# Unable to find device node for /dev/ad0s1b in /dev!



## onunix (May 21, 2011)

I've searched several threads with this same topic but none have helped so far. I have a Super Talent 16gb PATA SSD drive installed on my old Dell laptop. This is the only drive in the machine other than the CD.

Using sysinstall I see the following at the allocation menu after choosing to use the entire disk.


```
Disk name ad0
Disk Geometry   29582 cyls/16 heads/63 sectors (14559MB)

Offset     Size(ST)       End    Name    PType     Desc  Subtype  Flags
      0          63        62       -       12   unused        0
     63    29818593  29818655   ad0s1        0  freebsd      165   =
```

I chose to install the FreeBSD boot manager.

At the label menu, I choose auto defaults which look reasonable.

But on committing installation I get the above error message. Per other similar threads, I've used the live FSdisk and dd to write /dev/zero to the first and last 35 sectors. No luck.

I saw one post that said to use *gpart list* and *gpart destroy*, but *gpart list* shows no devices at all, yet fdisk in sysinstall obviously sees it.

When I rebooted from sysinstall, a FreeBSD boot menu did appear, so it must be able to write *something* to the disk.

Is it possible the hard drive is not compatible with the laptop interface? If so, why can it install the boot manager?

Thanks for any advice you may have.


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## wblock@ (May 21, 2011)

Are you pressing W to write out the disk information?  Don't do that, sysinstall will do it itself.


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## nilsgecko (May 22, 2011)

I just had this same problem today installing and re-installing on a Thinkpad Laptop I acquired.  I received the same error, so I eventually not only deleted the disk contents with an OpenRC Cd using Gparted, http://www.sysresccd.org/Main_PageI also booted a utility off the disk called "DBAN" (at the boot menu enter in dban and press Enter) which I used to basically wipe the disk, now it is working.

I believe the error is caused at times when there is still some kind of residual information on the disk, and the installer gets confused or something.  I came to this conclusion because on debugging this error, the error message read something like


```
DEBUG encountered swap in /dev/ad0s1b in /dev
```


This was after I had used the Gparted tool to delete the previous FreeBSD Partitions, apparently, something was still there.  So wiping the disk in my case, helped and the installer ran fine.  Hope this helps.


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## wblock@ (May 22, 2011)

If that's the cure, you should only have to zero the first few blocks.  GPT uses 35 blocks at the start of the drive and another 35 blocks at the end for backup.


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## onunix (May 22, 2011)

Thanks for your responses.

No, I did not press 'w' during sysinstall.

I wonder if it may have something more to do with the physical interface. I took the SSD out of the machine and attached it via an IDE to USB cable. Now sysinstall works fine and partitions the drive as it should. Of course it is now device da0 instead of ad0.

Then I plugged the partitioned drive back into the IDE slot and reran sysinstall. The fdisk screen showed the same screen as I posted earlier; it reported no partitions as if the drive had never been touched. Continuing through sysinstall resulted in the same error as initially reported. 

I think I'm in over my head...


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## nilsgecko (May 22, 2011)

wblock said:
			
		

> If that's the cure, you should only have to zero the first few blocks.  GPT uses 35 blocks at the start of the drive and another 35 blocks at the end for backup.



Thanks for that info, I hadn't thought about that.  What it mostly was was me wanting to start from a clean-state.  

@onunix, try to reinitialize like I mentioned, it should work.


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