Got Knoppix 5.0.1 successfully booting from USB key
Knoppix 5.0.1 boots rather nicely from a USB key. It's getting easier to get it working, as the USB bugs from the previous versions have been fixed.
I have a 1GB USB key, so using the Knoppix CD was the best fit (the DVD is much too large).
Here's a rather long thread I started a while ago, about getting an older version of Knoppix up and running: http://www.knoppix.net/forum/viewtopic.php?t=23558
I've simplified that somewhat. Here's a mini-guide:
* Boot Knoppix 5.0.1 from CD and make sure it works.
Put in your USB key as soon as possible, when you see the title screen of Knoppix, so that it is sure to be found by Knoppix autodetection.
Do not use the "toram" cheatcode when booting Knoppix. The RAM copy of the CD omits the /boot directory, but we require this directory, so we can't use the RAM copy.
* Once Knoppix is up and running, open a root shell (from the penguin icon). Now, we need to find the drive letter of your USB key. It will be something like /dev/sda, /dev/sdb, /dev/sdc, and so on. Be very careful and make absolutely sure you have the drive letter correct, because you will be erasing the USB key, and you don't want to erase your hard drive by mistake!
Commands to try:
Code:
dmesg | grep -i scsi
Code:
cat /proc/partitions
Look at the sizes of the various drives you see here. Find your USB key, and do not get it confused with your hard drive! For the rest of this example, I'm going to be using /dev/sdz, a fictional drive letter that nobody has, just to prevent bad mistakes from typing in commands blindly.
* Erase the entire USB key.
Code:
dd if=/dev/zero of=/dev/sdz
Did you use the right drive letter? Did you? If not, you'll be crying, right about now....
This command will take a while to finish. By writing to every block on the USB key, we are also testing it for bad blocks.
You should get the "no space left on device" error message when it finishes erasing and reaches the end of the drive. Any other error messages might mean bad blocks: if you notice any, your key might be worn out and you'll need to buy another one (cheap keys are notorious for wearing out very quickly).
* Make a quick patch to the mkdiskimage script.
We need it to write partition type 0C (FAT32 LBA). Unfortunately, "out of the box" it only writes partition type 0B (FAT32 CHS). We want to make sure Windows always uses LBA and not CHS, for increased reliability, just in case we ever use the USB key with Windows. So, an easy one-line change.
Use your favorite editor and edit /usr/bin/mkdiskimage.
Code:
vi /usr/bin/mkdiskimage
Go to line 237.
Change 0x0b to 0x0c then save the file and exit.
* Run mkdiskimage, to automatically partition and format your USB key.
Code:
mkdiskimage -F -4 /dev/sdz 0 64 32
This lays down a new MBR and partition table on the drive, and partitions and formats the entire drive as one big FAT32 LBA partition. I prefer FAT32 because it is a more efficient use of space than FAT16, and have noticed no difference in the ability of various systems to boot FAT32 as opposed to FAT16.
The mkdiskimage script is USB-ZIP compliant, which may help it boot on more systems than USB-HDD. It's nice that Knoppix now includes this script by default. Here's the webpage for mkdiskimage: http://syslinux.zytor.com/usbkey.php
KDE may throw a stupid popup window in your face, once it recognizes your new partition. If this happens, close the window.
* Run the SYSLINUX installer on your new partition.
Code:
syslinux -s /dev/sdz4
This installs the SYSLINUX bootloader onto the newly-created partition, and includes a special file, ldlinux.sys. The -s option is for safety and additional compatibility. Notice the partition is the fourth partition on the drive, not the first. This is for USB-ZIP compliance.
* Mount your new partition.
Knoppix should have autodetected the new partition and set up a fstab entry for it. The /media/sdz4 directory should now correspond to the /dev/sdz4 partition.
You should notice one, and only one, file in this directory now: ldlinux.sys
If you don't see this, then something probably went wrong earlier. Go back and try again before continuing.
* Copy the contents of the Knoppix CD's boot directory, onto your USB key.
You should already be in the /media/sdz4 directory, from the cd command above.
