Downloading FAQ

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Tip: Use CD-RWs instead of CD-Rs every time you can - save your budget and our environment!


Q: How do I get the CD/current beta?

A: Several possibilities:

Q: Can you download Knoppix in parts if you have a low bandwith (28.8 Kbps) such a pausing the download and continue it another day?

A: Yes, Bittorrent supports resume, and so does many ftp clients such as wget ( use wget -c ) or ncftp. You can use other download managers too.

Q: What are these strange MD5 files that accompany the ISO CD images?

A: The files with the .md5 extension contain checksums for the actual CD ISO images. A MD5 checksum is a way of fingerprinting files. Just like a real fingerprint identifies a single person, a MD5 checksum is unique and matches exactly one file. It is used to verify that the file downloaded matches the original all the way down to the smallest details. In the case of downloading a Knoppix ISO image, the MD5 checksum is used in order to verify that the file downloaded is perfect and not corrupt.

When you download both the ISO image for the CD, you also must download it's corresponding .md5 file. The .md5 file is a plain-text file and can be viewed in a text editor or web browser. You can verify that your download was perfect and that the ISO's contents are unchanged by typing "md5sum -c filename.md5" under Linux/Unix.

Further information about MD5 and programs for various OS's can be found at and The MD5 Protocol Documentation. Here is a small list of MD5 checksum calculators for Windows™ but note that the methods to verify the checksum & make sure you have a perfect ISO file vary between programs.

Q: What are the ASC files that accompany the CD ISO images and MD5 files?

A: The files with the .asc extension are PGP-signed messages that contain the md5sum used for verifying the ISO CD images. With this you can be sure the ISO image and accompanying MD5 file are genuine, because the .asc file containing the MD5 is signed with Klaus Knopper's PGP key. This could only be compromised if someone got hold of the secret key used to sign the message. To verify the file, you need to import PGP key ID 0xBA8F038D from your favorite keyserver, then in Linux you can type "gpg --verify KNOPPIX_Vxxxxxxxxxxxxxxxxx.iso.md5.asc". Then you must check that the MD5 checksum in the .asc file is the same that the MD5 checksum in the .md5 file.

If you want to verify the signed md5 file and the ISO file in one step, you can type:

gpg --decrypt  KNOPPIX_Vxxxxxxxxxxxx.iso.md5.asc | md5sum -c -

Q: I have downloaded the ISO file, now what ?

A: Several possibilities again:

  • Linux: you can use the command:
cdrecord -v speed=4 dev=0,3,0 filename
where dev=0,3,0 is your cdwriter
(Attention, use "cdrecord -scanbus" before cdrecord to be sure that dev=0,3,0 is you cd-writer. If you own SCSI hds, you could lose all data of one hd when you use cdrecord with a wrong dev=(controler,id,partiton) !)
  • Windows quick answer: You will need one 700M blank cd. Use a program such as Nero burning rom. You can get a free trial of Nero from their site. To burn with this program, skip the wizard and choose File>Burn Image. Select KNOPPIX_Vxxxxxxxxxxxxxxxxx.iso file,>Burn. (Notice, Nero 6 has a bug preventing it from burning large images, for a patch see: this forum discussion)
  • Windows long answer: Of course the answer depends on the individual program you are using to burn CDs, but all common CD-Writing programs should support the option of burning bootable ISO-Images, you probably just have to find the right menu option. At the address for Knoppix documentation and on some of the KNOPPIX-Mirrors in a directory with the same name, you may find some examples written as short step-by-step documentations from users who successfully completed the procedure. KNOPPIX_Vxxxxxxxxxxxxxxxxx.iso -files are ISO-Images, which uses "El Torito"-Specification (documented here).

In the ISO-Image there is not only user-data, but also information about the file structure of the CD itself. If you want to see the file structure, have a look at Isobuster.

To get the image-file on CD use RAW-Mode of your burning-software (have a look at Bild 1 WinOnCD German Edition).

  • Select the KNOPPIX_Vxxxxxxxxxxxxxxxxx.iso as filename of the image.
  • Select 2048 Bytes/Sector as the correct data format (see Bild 2 WinOnCD German Edition).

Burn your CD as a "Single Session CD" or select finalize. The Mode "Disk at once" or "Track at once" should be irrelevant for a data-CD (have a look at the Online-Help of your burning software). If the CD boots, but they are read errors, try "Disk at once".

Q: My computer won't boot from CD. What should I do?

A: Look in your computer's BIOS (on many computers you need to push the "delete" or F1 key during the POST) to see whether it is set to boot from CD. If this is already set, your computer may not be able to read the CD (some notebooks have problems with black-coated CD's, for example). Some computers will only use the new BIOS settings after a hard reset. Other resources are this page which explains the PC BIOS and this page explains the boot order.

A: If your computer doesn't support booting from CD, you can create a bootfloppy using the "rawrite" or better yet the mkfloppy.bat file program in the "KNOPPIX" directory on the CD.

