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Diffstat (limited to 'Documentation/blockdev/ramdisk.txt')
| -rw-r--r-- | Documentation/blockdev/ramdisk.txt | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/Documentation/blockdev/ramdisk.txt b/Documentation/blockdev/ramdisk.txt index 6c820baa19a..fe2ef978d85 100644 --- a/Documentation/blockdev/ramdisk.txt +++ b/Documentation/blockdev/ramdisk.txt @@ -36,21 +36,30 @@ allowing one to squeeze more programs onto an average installation or rescue floppy disk. -2) Kernel Command Line Parameters +2) Parameters --------------------------------- +2a) Kernel Command Line Parameters + ramdisk_size=N ============== This parameter tells the RAM disk driver to set up RAM disks of N k size. The -default is 4096 (4 MB) (8192 (8 MB) on S390). +default is 4096 (4 MB). + +2b) Module parameters - ramdisk_blocksize=N - =================== + rd_nr + ===== + /dev/ramX devices created. -This parameter tells the RAM disk driver how many bytes to use per block. The -default is 1024 (BLOCK_SIZE). + max_part + ======== + Maximum partition number. + rd_size + ======= + See ramdisk_size. 3) Using "rdev -r" ------------------ @@ -64,9 +73,9 @@ the RAM disk dynamically grows as data is being written into it, a size field is not required. Bits 11 to 13 are not currently used and may as well be zero. These numbers are no magical secrets, as seen below: -./arch/i386/kernel/setup.c:#define RAMDISK_IMAGE_START_MASK 0x07FF -./arch/i386/kernel/setup.c:#define RAMDISK_PROMPT_FLAG 0x8000 -./arch/i386/kernel/setup.c:#define RAMDISK_LOAD_FLAG 0x4000 +./arch/x86/kernel/setup.c:#define RAMDISK_IMAGE_START_MASK 0x07FF +./arch/x86/kernel/setup.c:#define RAMDISK_PROMPT_FLAG 0x8000 +./arch/x86/kernel/setup.c:#define RAMDISK_LOAD_FLAG 0x4000 Consider a typical two floppy disk setup, where you will have the kernel on disk one, and have already put a RAM disk image onto disk #2. @@ -85,7 +94,7 @@ The command line equivalent is: "prompt_ramdisk=1" Putting that together gives 2^15 + 2^14 + 0 = 49152 for an rdev word. So to create disk one of the set, you would do: - /usr/src/linux# cat arch/i386/boot/zImage > /dev/fd0 + /usr/src/linux# cat arch/x86/boot/zImage > /dev/fd0 /usr/src/linux# rdev /dev/fd0 /dev/fd0 /usr/src/linux# rdev -r /dev/fd0 49152 |