Code:
cp -av /cdrom/boot/isolinux/* .
mv isolinux.cfg syslinux.cfg
rm -f isolinux.bin
Don't forget the dot on the end. It tells the cp command to copy everything into your current directory, which is what we want. Notice that there is a space between the asterisk and the dot!
Ignore any errors about "failed to preserve ownership". This is normal, because we're using the FAT filesystem, which does not support file ownership. This is not a problem for us.
What we're doing here is copying the Knoppix CD's /boot directory first. This increases reliability, by getting it as close to the beginning of the drive as possible. This should help on systems with buggy CHS handling of USB keys, which may become an issue as new USB keys get larger.
We are renaming Knoppix's isolinux.cfg file to syslinux.cfg, and then removing the unnecessary isolinux.bin file. ISOLINUX (used to boot the CD) and SYSLINUX (what we just installed to your USB key) are really two different variations of the same bootloader program. They accept the same config file format, so we don't need to change anything at all, just rename.
BTW, since ISOLINUX has isolinux.bin as its main program file, can you guess what is the equivalent file for SYSLINUX? If you guessed ldlinux.sys, the file you saw earlier, good job!
* Finish copying the rest of the Knoppix CD.
Again, you should still be in the /media/sdz4 directory. Again, don't forget the dot on the end of this command.
Code:
cp -av /cdrom/* .
rm -rf ./boot
This should take a while. We are filling up the USB key with the contents of the Knoppix CD.
We already copied Knoppix's /boot directory earlier, in the previous step. We don't need two copies of it just wasting space, so we remove the extra copy.
* You are now ready to boot!
Cleanly unmount the USB key.
Code:
sync
cd /
umount /media/sdz4
Shut down Knoppix, and remove the CD when it tells you to.
* Reset your computer and fiddle with the BIOS until it sees the USB key.
After unmounting above, the USB key can be removed. Some BIOS's require a removal and re-insertion before they will recognize it.
Other things to try, if you're having trouble getting the BIOS to see your USB key and let you boot from it:
Try a different USB port. Some BIOS's only search a few ports, not all of them.
Hit a special key to bring up a boot menu. Some BIOS's can only boot from USB when manually selected.
Go into your BIOS's setup menu, and walk through the boot settings. Look under all menus, especially "hard drives" and "removable devices" and other things like that. Some BIOS's will not search for newly attached devices until you manually go through the menus again.
Turn your computer completely off and on again. Some BIOS's require you to physically turn the computer off and on again, before they will see newly attached drives.
If all else fails, try a different PC. It's still fairly rare these days to find a computer that has a good ability to boot from USB devices, and it's not something that motherboard makers advertise, so it takes a bit of luck to find a computer that can do this.
* Boot into Knoppix from your USB key.
If it works, that's great. Notice how much faster it is. There's zero seek time on a USB key, so even though it isn't very fast, it feels a lot faster than the CD! Programs are surprisingly quick to load.
Find the drive letter for your USB key again. It should not change, but it might have.
* Make a persistent home directory, if you want.
Knoppix assumes that the "CD-ROM" that it booted from is impossible to write to, but we have a USB key now, not a CD-ROM. So, we must fool Knoppix into letting you write to it.
Code:
mount -o remount,rw /cdrom
mount --bind /cdrom /media/sdz4
Now, we can run the Knoppix persistent home utility.
(It's under the penguin menu, Configure, Create Persistent.)
Choose your drive from the menu that appears, and follow the instructions.
The program should complete without errors. If the program suddenly disappears midway through, check the kernel logs with "dmesg" again. If you see pagefuls of SCSI errors and such, beware, you might have a worn-out USB key!
* Modify the Knoppix boot menu.
This is an optional step, for customization. We want Knoppix to autofind the persistent home directory, and fix a few other things.
You might have to repeat the above mounting steps, as the Knoppix persistent tool might randomly unmount the directory sometimes.
Code:
vi /media/sdz4/syslinux.cfg
On line 3, the default timeout is 300. Lower this, to around 50 or so (5 seconds, since this counter is in tenths of seconds).
