[HECnet] SIMH VAX Project

[Johnny Billquist]

Hi. Apologies for coming in late. I'll try to answer several mails and questions at the same time here...

On 06/30/11 09:10, Mark Benson wrote:
On a semi-related note I noticed something installing 7.3 that it said not to install DECNet-Plus if you want to use DECNet-PhaseIV. Since HECNet is PhaseIV I didn't install Plus on the VAX EMulator, but I *did* IIRC on the Alpha. Will the Alpha need a re-install or reconfiguration of some kind to run on HECNet?

DECnet-Plus is pretty much DECnet IV compatible as far as interoperability goes. What differs is the way you manage the whole thing, as well as all the extra stuff that is in DECnet-Plus. But you can run DECnet-Plus just fine on HECnet, and I think one or two actually do. However, most people just find it overly complex to manage compared to DECnet IV, without any tangible benefits.

As for the "problems" with NetBSD, I think I saw that you figured out that simh needs to be run as root for it to work. That should be pretty obvious, since it would be a big security problem if everyone was allowed to sniff the ethernet cables at will. Also, it is "ra0" and not "/dev/ra0". Ethernet device names are not paths that exist in the file system. It should be obvious if you actually do an ls on /dev... There isn't any /dev/ra0 (well, unless you happen to run a VAX with NetBSD, in which case there would be a /dev/ra0[a-h] for a disk drive.

Yes, both simh and the machine itself can share the same ethernet port, with the possible problem of talking between those two entities. But from other machines, there will not be any problems (this is not an aspect of the pcap library, but actually a thing related to the Berkley packet filter (bpf) which pcap use, and also to the underlying ethernet driver and possibly the hardware itself).

However, there is in general a bigger problem with simh, NetBSD and DECnet, in that DECnet expects to be able to change the MAC address of the ethernet interface, and the ethernet interface on NetBSD does not have a way of doing this. I'm not sure if simh have a workaround for that, but I would be suspicious that maybe DECnet will not work under simh on NetBSD. IP will work fine, however, since it does not try to do such a trick.

As for compiling, yes, the pcap library have to be around already at compile time, or the compilation will fail (obviously). Not withstanding shared libraries and all that, the header files, which are also installed along with the pcap library itself, are needed for compilation. And at link time, the library is checked for some information at that time also. That said, libpcap is a standard component of NetBSD, and there is no need to install another version from pkgsrc.

> Hi Mark, you do know that one of the symptoms of being a VMS bigot is that unixes look alike :-)
That's kinda like confusing VMS and Windows NT because they both have something to do with Dave Cutler and associates ;)

Well, not really. Linux and Unix are written by different people, but they are based on the same basic design. VMS and WNT was designed by the same person, but not designed in the same way.

Anyone using one Unix system will feel pretty much at home with any other Unix system. Yes, some details differs, but almost everything will be the same, down to using the same shell, similary file system layout, and so on... Try that between VMS and WNT if you dare... :-)

	Johnny