Syslinux - Aug 2008 - Some thoughts of Syslinux 4 architecture

So, I'm looking at what will be needed for the future of the Syslinux 
architecture.

One thing that keep coming up is that people want to combine things that 
  are normally associated with chain loading, specifically MEMDISK and 
disk swapping (from chain.c32) with other things like Linux kernels, and 
recursiveness.

Stefan's ELF loading support is obviously crucial to be able to keep 
data structures in memory as it provides continuity of data structures 
across modules.

In particular, I'm thinking of an architecture which would call into 
various modules, with MEMDISK being a module, and accumulate changes 
onto a shuffle list as it goes along, with the final invocation of 
shuffle_and_boot making this active.

There are, unfortunately, a number of potential hiccups with this. 
First of all we have the distinction of real-mode versus protected-mode 
invoked modules (which could be dealt with by a transition stub), things 
that we don't know a priori where they want to end up (things that need 
to be stuffed at end of DOS memory, especially, since we don't know that 
until cleanup time) and so on.

Anyway, thinking about it now...

	-hpa

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H. Peter Anvin wrote:
> So, I'm looking at what will be needed for the future of the Syslinux 
> architecture.
I haven't seen anywhere what your goals for syslinux are.  Are you
trying to take over all bootloading (ie also replace Grub and Lilo)?
The syslinux sweet spot currently seems to be booting anything except
hard disks (eg USB, network, CD) although extlinux blurs that.  And of
course "Linux" in the name implies other things are not supported or
not
a priority (Windows etc).

What I'd like to see out of a bootloader is less handholding and
babysitting.  We have billions of processor cycles per second and
gigabytes of memory, yet I have to tell bootloaders in mind numbing
detail what choices to offer me and comprehensive details about those
choices.  This is software - it should be figured out automatically!

For example if I booted syslinux on my machine, it should automatically
figure out I have an ubuntu installation with two kernels (and which is
more recent), a cdrom, a network card, a windows xp installation on a
second drive and a bazillion USB ports that may have something
interesting plugged in.  The configuration files should most of the time
be unnecessary, or if present augment and override select bits of what
was autodiscovered.  My pxelinux.cfg/default file is almost 8kb of very
repetitive config settings (various 32 bit and 64 bit ubuntu livecd as
well as some stuff from the sysrescue cd).  You can pick random
conventions - eg if you arrange some files in certain ways on a CD, hard
drive or tftp server then they appear automatically in the boot config.
 (Control freaks can then override with a config file if they want
things done differently).

The goal should be that people don't need config files.  For the few who
do, they are so self evident that no documentation is needed.  And then
that things "just work" so that noone ever needs to post to the list.
Zero list traffic is success :-)

On a completely separate topic, I would love memdisk for iso images.
LiveCDs are very popular but they are a royal pain to network boot
usually requiring extracting them, finding kernels etc, trying to
finagle an nfs root into the cmdline.  Being able to just point at an
iso image over the network and have it boot would be great.  I
understand it could take up up to 800MB of memory.  The minimum I have
in any machine is 2GB so it wouldn't matter.

Roger
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