[syslinux] MEMDISK: feature requests

Gert Hulselmans
Tue, 03 Aug 2010 22:04:33 -0000

I mentioned it some time ago. If you want to specify another BIOS drive
number for a CDROM drive you want to emulate with MEMDISK, you need to do
it this way:

memdisk iso harddisk=hd40 initrd=some.iso

It is not very logical. It would be better if the drive number could be
added to iso:

memdisk iso=cd40 initrd=some.iso

I am not sure which BIOS drive number should be allowed for that and which
prefix should be used, maybe without the prefix is even better:

memdisk iso=40 initrd=some.iso

Does the harddisk= command allow hexadecimal numbers?


Another feature, when booting ISO images, would it be possible to disply
which kind of eltorito emulation the image uses?
 - floppy emulation
 - hard disk emulation
 - no-emulation

For example display it on the "Disk is hd96, 2034.5 K, C/H/S 65535/255/15
(El Torito/El Torito), EDD on, rw" line.

MEMDISK 4.02 pre3-3-gc607c38  Copyright 2001-2010 H. Peter Anvin et al
e820: 0000000000000000 000000000009f000 1
e820: 000000000009f000 0000000000001000 2
e820: 00000000000e8000 0000000000018000 2
e820: 0000000000100000 0000000007ef0000 1
e820: 0000000007ff0000 0000000000010000 3
e820: 00000000fffbc000 0000000000004000 2
e820: 00000000fffc0000 0000000000040000 2
Ramdisk at 0x077fd000, length 0x007f2800
command line: pause iso
MEMDISK: Image seems to have fractional end cylinder
MEMDISK: Image appears to be truncated
Disk is hd96, 2034.5 K, C/H/S = 65535/255/15 (El Torito/El Torito), EDD
on, rw
Using safe INT 15h access to high memory
Code 1860, meminfo 168, cmdline 10, stack 512
Total size needed = 2550 bytes, allocating 3K
Old dos memory at 0x9f000 (map says 0x9f000), loading at 0x9e400
1588: 0xffff  15E801: 0x3c00 0x067f
INT 13 08: Failure, assuming this is the only drive
Drive probing gives drive shift limit: 0xe2
old: int13 = f000e3fe  int15 = f000f859  int1e = f000efde
new: int13 = 9e40000a  int15 = 9e4003fd  int1e = f000efde

Disk is hd96, 2034.5 K, C/H/S = 65535/255/15 (El Torito/El Torito), EDD
on, rw
Why is the parameter between the () displayed twice?
Hi Shao,

I mentioned it some time ago. If you want to specify another BIOS drive
number for a CDROM drive you want to emulate with MEMDISK, you need to do
it this way:

memdisk iso harddisk=hd40 initrd=some.iso

It is not very logical. It would be better if the drive number could be
added to iso:

memdisk iso=cd40 initrd=some.iso

I am not sure which BIOS drive number should be allowed for that and which
prefix should be used, maybe without the prefix is even better:

memdisk iso=40 initrd=some.iso

Does the harddisk= command allow hexadecimal numbers?


Another feature, when booting ISO images, would it be possible to disply
which kind of eltorito emulation the image uses?
 - floppy emulation
 - hard disk emulation
 - no-emulation

For example display it on the "Disk is hd96, 2034.5 K, C/H/S 65535/255/15
(El Torito/El Torito), EDD on, rw" line.

MEMDISK 4.02 pre3-3-gc607c38  Copyright 2001-2010 H. Peter Anvin et al
e820: 0000000000000000 000000000009f000 1
e820: 000000000009f000 0000000000001000 2
e820: 00000000000e8000 0000000000018000 2
e820: 0000000000100000 0000000007ef0000 1
e820: 0000000007ff0000 0000000000010000 3
e820: 00000000fffbc000 0000000000004000 2
e820: 00000000fffc0000 0000000000040000 2
Ramdisk at 0x077fd000, length 0x007f2800
command line: pause iso
MEMDISK: Image seems to have fractional end cylinder
MEMDISK: Image appears to be truncated
Disk is hd96, 2034.5 K, C/H/S = 65535/255/15 (El Torito/El Torito), EDD
on, rw
Using safe INT 15h access to high memory
Code 1860, meminfo 168, cmdline 10, stack 512
Total size needed = 2550 bytes, allocating 3K
Old dos memory at 0x9f000 (map says 0x9f000), loading at 0x9e400
1588: 0xffff  15E801: 0x3c00 0x067f
INT 13 08: Failure, assuming this is the only drive
Drive probing gives drive shift limit: 0xe2
old: int13 = f000e3fe  int15 = f000f859  int1e = f000efde
new: int13 = 9e40000a  int15 = 9e4003fd  int1e = f000efde


Why it the parameter  between the (), displayed twice?
  Disk is hd96, 2034.5 K, C/H/S = 65535/255/15 (El Torito/El Torito), EDD
on, rw


- Gert Hulselmans