Node:Block list syntax, Previous:File name syntax, Up:Filesystem
A block list is used for specifying a file that doesn't appear in the
filesystem, like a chainloader. The syntax is
[offset]+length[,[offset]+length]....
Here is an example:
0+100,200+1,300+300
This represents that GRUB should read blocks 0 through 99, block 200, and blocks 300 through 599. If you omit an offset, then GRUB assumes the offset is zero.
Like the file name syntax (see File name syntax), if a blocklist
does not contain a device name, then GRUB uses GRUB's root
device. So (hd0,1)+1 is the same as +1 when the root
device is (hd0,1).