In my quest for directly attaching flash storage to a conventional PC via the BIOS-ROM socket available on NIC cards, I've got some flash chips on order, and dug through several unpacked boxes from my office move and finally found my 8 Meg Disk-On-Chip.
I've also been reading through the technical reference documents for the 3Com 3C905 series NIC's and the DEC 2114x based chips (tulip). Both of these chips will support flash parts, and look like they could be coerced into supporting a DOC part as well. I think I'll begin experimenting with the 3Com NIC's, since the only tulip based cards I have are the DFE-570 quad-port (no rom sockets), and the NetGear FA310's (un-populated ROM socket, and I don't have details on NetGear's ASIC version of the DEC ethernet core). The 3Coms will only support up to a 29C010 (128K x 8), but this should be big enough for configuration data (my CD systems are running with about 50K used on the config floppy). Of course, getting DOC support going would pretty much eliminate all size problems. Currently, it looks like the easiest thing to do would be to get run-time support working for either a single flash part or a DOC part...both will probably take about the same amount of effort. Hopefully, this can be done without having to customize the NIC driver (I haven't yet crawled through the NIC drivers to see if the lock the register I/O space of the cards), but even if it requires patching the 3c59x driver, it *can* be done. Getting a diskless system working this way could be a bit thorny...it would require a custom BIOS extention to be written and loaded into the DOC (I don't think there's any way we can squeeze a running LEAF system down to 128 KBytes, or even the 512K available on a 29C040 part), but there's no reason (other than lack of time) that booting from the DOC couldn't be made to work as well (assuming enough details of the DOC internals can be squeezed out of M-Systems...basically a routine for updating their BIOS image). This is kind of an interim project for me...something fun to play with while noodling about new packaging requirements in the back of my head. I'm hoping to get something running before the end of the year. A CD based system with no floppy would be kind of a cool thing, as would having a cheap & standard way to hook a DOC to a "mainstream" computer system (ie not one of the expensive embedded oriented systems). Booting off the DOC would be even cooler, but I don't know if I have time to start writing BIOS code in assembly :< Charles Steinkuehler http://lrp.steinkuehler.net http://c0wz.steinkuehler.net (lrp.c0wz.com mirror) _______________________________________________ Leaf-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/leaf-devel
