[ECOS] available?

Bart Veer bartv@redhat.com
Wed Apr 26 07:41:00 GMT 2000

>>>>> "Paul" == Paul Kinzelman <PaulK@isdcorp.com> writes:

    Paul> Still trying to get my arms around what's out there
    Paul> (X-files? :-).
    Paul> Does eCos have any support available for:
    Paul>  USB

Not that I am aware of. Looking at http://www.linux-usb.org/ , USB
support for Linux is still under heavy development and Linux has more
active developers than eCos.

Of course there is a more basic problem with USB support. In theory
you can plug any USB-compatible device into the bus, but you will need
driver code for each device. Right now eCos is statically linked, with
no support for dynamically adding code to the system. This is not an
oversight, eCos is designed for specific types of applications where
static linking is appropriate. Hence you would have to decide in
advance what USB devices can be plugged into the bus, and incorporate
appropriate device drivers into the application image.

If it is necessary to extend the system post-installation, in theory
there are ways around this. Some sort of dynamic code loading
mechanism could be added to the system, given sufficient effort. Or
you could use some sort of interpreter, possibly bytecodes, possibly
some sort of scripting language. All of these would involve
non-trivial amounts of work.

    Paul>  PCMCIA

The same applies as for USB: what cards do you expect people to plug

    Paul>  micro-browser

I know of at least one company porting such a browser to eCos, but
AFAIK they have not made any public announcements to that effect so I
cannot supply any more details. I am not aware of any open source
browsers that have been ported to eCos.

    Paul>  soft-modems

To quote from http://www.linmodems.org/

  "All winmodems are implemented via a chipset that a modem
  manufacturer solders onto a board. For better or worse, they're all
  incompatible with each other, just like Ethernet chipsets. Worse
  (definitely for worse), some of them seem to have documentation
  which is not publicly available."

I suspect that about the only way to get winmodems working with eCos
would be to get appropriate source code from the modem manufacturer,
with a sensible license. You would have to contact the various
manufacturers yourself about this.

    Paul> I believe I saw earlier there is nothing available for
    Paul>  java

Not yet, but being worked on:

    Paul>  file systems

Not yet. The basic infrastructure for this is being worked on as part
of EL/IX development.

    Paul>  any subset of X

X is not appropriate for most embedded systems, it is just too big.
Also, a typical X installation involves at least two processes, the
server and the client, which does not map well on to eCos. There are
other graphics libraries, e.g. NanoGUI, which might be more
appropriate. An important issue here is the kind of display you are
targetting - TV, large LCD, small LCD, ... - since something suitable
for a small LCD might look rather poor on a larger display.

Based on this list of requirements (USB, PCMCIA, browser, Java, file
I/O), I have to wonder whether eCos is really the right system for
your application. As soon as you add a browser and Java to the
equation you are talking about quite a few megabytes of memory in your
target system, so the size of the OS becomes less important. A
possible alternative would be embedded Linux.
http://www.redhat.com/products/edk/ would be a good place to start
investigating that option.

Bart Veer // eCos net maintainer

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