[9fans] new pc bootstraps on sources

[g***@plan9.bell-labs.com]

9boot(8) is the place to start. 9boot replaces 9pxeload but is more
persistent. 9load and 9loadusb should behave much as the old ones
did, though I hope that the new ones will run on more machines. One
can boot through any PCI ethernet interface for which we have a kernel
driver now.

We are using 9boot to boot virtually all of our machines, including
those running amd64 kernels.

Thanks to my very patient beta testers, David du Colombier, John
Floren and the lsub crew. Gorka contributed new CD booting code and I
swiped Russ Cox's old decompressing executable header.

[Richard Miller]

Post by g***@plan9.bell-labs.com
9load and 9loadusb should behave much as the old ones
did, though I hope that the new ones will run on more machines.

With either of these, I get
panic: RMCODE < 2070 bytes

It seems that the real-mode code is a bit large:

term% nm -ng /386/9loaddebug
80010000 T _start16r
80010000 T _KTZERO
...
80010816 T realmodeend