[HECnet] SIMH VAX Project

[Mark Benson]

On 2 Jul 2011, at 14:19, Johnny Billquist wrote:

No, they should not. The raw unformatted size is not something that is *ever* visible outside of the disk, and when you emulate the disk, you are not emulating the unformatted magnetic platters, but a block formatted device.

I see.

Curiousity is good. The thing you emulate is the thing that is visible at the disk contoller layer. So anything beyond that will (probably) be different from the thing you emulate. When you emulate a uVAX with an RA92 disk, simh will present you with a emulated KDA-50, on which there appears to be an RA92 connected. In the real world, the KDA-50 runs some sort of microcode, and communicates with the disk over SDI, which is a serial protocol using four coaxial cables. And the SDI protocol defines how the KDA-50 gets the RA92 to do all kind of operations.

One of these days I want to have a good look at a real VAX, they are such a departure from anything I've used :) Interesting that they use a serial disk communication system - where've I seen that crop up recently? ;)

But none of that is emulated, and there is no real point in emulating it.

So essentially you are only emulating the minimum needed to keep the VAX microcode and after that OS happy and working 100%.

Good to hear things are working now.
As for telnet vs. ssh. Well, ssh is safer, in that people can't sniff passwords easily over the network. If you worry about people doing that, then you might want to not use it. However, if your network is secure, then telnet isn't really an issue.

Inside my own network that's not an issue. Accessing it from the internet, not such a good idea. I can SSH the NetBSD   side though so I may just settle with using the 'local terminal' via screen and ssh when using the internet.

I don't think that Compaq have any version of SSH for VMS om VAX, but I haven't checked if anything was shipped after 7.3.
There are other options, though. tcpware comes to mine.

I was thinking TCPWare too - seems to be the only reference I can find   to SSH on 7.3.

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Mark Benson

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