Re: my thoughts about grub 2

[Lennart Sorensen]

On Thu, Aug 19, 2010 at 04:47:06AM +0930, Brendan Trotter wrote:
> You missed my point - it doesn't work for Unix clones either. You
> could even have 2 copies of the exact same OS (something like Ubuntu)
> installed on the same computer (in different partitions), and it fails
> because both copies of the OS can't share the same "/etc". Any changes
> to "/etc" done by one copy won't be seen by the other copy.
> 
> A few sayings come to mind:
> - "Write programs that do one thing and do it well" (
> http://en.wikipedia.org/wiki/Unix_philosophy )
> - "jack of all trades" (
> http://en.wikipedia.org/wiki/Jack_of_all_trades,_master_of_none )
> 
> A boot manager can be very simple to install and very simple to
> configure. You should probably take a look at a few (I created a list
> including URLs earlier). A few of them even claimed to have "single
> click configuration" because they automatically detect installed OSs.

Then install a boot manager, and install grub2 for each unix clone you
want to boot seperately, and let the boot manager pick which grub2 install
to boot, and then let each unix clone manage their own grub2 config for
their kernels to boot.  grub is very much a boot loader.  It has some
support for booting other partitions, but the primary thing is to be a
boot loader.

> A pure boot loader (something without "boot manager" features, that is
> designed specifically for one OS only) typically needs a single
> command to install and doesn't need any configuration.

It needs config for which kernels or other things to boot.  Even ntldr
has a boot config file on windows.  The only ones that don't need config
are those that have no options (like the DOS boot loader).

> SYSLINUX is a collection of pure boot loaders. ELILO is a pure boot
> loader too. In the old days so was loadlin. If I remember correctly,
> early versions of Linux also had a boot loader built directly into the
> kernel (but I think that was only for booting from floppies). GRUB,
> LILO, SILO and PALO are a mixture. I can't think of any other Linux
> loaders.

isolinux certainly has a config file and supports lists of kernels and
options, so no syslinux is far from pure.  loadlin is, given it's config
was whatever arguments you passed it.  Not sure about elilo, although I
suspect it has a config somewhere to tell it which kernels to load again.
The kernel's floppy boot (which is long gone) could be considered a pure
boot loader.  Almost all are at least configurable.  Many are also able
to chainload other partitions or drives.  Few are pure boot loading on
any OS.

-- 
Len Sorensen