Re: klibc - another libc?

["H. Peter Anvin" <hpa@zytor.com>]

Followup to:  <44869397.4000907@tls.msk.ru>
By author:    Michael Tokarev <mjt@tls.msk.ru>
In newsgroup: linux.dev.kernel
>
> After several mentions of klibc recently, I want to ask a question.
> 
> I understand all the kernel-mode cleanups -- moving initialization
> from kernel to user space is a very good thing.
> 
> But the question really is: why yet another libc?  We already have
> dietlibc, uclibc, glibc, now klibc...  With modern kernel, initramfs
> will very probably contain quite some programs linked with glibc
> (modprobe/insmod, mdadm/lvm, etc; I highly suggest putting some
> minimal text editor like nvi there too, for rescue purposes) --
> so why not have an option to use whatever libc is available on
> the host platform?
> 

You have that option just fine; if you build your own initramfs you
can do whatever you want.

> In the other words, kinit/ipconfig/nfsmount/etc stuff is ok,
> no questions.  But the libc itself -- what for?

To be able to *require* it, which means it can't significantly bloat
the total size of the kernel image.  klibc binaries are *extremely*
small.  Static kinit is only a few tens of kilobytes, a lot of which
is zlib.

> And another related question: why not dietlibc which is already
> here, for quite long time?

- Bigger by an order of magnitude
- License issues
- Platform support
- Speed of portability (klibc is fully portable to a new platform in an afternoon)
- Additional issues which you can find if look through the archives of this list

	-hpa