[syslinux] Kernel command line truncation

Firstname Surname hardum at gmail.com
Fri Nov 9 00:58:36 PST 2007


Using
kernel is 2.4.30
win32 syslinux 3.52
Preparing floppy under Windows XP SP2

1) Preparing boot floppy

======= syslinux.cfg content ======================
PROMPT 0
DISPLAY warning.txt
DEFAULT kernel
APPEND root=/dev/ram0 rw initrd=ukmrd.gz ramdisk_size=5000
bdev=/dev/fd0 ip=192.168.422.25 ipm=255.255.255.0 ipreq=n
ipg=192.168.42.1 ipdns=192.168.42.2 mnet=pcnet32
durl=http://KP/ukminstall
=============================================
After boot command line is truncated
  mnet=pcnet32 durl=http://KP/ukminstall
variables are not passed to init

2)  Preparing boot floppy with the win32 syslinux 3.52
 and syslinux-3.52\com32\samples\linux.c32 module

======= syslinux.cfg content ======================
PROMPT 0
DISPLAY warning.txt
DEFAULT syslinux 3.52
APPEND kernel root=/dev/ram0 rw initrd=ukmrd.gz ramdisk_size=5000
bdev=/dev/fd0 ip=192.168.422.25 ipm=255.255.255.0 ipreq=n
ipg=192.168.42.1 ipdns=192.168.42.2 mnet=pcnet32
durl=http://KP/ukminstall
=============================================
After boot command line is also truncated
  mnet=pcnet32 durl=http://KP/ukminstall
variables are not passed to init

Kernel parameters line is truncated at the edge of about 140 bytes


According to syslinux documentation
Changes in 3.08:
	* Max command line changed to 1023 characters.  Note that the
	  kernel proper still can only handle 255 characters without
	  patching, and COM16 binaries can only handle 125 characters.

Does it mean that under win32 it is impossible to pass 255 symbols to
the 2.4.30 kernel using syslinux?




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