netboot behavior

Started by dross, September 26, 2021, 02:16:33 PM

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dross

Hey there, I just bought a NeXTcube & am playing around a bit. My setup: https://twitter.com/randomdross/status/1416190064632111105

So...  I'm looking into netbooting this box and I'm seeing some strange behavior.  When I use "ben" from the ROM monitor or set the default boot device to "en", I only see a BOOTP packets once every few attempts.  When I do see a BOOTP packet, I also see that the link shuts down immediately after it gets sent out.

I do see that if I boot off the disk, the network comes up, stays up, and BOOTP packets come out every few seconds.  So it doesn't appear to be a hardware problem.

Anyone know why I might be seeing this weird behavior when I attempt to netboot?

Dave

andreas_g

Hello Dave,

what Cube are you using? 68030, non-Turbo 68040 or Turbo 68040? Is it connected via ThinWire or Twisted pair Ethernet? I can do some tests after knowing your configuration.

dross

Hey Andreas, it's a turbo 68040 cube with TP ethernet.  I made a bit of progress on this since my original message.  I was attempting to netboot the NetBSD bootloader, and I was ultimately successful in doing so, though I have yet to get the bootloader to successfully load a kernel image.  I think this is likely a NetBSD issue though, as NetBSD was supported really well on the NeXT and in particular the turbo cube, as far as I can tell.

I did observe that netbooting is very flakey on this hardware.  When the boot device is set to "en" it's never successful on booting off the network on first boot.  If I do a command-` to get to the ROM monitor, I can often get it to boot off the network into the first-stage bootloader.

I do know the networking hardware on this box is OK given that I'm able to boot into NextStep and use the network just fine from there.

Dave

andreas_g

The ROM on the Turbo uses a quite strange procedure to detect which interface is connected. It might just be an issue with the signals on the cable. Did you try btp as boot command? That should try twisted pair first, while ben tries thin wire first and might fail to switch.

dross

I did try btp and it worked but I don't think it was any more reliable than ben unfortunately.

andreas_g

I am not an expert with these things, but maybe the open ThinWire port needs some termination which might be missing or faulty?

dross

Seems like a good idea.  I will get a 10base2 terminator and try it out.  Thanks!

andreas_g

I hope it works! Do you only have a setup with NetBSD? In case you can also netboot NeXTstep and you have the appropriate setup for capturing network traffic you might be interested in this: http://www.nextcomputers.org/forums/index.php?topic=2642.msg27291#msg27291