I've built a couple of scripts to build a tiny RTLinux system from
a full system for the flash disk. I can put it on the net if anyone
is interested. I've got another to prepair the flash disk and
install everything.
I've got a desktop system with two IDE interfaces that I use to plug
both the IDE and flash drive. I had no success in getting the IDE
and FLASH drive to cooperate as master and slave. Putting them on
separate controllers worked. This wasn't a problem since the Pentium
motherboard had two IDE controllers built-in.
I also wrestled with lilo. Little beast wouldn't install on anything
but hda. So here's what I ended up doing:
- put IDE drive on hda
- install Linux, then patch to RTLinux
- install application software, Java
- move IDE drive to hdc (second controller)
- put the FLASH disk on hda
- use the install boot disk and instruct it to use hdc as root
(mount root=/dev/hdc)
The mini-build scripts then mount the flash disk, prepare it,
install a compressed root file system, and run lilo. The system
is configured to run from ram disk with the flash remounted so
it can be used to store persistant information.
If the RTLinux community is interested in having this as a FAQ,
then I would be glad to prepare a more detailed guide to doing
this, with the scripts that I used, and the various config files
for lilo, etc.
Also, I'm not certain that this would warrent a FAQ, but I could
write a little blerb with code fragments on getting Java to
read properly from a FIFO. I've got it working, and I'm working
on what I hope will be a much faster way.
As for paring the JDK down, it can be done but the licence
seems to prevent one from pulling parts from it. It can be
made smaller if things like the AWT isn't required. Not that
I've done this of course, but that's what I've heard :-)
I'm currently using a Sandisk 40Mb IDE flash drive. It's
much too large for this project and I'm working on a smaller
device.
Advantech makes an IDE flashdisk about half the size of a
credit card. It has an IDE socket on it. It just plugs
right onto the IDE header on the SBC. It's perfect for
what I want. I've got the 8Mb version and have RTLinux booting
from it.
To enable it to connect directly onto the motherboard's IDE header,
the connector is the mirror image of a regular IDE cable, so I
built a small adaptor so I could plug it onto a regular IDE
cable and install RTLinux onto it.
Advantech is supposed to have at 16Mb version now. The RTLinux
system, Java, and all the libs that I need to run it fit into just under
20Mb, so I'm about to look for things to throw overboard to get
it down to 16Mb.
When the SBC has the small Advantech IDE flash disk installed,
you wouldn't even notice that it's there!
Regards,
Jim.
At 03:32 AM 11/18/98 +0200, Nikolay Ognyanov wrote:
>Hi James,
>
>Could you please tell us a bit more about your project? The problem
>of putting RT Linux into FLASH has been raised several times on
>this list but as far as I can recall you are the first one to present a
>real case study. Could you tell more about this : what kind of FLASH
>device you use, did you have problems with making Linux boot from
>it etc.? Also did you try to reduce in some way Java footprint ? How
>big your instalation (including Java) is?
>
>BTW, does somebody know about Embedded Java more than can be
>found on JavaSoft site? Could it have something to do with RT Linux?
>
>Regards
>Nikolay Ognyanov
>
>