It's nice to have it boot faster, without waiting for you to hit Enter, so you can put in the USB key and walk away, coming back in a few minutes to a fully booted system.
On line 2, add a few more options to the end of the line.
noswap noeject noprompt dma home=scan
Here's a little explanation of what each option does.
noswap = Security fix: assuming you're going to be using the USB key on a bunch of different computers you don't own, you don't want to be swapping your memory onto their hard drives.
noeject = You can't physically eject a USB key.
noprompt = Gets rid of the "remove CD and close drive door" prompt when shutting down, as this prompt is rather misleading when it's really a USB key instead.
dma = Gets you a significant speed increase when dealing with many IDE drives, a good thing to have.
home=scan = This will cause Knoppix to pick up your persistent home directory automatically the next time you boot up, asking you for the password as needed. You will get an extra menu during bootup, asking you if you want to mount your home directory or not.
Save the file and quit the editor.
Now, you should be all set. Reboot again, to make sure it all works.
Enjoy your Knoppix-on-a-keychain!
Josh
Re: Got Knoppix 5.0.1 successfully booting from USB key
What a great write-up. I hope that you will consider putting a copy in the wiki where it will be easy for people to find.
Quote:
Originally Posted by Krellan2
...The mkdiskimage script is USB-ZIP compliant, which may help it boot on more systems than USB-HDD. ...
I'm particularly interested in this. My HP notebook has an option in the BIOS to boot from USB, but I have not yet managed to get it to boot a usb flash drive. My latest attempts were with the configuration that DSL writes to flash. Everything looked good, but it just would not boot (nor would it boot on an IBM laptop that I had a chance to try it on). I'm wondering if this is the issue. Can you explain how we can determine if a flash drive has been configured USB-ZIP or USB-HDD? Are there any trade-off we should know about? Unfortunatey, at this time my largest flash drive is 512 meg, too small for Knoppix. I would gladly buy a larger one if I thought that my notebook would boot it, but my bad experiences so far have discouraged me from buying a larger flash device; I have no use for more flash devices other that putting together a bootable Linux on flash (doesn't even have to be Knoppix, DSL or Puppy would be fine if I could get them to boot.) Can you suggest any test I can do with a smaller flash device (64, 256 or 512 meg) to confirm that my notebook will indeed boot a flash device?
Re: Got Knoppix 5.0.1 successfully booting from USB key
Quote:
Originally Posted by Harry Kuhman
What a great write-up. I hope that you will consider putting a copy in the wiki where it will be easy for people to find.
Thanks. I am working on debugging one problem on a certain machine, but after that, I'll attempt making a wiki page.
Quote:
I'm particularly interested in this. My HP notebook has an option in the BIOS to boot from USB, but I have not yet managed to get it to boot a usb flash drive. My latest attempts were with the configuration that DSL writes to flash. Everything looked good, but it just would not boot (nor would it boot on an IBM laptop that I had a chance to try it on). I'm wondering if this is the issue. Can you explain how we can determine if a flash drive has been configured USB-ZIP or USB-HDD? Are there any trade-off we should know about?
USB-ZIP and USB-HDD are both attempts to solve a problem: the BIOS expects all "disk" devices to have a traditional cylinder/head/sector count (CHS), but USB key s don't have this. Like most modern drives, they're just a total count of sectors (LBA). There's no need for the old cylinder/head/sector nonsense, but try telling that to the blunderheads who seem to be programming most BIOS's these days!
USB-ZIP attempts to simulate the layout of a ZIP drive: 64 heads, 32 sectors, and a variable number of cylinders depending on the size of the drive. In addition, ZIP drives use partition four (for whatever demented reason Iomega chose in the past). USB-ZIP was basically a hack to let a BIOS that was capable of booting from a ZIP drive, boot also from a USB key, with minimal reprogramming effort. Such is the state of the BIOS industry these days, I'm sad to say.
USB-HDD simply relaxes these restrictions. USB-HDD is supported by fewer BIOS's than USB-ZIP, however, so it's a tradeoff for compatibility. USB-ZIP will let your key boot up in more computers, so for now, it's the one to use.
