[ELDK] What's the main difference between official Linux and DENX Linux ?

[Detlev Zundel]

Hello Gao Ya'nan,

as a general guideline, we want to stay as close to the upstream Linux
kernel as possible, yet still decouple our customers from the upstream
time schedule.  This effectively allows the customers to develop their
applications concurrently with the kernel changes going into mainline.

So in effect the DENX linux tree can be seen as a "staging" tree for our
custom specific additions.  In the past this for example allowed
customers with MPC5200 CPUs to participate in kernel development while
the transfer from arch=ppc to arch=powerpc when the 5200 support in
mainline needed time to regain the level of support that it had before.

The reasoning here is that up to today we always saw that back-ports
into old Linux trees or board support packages for a single specific
kernel version turned out to be a waste of effort, time and thus money.
Thus we we always suggest working with a mainline linux kernel which
also allows for a relatively smooth upgrade path during the long product
cycle which is typical in embedded projects.

> I compared the whole source tree, but it was beyond my knowledge.

Well this is understandable and we're actually actively working on
reducing the differences.

> why should I use DENX Linux instead of official Linux ?

If the CPU you are developing for is supported in mainline, then we
suggest to use mainline.  When on the other hand you need additional
items not yet supported there, you may either contract us to develop
them and publish them for your perusal in our tree as stated above or
you may be lucky and someone else did just this, so that our tree has
(at some point in time) better support for your hardware.  

In the long run, it is always be a smooth process to use the mainline
tree once it has all the features you need.

Best wishes
  Detlev Zundel

-- 
Question    : If you were redesigning UNIX, what would you do differently?
Ken Thompson: I'd spell creat with an e.
--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de