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  1. #1

    boot from ram ramdisk ? generic newb question

    Questions first incase no details necessary and u wana skip'm

    Are no partitions mounted? so its safe to modify/partition/test/etc the HDD with tools running from the ramdisk (which ofcourse normally warn to make sure the HDD is unmounted and not in use before proceeding)

    If answer to ?1 is, Yes (no partitions are actually in use) and safe to modify with utilites running from a ramdisk. Not mission critical but would be nice if anyone knows how to boot SystemRescueCD from ramdisk ? bellow is example of my normal grub legacy stanza i have used for it.
    Im using slitaz as the example but my question is for any distro when booting from ramdisk.

    I booted a slitaz cooking distro the same way ubuntu instructs to boot there ISO from HDD. gurb legacy slitaz stanza ex bellow.
    slitaz started up ok afk ,and shows no HDD partitions mounted ? however i have no clue if its Actually true or not. I am NOT a linux guru, i only know the basics and a few specific tasks for my needs.

    I know slitaz is designed to boot from ram, but its also not stated anywere on there site how to boot in this fashion, instead the usual CD/USB/or HDD etc install methods. So i dont know if this is normal behavior for slitaz as in doesn't mount partitions even if installed on HDD? or even if theres issues or not with the way i booted it and its a error/not displaying things correctly etc? It boots for me though basic operations iv used it for seem to work fine? im already aware its non-persistent in this way, which i actually prefer atm.

    title <> slitaz 20091124
    root (hd0,2)
    kernel /slitaz/vmlinuz- boot=slitaz root=/dev/ram ramdisk_size=65536 rw
    initrd /slitaz/rootfs.gz

    title <> systemrcd
    root (hd0,2)
    kernel /sysrcd/rescuecd subdir=sysrcd setkmap=us
    initrd /sysrcd/initram.igz

  2. #2
    Just Joined!
    Join Date
    Jan 2012
    Rowlett, TX
    QUESTION 1: depends. The job of the ramdisk of initrd (initial ram disk) is to ready the system so that it can mount the root filesystem. This includes, but is not limited to creating devices, inserting kernel modules, mounting the root file system, and switch_root + /sbin/init.

    It is important to note here that although this is the intended behavior, you could just load a kernel and an initrd with a custom /init or /sbin/init to halt the boot process at a shell within the initrd. I see you are trying to do something similar to that in question #2.

    Here is a good how-to on booting live iso's from grub2.
    h t t p://

  3. #3
    appreciate the input. good to know. dont usually post but often just hard to find specified info re: linux unless i dig thu some long drawn out tutorial or topic. like ur answer, short an to the point and understood ,but unfortunate for me lol i would need to do further learning of the specific tasks to acomplish that. I really only know basics

    I did however find the answer tho to my #2nd question. by adding a switch "docache" to the stanza as shown bellow. rescuecd then pre caches everything and boots directly from ram. Dont ask me why i didnt notice befor lol, im ona netbook an boot everything from HDD, but when i booted from usb i noticed a "cached to memory" option utilizing mentioned switch.

    title <> systemrcd
    root (hd0,2)
    kernel /sysrcd/rescuecd subdir=sysrcd docache setkmap=us
    initrd /sysrcd/initram.igz

  4. $spacer_open

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