Memdisk Error When Booting iso

  • I am having trouble trying to add system tools to my fog installation. I have edited the advanced menu configuration and added the iso files to the menu and it attempts to boot from the iso. It seems to fail when loading the iso to memdisk.

    I get two errors. The first is MEMDISK: Image has fractional end cylinder and the second is MEMDISK: Bootstrap too large to load.

    The iso I am trying to load is WindowsNT Offline Password and Registry Editor which is 4.7 MB. I have other tools I want to add as well but am just trying to get this one working first. My advanced menu config is below you can ignore the entries other than the one for password editor. I have verified that i am able to get a download link in a browser when using the URL in menu config.

    item --gap – ---------------- iPXE boot menu ----------------
    item passwordedit Windows NT Offline Password and Registry Editor
    item dsl Damn Small Linux
    item bootrepair32 Boot Repair (32 Bit)
    item bootrepair64 Boot Repair (64 Bit)
    item return return to previous menu
    choose --default return --timeout 5000 target && goto ${target}

    chain memdisk iso raw ||
    goto MENU

    chain memdisk iso raw ||
    goto MENU

    chain ||
    goto MENU

    chain memdisk iso raw ||
    goto MENU

    chain${net0/mac} ||
    goto MENU


  • Ok, that would be useful. I am just trying to get a few diagnostic and system tools up and running from network boot so we won’t need to be able read/write, but that could definitely come in handy on another project. Thanks for all your help.

  • Developer

    well, for one, you could drop files like scripts into the network location that you’re booting into, to customize things. also, you could potentially set up a writable environment, whereas the ISO would be read only

  • OK. I see. Is there any advantage to that over just mounting the iso into memdisk? I can see how that would be faster than downloading and mounting the entire iso, but network speed isn’t really an issue in our situation. Mounting the iso seems to work with minimal issues at the moment.

  • Developer

    that isn’t likely to work. more likely you would need top take files out of the iso, and load them more like this
    kernel http://${fog-ip}/linux-distro/vmlinuz
    initrd http://${fog-ip}/linux-distro/initrd.img

  • Thanks guys.

    So to network boot Damn Small Linux, my menu entry would look like this? Or am I completely missing the point. I’m not trying to be dumb, I’m just really good at it. 🙂

    imgfetch DamnSmallLinux.iso[/CODE]

  • Developer

    I think what junkhacker is trying to say is that many versions of Linux come in a Netboot format that is intended for such purposes.

    I could be wrong too, I’m human, it happens 🙂

  • Developer

    what i mean is that “memdisk iso raw” copies the iso into ram, and then tries to pretend that the contents of the ram is a disk. linux has built in methods for booting from network and other non-disk locations

  • Yep. That was the problem. Tired eyes I guess. Looking right past an obvious error on my end. When I point to the file I want to boot rather than the directory it is in it works a little better. Thanks for your help.

    I’m not sure I understood exactly what you meant by a more native way to network boot Linux systems. Would I just leave out the line “chain memdisk iso raw ||”? I read the article you linked but am relatively new (1 week) to iPXE and FOG.

  • Developer

    do none of your iso’s have file name extensions?
    also, for linux based systems, there are more native ways to network boot them then chaining to “memdisk iso raw”

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