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.
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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