should we continue to focus on nuttx?

Gregory Nutt spudarnia at
Mon Apr 30 17:14:28 UTC 2012

Hi, all,

Of course, I am not impartial, but I do want to point out two things.  First, there appears to be some misconception that NuttX is big and heavyweight.  That is certainly not true.  Most implementations use only about 40Kb or so (depending on the features that you incorporate).  And you can get it as small as 12Kb; it will run on a z8 or an 8051 or an AVR with 4Kb of RAM.  That 40Kb footprint is for a complete environment that might include displays, USB, networking, filesystem, support etc.  Well, if you include everything it pushes about 50Kb.

So I have trouble understanding that the issue there.  And secondly, NuttX does have a rather complete graphics capability.  Probably the best in class:

1. A window system like a tiny X  that is scalable from a single thread solution to a full multiple NX server (see 

2. An extensive "widget" for adding buttons, textboxes, etc. to NuttX.  This has only been 
released to open source recently but is fairly matured because it has 
been integrated into commercial products 
( and

3. Finally, I am currently developing a tiny window manager that I am calling nxwm.  This was 
inspired by the Matchbox Window Manager concept:  That is, it is truly 
multiple window manager but only one window is display in time.  This 
simplification helps performance on LCD based products (in the same way 
that a tiled window manager helps) and also makes the best use of small displays.  It is awkward trying to manage multiple windows on a small display.

nxwm is oriented toward tiny screens with touch capability.  It supports a 
task bar and a start menu with the normal meanings.  I have only been 
working on this for about 3-4 days,and I don't expect to have this 
complete for another week or so.  But it is something else that you 
should be aware of if graphics support is important to you.

The code is growing here:

But I find that RTOSs tend to be religious topics.  People get strong opinions with very little information. So other than providing all of the information that I can and providing the best support that I can, I am not involved in this decision.


 From: Harald Welte <laforge at>
To: Denis 'GNUtoo' Carikli <GNUtoo at> 
Cc: baseband-devel at; Alan Carvalho de Assis <acassis at>; Gregory N <spudarnia at> 
Sent: Monday, April 30, 2012 10:02 AM
Subject: Re: should we continue to focus on nuttx?
Hi Denis,

there was no decision on OsmoDevCon, apart from some opinions.

I'm not aware of anyone actually having reviewed/evaluated rockbox at
this point.

The general point was that we apparently don't really _need_ a "full OS"
like NuttX, but there are other solutions like rockbox that may bring in
other useful parts like a UI for low-resolution dot-matrix displays.

I guess until somebody actually tries and experiments with an early port
of rockbox to the calypso, we won't know what is the best way to move
forward :/

And in general, everybody seems to be busy with lots of other things, so
I'm not sure if (and when) that might happen.


- Harald Welte <laforge at> 
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)
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