A: Get the Smart Boot Manager, and install to floppy, this should let you boot from any bootable CD. . If you want to install from windows, download the sbminst.exe and run it from the Command Prompt like : sbminst.exe -d 0 to install to floppy drive.

Q: I downloaded KNOPPIX via WWW/FTP or got a downloaded version from a friend. My PC will boot off of it, but the bootup stalls after a bit or I only see the background picture, and nothing else happens. What's going on?

A: You possibly only got a partial download or the download was complete but corrupt. If this is the case, then the ISO image is defective and the CDR burn of Knoppix is also defective. This is because the data in the missing/changed parts cannot be accessed (sometimes one can even "hear" this because of the sound the CD-ROM drive makes due to repeated read attempts). It appears to work because the directory tree is written at the beginning of the CD and can be correctly read. However, reading the actual contents of the missing/changed parts is impossible, or in other words, accessing the contents fails. Some possible solutions can be found in the section "What are these strange MD5 files that accompany the ISO CD images?" and "How can I get the CD?".

Q: After I've used KNOPPIX, my "other" OS suddenly shows a blue screen with the message "File kernel.exe not found or defective" and "reinstall..." shortly after boot.

A: Simply take the KNOPPIX CD out of the CD-Rom drive and restart the computer.

Q: I see the partitions from my hard disk on the desktop and can access their contents when I click on them, but if I try to write to them I always get the error message "access denied". How can I write to my existing partitions?

A: The general philosophy of KNOPPIX is to allow as little write access as possible. For this reason, existing partitions are either not mounted or only mounted "read only". If you click with your right mouse button on an icon, the "read-only" attribute under item "device" can be un-checked. After this, the partition can be mounted "read-write" (for already mounted partitions, first click on "unmount"!). CAUTION: writing to NTFS partitions can lead to data loss, since Linux does not really support this file system! However, DOS and FAT32 file systems are safe for write access. Tip: In the shell the command "mount -o remount,rw /mnt/" can allow already-mounted file systems to be "made writeable".

Q: I have a fast access to a Knoppix-mirror. How can I burn with GNU/Linux this ISO file directly to CD-RW?

- mkfifo KNOPPIX.fifo # mkfifo create a fifo file
- screen ftp mirror ....# screen creates multiple shells in one terminal (handy!) ftp connect to your mirror...
get KNOPPIX-3.10-EN.iso KNOPPIX.fifo #command to copy inside your ftp-session
- C-a C-c # screen will make a new shell
- cdrecord dev=(your burner) speed=4 KNOPPIX.fifo # ftp starts to get data when cdrecord starts to read from fifo
wait; exit; rm KNOPPIX.fifo; exit

(Attention, use "cdrecord -scanbus" before cdrecord to find the correct device of your cd-writer. If you own SCSI hds, you could lose all data of one hd when you use cdrecord with a wrong dev=(controller,id,partiton) !)


This works well and is much simpler: wget -O - URL_OF_IMAGE | cdrecord -v speed=4 -eject -

Q: Must I burn Knoppix on CD-RW to be able to test it?

A: When you run another GNU/Linux system, you can copy the content of the Iso-file to your hd and boot it directly from hd. See Hd Based HowTo.

Q: How do I burn an image on to a CD using B's Recorder Gold from BHA?

A: Close the Wizard dialog if it pops up when you start the application. Drag the KNOPPIX-*.iso file to the lower RIGHT region of the app window. It is shaded in yellow and has the title "Track Type"(The icon with a musical note and a folder will be seen in the middle panel). Right click the left region where it says ")1 DATA -mode1 and from the popup menu choose properties. Choose "ISO compatible" and "create from standard bootable disk image" in the two selection boxes. Then press the record button (Upper left), pick your options, and Voila - one KNOPPIX bootable CD is yours.

Q:Why do 750 MB fit onto an audio CD but only 650 MB onto a data CD?

A: A sector of a CD consists of 2352 bytes. With an audio CD, these are used completely for audio information. With data CDs, an additional fault correction is inserted, and the usable capacity shrinks to 2048 bytes. A 74 minute CD consists of 74x60x75 = 333000 sectors. With 2048 bytes per sector, this gives a usable capacity of around 650.1 MB, with 2352 bytes per sector it gives around 746.6 MB. This therefore also produces a difference in data rates for reading/writing: 172 kbps with audio and 150 kbps for data.

Q: Why does my writer/software not accept to write to my 80 minute CD-R?

A:Some older writers or older versions of writer software cannot recognise the new playing lengths, because the groove is laid more narrowly. Check with your hardware and software manufacturer to see if these newer media are supported. In most cases, updating the writer software's current firmware (check out the web site of the software manufacturer) will solve these problems.

Q: What to do if I haven't got enough space in the CD to burn Knoppix on it?

A: You can overburn it ( ).