Knoppix: CD-Based Linux

By Deane Barker on July 6, 2004

I’m writing this entry from a Linux machine…but I never installed Linux. I’ve booted my PC off a Knoppix disc, which is a bootable Linux CD. I’m in Linux now, but I just need to pop the CD and reboot, and I’m back to Windows.

You can get the CD image file at (I used Bit Torrent to get my version). Burn it to a CD, stick it in the drive, and reboot. You will boot into a really nice Linux distribution.

There are no users on the system — you’re automatically logged on as root (this was wrong — see the comments). If you’re worried about this, don’t be — remember that you booted from a CD. If you screw something up as root, just reboot and the system will be back to normal.

While Knoppix can read everything on your hard drive, it has no write access by default, so it’s not going to do anything to your existing stuff. You can allow it to write, but it’s not advisable with an NTFS drive. Knoppix creates a ramdisk to store all the stuff it needs while running. It accesses everything else off the CD, just like it would off the hard drive normally. When you run a new program, you can hear the CD spool up. Consequently, it’s slower than a normal Linux machine, but not by much.

It’s fully functional — it detected everything on my machine, including FireWire and USB devices. I just had to get the network card to broadcast a DHCP request and I was on the network. It recognized my Lexmark E210 printer just fine, and I’m listening to MP3s on XMMS as I write this. I had more trouble with my dedicated Linux install at work, and I spent days fiddling with that.

It comes with scads of software, like most Linux distributions — KDE, Open Office, The Gimp, Mozilla, Konquerer, etc. Since it forms a ramdisk when it boots, you can save files and work with them just as if it were a normal operating system. I saved the image above off a Web site, cropped it, and converted it to JPG in The Gimp. If I wanted to keep it beyond this session, I could always FTP it somewhere (remember that KDE is FTP-aware — you can map an FTP site to a local folder, so you’d never really know the difference).

I’m fairly well stunned by this. It’s really amazing. Sure, it can’t really store or persist anything locally from session to session (this can be overcome — see comments), but most of my apps are Web-based and my email is IMAP, so I’m actually pretty functional.

If you ever wanted to try Linux but you don’t want to make any changes to your current Windows set-up, Knoppix is exactly what you’re looking for.



  1. Anyone else have the awesome Lexmark E210? I want to find another one but can not. Lexmark (IBM) apparently figured out that $149 + $50 mail in rebate = laser printer too cheap to continue selling. The carts were $89 each but I found someone on eBay who sold me 2 toner bottles for $15 and I’m now going on 3,000+ from my original toner cart + 3/4 of one bottle of toner. Any way if anyone knows where to get an E210 please leave a comment.

    And so my comment isn’t completely off topic. I really like Knoppix even though I’m not into Linux anymore. But I’ve used Knoppix before on my desktop and laptop without any problems. It is really cool to see it work then play a few of the built in games.

  2. Some corrections: — You are not automatically logged in as root. You are logged in as a user called (I believe) knoppix. If you want to run as root, bring up a terminal and type ‘su’. Root has a randomly scrambled password, so if you want to, say, access a machine booted in KNOPPIX via ssh, you have to set a password for root.

    — You can easily set KNOPPIX up to persist data to the hard disk, a USB flash drive, whatever. Since it defaults to KDE, you can connect to web storage and more or less treat it like a local drive. You can even install KNOPPIX to the computer so it wil boot to KNOPPIX without the CD.

  3. I had great luck watching video too — Knoppix recognized all the of the Windows media formats just fine, and played them with wild abandon. The quality wasn’t quite the same. On a full-screen AVI, it was degraded enough where you could easily notice artifacts floating around on the screen. Perhaps I just needed a different or newer codec.

    When it came time to shut down and go back to Windows, I couldn’t get the CD tray open. Then I realized that you just restart the computer and Knoppix pops the tray and tells you to remove the CD and press enter to reboot to Windows.

  4. See also: Adios Linux. (

    Knoppix is Debian, Adios is Red Hat. In addition to running completely from CD, Adios also has a boot menu that offers to install the disk image to the hard drive. Think: Pristine Linux every time, HD boot speed.

    I think Adios is the one that lets you optionally write to NTFS, too, although that might have been one of the other CD-booting Linuxes I’ve tried. On Knoppix, writing to NTFS is dangerous and difficult to properly configure.

  5. I have been all over the internet for the last year and still have no luck writing to USB devices. I’ve tried different thumb drives and divverent hard drives, all to no avail.

    I tried mounting: mount -w /dev/sda1 /mnt/sda1 on my Knoppix and it won’t work. It was already in my fstab and mtab, so I tried editing them. Now I can’t umount without getting the busy error. “mtab” or “mtab~” ?I don’t get it. I thought that if knoppix was smart enough to scan my USB at startup, add everything to the fstab and automount each device, it would at least be able to write.

    I understand that different file systems need different options, but I don’t particularly care which Fs I use, as long as I can mount it in Win2K, WinXP and Linux, and maintain rw permissions under all three.

    any suggestions?

    I’m at my wit’s end… if you can help.


  6. Someone figured it out. FC3, FC4, Sarge, Knoppix 4 have all successfully written to my USB devices. It was too little, too late, because I no longer have to accomplish that important task I was supposed to have completed months ago. By the way, Who taught me how to spell “different” with two “v”s?

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