[LispM-Hackers] Target platforms for porting
Mon, 19 Mar 2001 23:04:32 -0500
"James A. Crippen" wrote:
> However, I *really* am looking forward to getting e3 to run on
> > bare iron (I have an old P5 166MHz 32MB box that I was using to develop
> > JOS, which would disklessly etherboot the JOS kernel/JVM on bare iron).
> Sounds good, except how are you going to etherboot? DHCP? BOOTP? You'll
> need some sort of simple loader program that understands the ethernet
> device. And that's not as easy on an x86 as it is on a Sun, say.
Etherboot is a package. It consists of (obviously) some real-mode
packet-driver-type software that you can burn as a bootable floppy. The
x86 box boots off the floppy and screams "Mommy!" over the ethernet
(BOOTP) and receives back some info and then TFTPs an "NBI" format
(NetBootable Image) block of bits consisting of a table of contents and
some random associated data segments. Using the host tools, you can
build the NBI file to include, say, the "microcode" (including some
software to get you from real to protected mode which I've already
written and debugged) and, say, a compressed-to-hell load band. You
have some control over where things get loaded when you build the table
of contents (although the entry point has got to be loaded under the
stupid 20 bit address limit). For JOS, I wrote a zip-file
implementation (non-compressed, unfortunately) which contained the Java
classfiles for the JVM to search when it needed to. It's pretty
convenient, and it beats the hell out of rebooting your single
development box over and over again. We could add compression and then
put the band (and any other files we'd need at boot time) in the
zipfile-format ramdisk. We can then reclaim the memory after it's
loaded (didn't get that far with JOS, but you can specify the location
w.r.t. the "end of physical memory," so I put the ramdisk there so it
would be easier to reclaim if necessary.
> > > Can anyone think of other platforms and which category to file them
> > > under? Any other comments?
> > (3) I think e3 would mesh wonderfully with resource-challenged hardware
> > (e.g., the Compaq iPaq (or however they're capitalizing it these days),
> > the Palm Pilot, etc.). However, It
> It what? :)
Agh. It might not have enough memory to be really useful (although I
understand they have quite a bit more than my PalmV).
==== John Morrison
==== MAK Technologies Inc.
==== 185 Alewife Brook Parkway, Cambridge, MA 02138
==== vox:617-876-8085 x115