I've been using Ubuntu (because of ease of install / familiarity with Debian) as my test platform for rapid booting. Ubuntu is remarkably slow at booting -- It's made to work with just about any hardware. Can anyone recommend any distributions that are more geared towards the embedded rapid-boot? Essentially, I'd like to have a user-space program that's doing I/O via serial / usb to do data logging as quickly as possible, and everything else (display, mounting a mechanical hard drive) can wait. Essentially, steps 1-3 have to be as fast as possible.
1) LB + Filo -- Load Kernel from CF 2) Kernel init (I have this down to 0.9 seconds) 3) User space program that loads USB drivers and begins data logging 4) Everything else: network, display (X.org), hard drive mount etc
I need a distro that lets you do most of the usual startup stuff later.
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Here's a list of kernel options that I'm using -- anybody have any other "tricks" to speed this up?
root=/dev/hda1 console=ttyS0,115200 [I know this slows it down] console=tty0 [This might be a major time waster, also -- I suspect the kernel VGA init is slow] lpj=2136847 dhash_entries=16000 [I'm not sure if making the Dentry hash is slow, or if the VGA init routine just before it is the culprit] ide0=0x1f0,0x3f6,14 ide0=noprobe ide1=noprobe ide2=noprobe ide3=noprobe ide4=noprobe ide5=noprobe hda=65535,16,63 hdb=none hdc=noprobe [This is the CF -- don't need it after boot] hdd=none no_hlt
Also, If I do hda=noprobe, I guess the kernel won't mount it, so it fails. Seems like the kernel *must* probe the hd? I thought as long as it has the CHS, it didn't need to probe.