Okay, a while ago I asked a stream of questions about my 7500 box, got
some answers, then fell silent, so here's how things are and what I
had to do to get them there:

The G3 daughtercard I have for this machine works perfectly - it's an
"XLR8 MachSpeed G3 w/MVP", 300 MHz with 1 MB level 2 cache. I haven't
tried overclocking it (possible as it assumes a 40 MHz bus and the
7500 has a 50 MHz one and, in fact, supported by XLR8 by way of
switches on the card itself), but I might play with that and see if
NetBSD remains stable. I do question whether NetBSD uses (or should
use) the level 2 cache - any way to find this out? Anyway, those of
you with aging PowerMacs with swappable daughtercards should
*definitely* pick up one of those G3 cards now that they're only a
couple hundred (US) dollars - a glance at top on my box compares
favorably with the Sun Ultra 10s (333 MHz machines) and even comes
close to the bigger of the two Enterprise 450s here at
cs.swarthmore.edu.

I managed to get a kernel compiled with BUFPAGES set to 1024, which
allows me to use all of the 240 MBs of RAM I have for this machine
with no problem. I don't have the slightest what was causing me
problems with the kernel booting before... could have been that the
kernel was not executable? Anyway, it works now following the
directions in the standard NetBSD FAQ to the letter.

I have one of my old mac68k drives mounted (the important one, /, as
opposed to the less relevant one, /usr) by using the MkLinux pdisk
utility on a mac, writing down the start sector and length of the
partitions, then connecting the drive to my macppc machine and
disklabeling the disk by hand. I know Bill's put support for this
stuff in -current, but I'm still running 1.4.1, so I did it the manual
way (worked without a hitch - thanks for that advice earlier this
year, Bill).

This all leaves me with some lingering questions:

1) Is NetBSD using the L2 cache on my G3 daughtercard? How would I
know?

2) Does /netbsd need to be executable? If so, why? (Is there even a
file system around when it's loaded into RAM? A bootstrapped one?)

3) Remember that /usr mount point drive I couldn't get to work? Here's
why (from dmesg):

obio0 at pci0 dev 16 function 0: addr 0xf3000000
esp0 at obio0 offset 0x10000 irq 12: NCR53C94, 25MHz, SCSI ID 7
scsibus2 at esp0: 8 targets, 8 luns per target
probe(esp0:1:0): max sync rate 5.00Mb/s
sd2 at scsibus2 targ 1 lun 0: <MAXTOR, 7290-SCSI, 2065> SCSI1 0/direct fixed
sd2: 276MB, 1751 cyl, 4 head, 80 sec, 512 bytes/sect x 566456 sectors
probe(esp0:4:0): max sync rate 6.25Mb/s
esp0: illegal command: 0x42 (state 2, phase 3, prevphase 1)
esp0: SCSI bus reset

I have sd0 and sd1 pinned down to drives on mesh0 in my kernel
config, sd2 is the one that works, so what's up with that device at
esp0:4:0? It is the same 500 MB SCSI-2 drive that was once the
internal drive on this 7500, but it's in an external case now. It did
once work on my mac68k machine, so I'm having a hard time
understanding what's making the kernel freak out now.

4) Unrelated to the above, what SCSI tape drives are tested and
useable with macppc, if any? Would it help someone's kernel work if I
picked one up and did some testing with it? (I mean, I want a tape
drive anyway, so...)

       ~ g r @ eclipsed.net

PS, anyone interested in a 150 MHz 604 daughtercard for the 7x00 or
8x00 series macs? I've got one to spare now... (I'm not joking, let me
know if it'd help you out, it's your for cost of shipping.)