error.
has anyone any idea what's wrong? or what i could do to get more info?
thx,
pseb

Last edited by pseb (2011-09-12 17:08:47)

fsckd · 2011-09-12 15:59:05

What boot loader?

jakobm · 2011-09-12 16:01:26

Please check: partition table, boot flag, mbr intact
What have you written to the mbr and which bootloader are you using?

skodabenz · 2011-09-12 16:04:29

pseb wrote:

hi,
left my computer running for some hours (so nothing unusual), but when I came back screen was off, nothing happening, so I pressed the reset button. on reboot BIOS complained about finding no operation system. so i started from an ubuntu live cd. at first i thought the hard drive crashed, but i can access all partitions (root, home) without any problem, and (thankfully) all the data is still there. fsck-ing the partitions produced no error.
has anyone any idea what's wrong? or what i could do to get more info?
thx,
pseb

Did you have any external USB drive plugged in when you switched on the system? Some BIOSes have the nasty issue to overwriting the MBR of boot disk with that of a non-boot disk, upon boot failure of any external drive. If you are using syslinux, check whether you have active/boot flag enabled in your /boot partition.

pseb · 2011-09-12 16:16:07

thx for your quick responses!

i'm using grub.
@jakobm: checked the partition table with fdisk /dev/sda, seems fine so far, bootflag is unchanged. or is there any better way to check? and: how can i check whats written in the mbr?
@skodabenz: yes, i had an external usb-drive plugged in.

pseb · 2011-09-12 17:08:31

ok, after reinstalling grub from chroot my system works again. thank you for your hints, you saved my day

jakobm · 2011-09-12 17:14:04

To not let your question unanswered:

pseb wrote:

how can i check whats written in the mbr?

Read the first 440B from your disk and compare it with grub's stage 1, e.g.

dd if=/dev/sda bs=440 count=1 of=mbr
diff <(hexdump mbr) <(hexdump /usr/lib/grub/i386-pc/stage1)

pseb · 2011-09-12 17:18:38

ah, good to know. i'll save that for later (though, of course , i will hopefully not need it ^^)

Arch Linux

#1 2011-09-12 15:53:35

[solved] no operation system found, but partitions seem to be ok

#2 2011-09-12 15:59:05

Re: [solved] no operation system found, but partitions seem to be ok

#3 2011-09-12 16:01:26

Re: [solved] no operation system found, but partitions seem to be ok

#4 2011-09-12 16:04:29

Re: [solved] no operation system found, but partitions seem to be ok

#5 2011-09-12 16:16:07

Re: [solved] no operation system found, but partitions seem to be ok

#6 2011-09-12 17:08:31

Re: [solved] no operation system found, but partitions seem to be ok

#7 2011-09-12 17:14:04

Re: [solved] no operation system found, but partitions seem to be ok

#8 2011-09-12 17:18:38

Re: [solved] no operation system found, but partitions seem to be ok

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