Specifications

The `ramdisk_start=' Argument
To allow a kernel image to reside on a floppy disk along with a compressed ramdisk image, the
`ramdisk_start=<offset>' command was added. The kernel can't be included into the compressed ramdisk
filesystem image, because it needs to be stored starting at block zero so that the BIOS can load the bootsector
and then the kernel can bootstrap itself to get going.
Note: If you are using an uncompressed ramdisk image, then the kernel can be a part of the filesystem image
that is being loaded into the ramdisk, and the floppy can be booted with LILO, or the two can be separate as is
done for the compressed images.
If you are using a two−disk boot/root setup (kernel on disk 1, ramdisk image on disk 2) then the ramdisk
would start at block zero, and an offset of zero would be used. Since this is the default value, you would not
need to actually use the command at all.
The `load_ramdisk=' Argument
This parameter tells the kernel whether it is to try to load a ramdisk image or not. Specifying
`load_ramdisk=1' will tell the kernel to load a floppy into the ramdisk. The default value is zero, meaning that
the kernel should not try to load a ramdisk.
Please see the file linux/Documentation/ramdisk.txt for a complete description of the new boot
time arguments, and how to use them. A description of how this parameter can be set and stored in the kernel
image via `rdev' is also described.
The `prompt_ramdisk=' Argument
This parameter tells the kernel whether or not to give you a prompt asking you to insert the floppy containing
the ramdisk image. In a single floppy configuration the ramdisk image is on the same floppy as the kernel that
just finished loading/booting and so a prompt is not needed. In this case one can use `prompt_ramdisk=0'. In a
two floppy configuration, you will need the chance to switch disks, and thus `prompt_ramdisk=1' can be used.
Since this is the default value, it doesn't really need to be specified. ( (Historical note: Sneaky people used to
use the `vga=ask' LILO option to temporarily pause the boot process and allow a chance to switch from boot
to root floppy.)
Please see the file linux/Documentation/ramdisk.txt for a complete description of the new boot
time arguments, and how to use them. A description of how this parameter can be set and stored in the kernel
image via `rdev' is also described.
The `ramdisk_size=' Argument
While it is true that the ramdisk grows dynamically as required, there is an upper bound on its size so that it
doesn't consume all available RAM and leave you in a mess. The default is 4096 (i.e. 4MB) which should be
large enough for most needs. You can override the default to a bigger or smaller size with this boot argument.
Please see the file linux/Documentation/ramdisk.txt for a complete description of the new boot
time arguments, and how to use them. A description of how this parameter can be set and stored in the kernel
image via `rdev' is also described.
The Linux BootPrompt−HowTo
The `ramdisk_start=' Argument 9