# Cannot open root device.

## Shimoda

As you can see from the image linked, the kernel cannot open my root device.

https://drive.google.com/file/d/0B04swGC2m3FhMVVQYVFpQzQ1MHVvRmN0Q21tMWZMR1VTbnl3/view?usp=sharing

I can't understand why.

I read other posts with the same problem but none has solved this.

i activated ahci in the kernel, wich is the module in use with the initramfs... but nothing changes.

lspci -k

00:1f.2 SATA controller: Intel Corporation 8 Series SATA Controller 1 [AHCI mode] (rev 04)

	Subsystem: Intel Corporation 8 Series SATA Controller 1 [AHCI mode]

	Kernel driver in use: ahci

	Kernel modules: ahci

04:00.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

05:00.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

05:03.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

05:04.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

05:05.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

05:06.0 PCI bridge: Intel Corporation Device 156d

	Kernel driver in use: pcieport

06:00.0 System peripheral: Intel Corporation Device 156c

fdisk -l /dev/sda

Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors

Units: sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disklabel type: gpt

Disk identifier: 8E72EF57-9C65-4F8B-9769-EA8A054A1B94

Device          Start        End    Sectors   Size Type

/dev/sda1          40     409639     409600   200M EFI System

/dev/sda2      409640 1077016663 1076607024 513.4G Apple HFS/HFS+

/dev/sda3  1077018624 1077280767     262144   128M Microsoft basic data

/dev/sda4  1369756104 1371025639    1269536 619.9M Apple HFS/HFS+

/dev/sda5  1371027456 1371029503       2048     1M Linux filesystem

/dev/sda6  1371029504 1551327231  180297728    86G Linux filesystem

/dev/sda7  1551327232 1559029759    7702528   3.7G Linux swap

/dev/sda8  1559029760 1953523711  394493952 188.1G Microsoft basic data

/dev/sda9  1077280768 1369755647  292474880 139.5G Linux filesystem

Partition table entries are not in disk order.

(besides this... what are all that ram devices?)

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## Roman_Gruber

please append a correct root option.

This clearly states, that the kernel is unable to see your root partition.

Usually you need to add to grub.cfg something like, and of course adapted to your scenario, these are from my box, only works in my setup

You have to read how you define this line

        set root='hd0,gpt2'

You need to adapt this to your scenario, i have written human readable explanation ..., you need to google and than fill out.

linux /kernel_name rootfstype=root_file_system_type keymap=keyboard_layout init=/linuxrc ro real_root=device_of_root_partition 

Other possibilities include that you did not specifiy the software pieces for your hardware controller and the root file-system support

cannot open root device, or unknown block 0/0

you need to comprehend how partitions are named, and than append the right dataset to grub / assuming you use grub2 (one of many choices)

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## Shimoda

I'm really sorry.

This is the correct image:

https://drive.google.com/file/d/0B04swGC2m3FhUFp1Y1NoOUcxc3c/view?usp=sharing

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## NeddySeagoon

Shimoda,

You have asked the kernel to use /dev/sda9 as root.  As it can't find /dev/sda9, its listed all the block devices it can see.

16 ram device, no HDD partitions and no optical media.

Together with the unknown-block(0,0) this usually means that some of the HDD code is missing from the kernel.

Please tell us how you configured and installed your kernel.

Also make friends with wgetpaste and put your kernel .config file onto a pastebin site.

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## Shimoda

Solved.

I had to select SCSI disk support in the kernel.

Thank you.

(And thanks to #gentoo channel)

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