using knoppix tohd=/dev/sda1 boot option when sda1 is an external USB HD

**carolus** · 02-09-2014, 03:54 AM

knoppix tohd=/dev/sda1 boot option does not seem to work when /dev/sda1 is an external USB hard drive. It this the expected behavior?

**Werner P. Schulz** · 02-09-2014, 12:22 PM

'Are you sure, your external drive is '/dev/sda' and the partition is '/dev/sda1'? Please boot Knoppix again without the cheatcode "tohd=/dev/sda1" an tell us the output from

Code:

blkid

and

Code:

fdisk -l

**carolus** · 02-09-2014, 03:47 PM

I've already checked this, but I'll try again after the machine finishes a 24-hour memory check. What log files should I look at then? The machine is old and may have intractable hardware problems, but I can use it a little longer if I can get Knoppix running with persistence. It boots reliably only from the DVD drive. (The external USB drive is the only other functioning drive on the machine, and it comes up as sda.)

**carolus** · 02-09-2014, 06:39 PM

Tried again. The USBHDD is installed as sda. There is nothing obvious to the untutored eye in the dmesg methods that describe detecting and installing sda. There seem to be no messaged from Knoppix in /var/log. But the files are simply not copied to the USBHDD with option tohd.

If tohd is known to work for USB hard drives, then I will simply write this off to hardware failure in an old computer.

**Werner P. Schulz** · 02-09-2014, 08:01 PM

What you want to install is the "Poor man's install" as I described it at
http://knoppix.net/wiki/Category:Har...e_Installation
and I never heard from other peoples about problems using an USB drive for this method.

But it's a little tricky to boot this installaton. If your BIOS can boot with the USB drive, why not use "Flash disk Install to HD" or "HD Install"?

**carolus** · 02-10-2014, 01:30 AM

If your BIOS can boot with the USB drive, why not use "Flash disk Install to HD" or "HD Install"?

That works fine when it works, but more often than not, I get messages saying that the boot medium is defective (though the flash drive works consistently on another machine, and I get the same messages about defective medium using a perfectly good Puppy Linux bootable flash drive). The capability to boot from USB was added only in the final upgrade version for that BIOS before it was discontinued, and so any bugs would have gone unfixed. I can only boot reliably from the DVD drive, so it would be nice to boot from the DVD and then transfer control to the external drive. But I guess that box is headed for the junk heap.

**Werner P. Schulz** · 02-10-2014, 09:17 AM

You can create a Knoppix boot-CD or download a bootonly CD from the Knoppix mirrors.

**Blacksimon** · 02-10-2014, 01:15 PM

Are you sure you mean tohd and not fromhd option ?

**carolus** · 02-10-2014, 05:04 PM

Originally Posted by Werner P. Schulz

You can create a Knoppix boot-CD or download a bootonly CD from the Knoppix mirrors.

But I require persistence as well, have only an external USB hard drive to work with, and no USB boot.

**carolus** · 02-10-2014, 05:15 PM

Originally Posted by Blacksimon

Are you sure you mean tohd and not fromhd option ?

Yes. I first tried these options on another computer in a virtual machine to see how they work. They work as advertised on a virtual hard drive. In contrast, on my target machine, with only an external USB hard drive, tohd fails to copy the knoppix files to the external hard drive. Apart from ignoring the boot option, it boots normally, with no relevant messages.

Since the hard disk is probably installed earlier in the boot process than USB devices, it seems possible that tohd might not work with USB devices.