You can change between USB-ZIP and USB-HDD by rewriting your partition table on the disk, and then reformatting.
Quote:
Unfortunatey, at this time my largest flash drive is 512 meg, too small for Knoppix. I would gladly buy a larger one if I thought that my notebook would boot it, but my bad experiences so far have discouraged me from buying a larger flash device; I have no use for more flash devices other that putting together a bootable Linux on flash (doesn't even have to be Knoppix, DSL or Puppy would be fine if I could get them to boot.) Can you suggest any test I can do with a smaller flash device (64, 256 or 512 meg) to confirm that my notebook will indeed boot a flash device?
I'm not sure. The main reason I bought a 1GB USB key was to put a complete bootable "CD" on it :)
Maybe you can try it with a remastered Knoppix that cuts down on the optional software (such as DSL). I haven't tried this myself.
Re: Got Knoppix 5.0.1 successfully booting from USB key
Quote:
Originally Posted by Krellan2
....You can change between USB-ZIP and USB-HDD by rewriting your partition table on the disk, and then reformatting.
....Maybe you can try it with a remastered Knoppix that cuts down on the optional software (such as DSL). I haven't tried this myself.
Most of what you wrote should be able to be cut and pasted into a wiki article pretty cleanly although code blocks and the like will take different formatting. But in the end it will be an easy thing for people to find; old forum posts tend to sink in the listings and are seldom see if they are not on the first page.
Thanks for the additional information. Let me ask my question a different way though. What in the partition table is it that flags USB-ZIP or USB-HDD? Lets assume I can byte edit the table, what bits or bytes am I looking for to tell me which I have?
DSL was one of the smaller bootable systems that didn't work for me (along with a few others, but the others were more convoluted to make and I could have done something wrong). Could I just hex edit the partition table to change from USB-HDD to USB-ZIP, or are the actual partitions different as well?
Give me low lever details, I can take it.
Re: Got Knoppix 5.0.1 successfully booting from USB key
Quote:
Originally Posted by Harry Kuhman
Thanks for the additional information. Let me ask my question a different way though. What in the partition table is it that flags USB-ZIP or USB-HDD? Lets assume I can byte edit the table, what bits or bytes am I looking for to tell me which I have?
DSL was one of the smaller bootable systems that didn't work for me (along with a few others, but the others were more convoluted to make and I could have done something wrong). Could I just hex edit the partition table to change from USB-HDD to USB-ZIP, or are the actual partitions different as well?
Give me low lever details, I can take it.
In the partition table, it's the CHS information. Ending CHS must be a size of */64/32. This is the biggie, as it seems the BIOS gets its CHS sizing information from what's read from the partition table! Starting CHS should probably be the standard 0/1/1, with starting LBA to match. Ending LBA should be truncated to match the ending CHS, so unfortunately, you end up losing a few KB from your USB key. But, it's worth it, if doing so lets it boot!
Your data partition must also be partition 4, and marked active. I haven't found a difference in filesystem type, as the BIOS should only care about this silly CHS information, and leave filesystems up to the OS.
Here's my partition table, as seen by "fdisk":
Code:
Disk /dev/sda: 64 heads, 32 sectors, 977 cylinders
Nr AF Hd Sec Cyl Hd Sec Cyl Start Size ID
1 00 0 0 0 0 0 0 0 0 00
2 00 0 0 0 0 0 0 0 0 00
3 00 0 0 0 0 0 0 0 0 00
4 80 1 1 0 63 32 976 32 2000864 0c
The hex dump (notice partitions 1, 2, 3 are all blank):
Code:
00000130 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
000001e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 80 01
000001f0 01 00 0c 3f e0 d0 20 00 00 00 e0 87 1e 00 55 aa
Notice I lose a little capacity from what my key really can hold:
Code:
SCSI device sda: 2001888 512-byte hdwr sectors (1025 MB)
Good luck! There's lots more to read online if you Google: "USB-ZIP" "USB-HDD"
(do not forget the quotation marks)
Josh
