[U-Boot] U-book and GPLv3? (fwd)

Jerry Van Baren
2009-06-19T00:46:27Z

Wolfgang Denk wrote:
> Hello,
>
> I was asked about relicensing U-Boot as GPLv3:
>
> ------- Forwarded Message
>
> Date: Thu, 18 Jun 2009 09:17:28 -0400
> From: Richard Stallman <rms@gnu.org>
> To: Wolfgang Denk <wd@denx.de>
> Subject: U-book and GPLv3?
>
> I really enjoy the name U-boot.

^_^

s/U-boot/U-Boot/ Wolfgang specifies that somewhere, but I cannot find
it now. :-P

> What are the advantages of U-boot over PMON?

This PMON?
<http://www.linux-mips.org/wiki/PMON>

OK, this looks a little fresher:
<http://olph.gdium.com/wiki/doku.php/system:pmon>
<http://dev.lemote.com/code/pmon>
<http://www.opsycon.se/PMON2000/Main>

Quotes below are from the <http://www.linux-mips.org/wiki/PMON> site
since it is more quotable. ;-)

1) PMON supports MIPS. Only MIPS? Before Y2K. After Y2K? Sorta.

U-Boot supports many processors and processor families. The current list
include the PowerPC, ARM family (many different manufacturers), AVR32,
Blackfin, Coldfire, Microblaze, MIPS, NIOS, NIOS2, SuperH, LEON, and
i386 (poorly, but /that/ ain't our fault).

2) "Everything about the PMON 2000 site is shaky at best. An updated
version promised in March of 2005 never materialized. The knowledgebase
is a joke and the documentation is a mixed bag."

U-Boot has a very active community. While the u-boot mail list isn't
quite the firehose that the linux mail list is, it is pretty easy to get
overwhelmed.

U-Boot has a passable knowledgebase <http://www.denx.de/wiki/DULG/Faq>
and a pretty good user's manual
<http://www.denx.de/wiki/view/DULG/UBoot>. Asking questions on the
email list generally results in quick and helpful responses, assuming
the question was a smart question
<http://catb.org/esr/faqs/smart-questions.html>.

3) "CVS access is supposed to be available but is not."

U-Boot "gits" it. OK, bad pun, but the point is, U-Boot has excellent
source control modeled after the linux development methods (two levels
with one BDFL and many custodians) and using the git distributed SCM tool.
<http://www.denx.de/wiki/U-Boot/Custodians>

4) It appears PMON is BSD-licensed. That is good for companies with
proprietary code, not so good for sharing and standing on the shoulders
of giants.

U-Boot is GPLv2 (sometimes "or later"). While that doesn't have as
sharp of teeth as GPLv3, unlike BSD it gives the community a legal lever
to pry code out of semi- and un-cooperative corporations.

---

U-Boot has a *lot* of functionality. It has a lot of helpful "board
bring up" commands, a (hacked) ash-ish command handler, ability to boot
an OS (linux or many others) over ethernet/TFTP or from a file system in
flash or from a USB disk or a hard disk or a SD card, or raw from flash
or over the serial link or...

This all fits inside 128K++, depending on the features and commands
compiled in. OK, mostly 256K, often bumping above that.

[snip]

Best regards,
gvb