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TO ULF SAMUELSSON: Why "sigh" at uCLinux?

"I see as many ARM9 users as ARM7 users today and neither the CM3 or the uC3k will meet the performance of the ARM9 and neither will run Linux/WinCE. - uCLinux? ...sigh!"

I've only started reading about uCLinux over the last couple of days but I was wondering why you "sigh" at it.

I'm told that the Atmel AVR32UC3A/B (and their associated eval boards, the EVK1100/1) cannot run Linux because the processor doesn't have an MMU... hence something like the AVR32-AP7, at a minimum, is needed.

On the other hand, uCLinux is specifically designed to run on processors without MMUs. So, any reason why uCLinux cannot (or should not) run on the AVR32UCA/B?

Certainly uCLinux has its limitations but if it's the only flavor of Linux that will run on processors without an MMU, and the lack of MMU is the reason why the UC3x can't run Linux, then I would think that a uCLinux port for the UC3x would be welcomed by low-end processor developers... would it not?

Reply to
C. J. Clegg
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Is there a specific reason, why you want to run something Unix look-alike services on low resource platforms ?

While this makes sense when trying to port some existing Unix/Linux application to such platform, but for a completely new application, what is the point ?

When designing completely new applications in a shared address space environment, much simpler and lower overhead tasking can be used.

Paul

Reply to
Paul Keinanen

Good morning, Paul.

As a training exercise, mostly. I don't know very much that's worth knowing about embedded Linux, and virtually nothing at all about bringing Linux up on a new platform, and I've always been best at learning by doing and not by reading some book or attending a class.

That said, I have a friend who is a customer support engineer at the local Atmel office, and he says they do get inquiries and requests for Linux on the AVR32UC3x.... just not enough to justify the porting effort.

Reply to
C. J. Clegg

With Linux 2.6 looks like uCLinux is integrated in the main Linux distribution and (nearly) all API calls are compatible with standard Linux:

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Looks like the AVR32UC has max 512KB flash and 64KB RAM:

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This means uCLinux can't run on it without external memory, because it needs 1MB ROM and 200KB RAM:

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With external memory it is possible. One SDRAM chip and one serial flash chip should work.

--
Frank Buss, fb@frank-buss.de
http://www.frank-buss.de, http://www.it4-systems.de
Reply to
Frank Buss

"C. J. Clegg" skrev i meddelandet news: snipped-for-privacy@4ax.com...

uCLinux could run on any decent processor without an MMU.

Many applications which runs under Linux will not run under uCLinux, so they have to be rewritten. The memory handling sucks, so you probably need more memory with a uCLinux than you need with a Linux. The current 2.6 kernel can easily be > 1,6 MB (compressed) so you do not fit into the flash anyway.

See:

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Show me a project which is more cost efficient using uCLinux than Linux? Even if you pay a tad bit more for such a CPU, you also have to calculate the cost of maintenance to continously port new versions of S/W from Linux to uCLinux. Also the cost of delay of introduction due to the choice of uCLinux.

--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB
Reply to
Ulf Samuelsson

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