LOL - very true, Clem. That was a shameless bit of self-promotion. From what I can tell, SIMH does not support a DH11. Yet.

But when is an emulated interrupt a bad thing? Except for the idle loop that may or may not be optimized, the rest is balls-to-the-wall CPU bound anyway. And these days, even emulated, we're orders of magnitude faster than the original hardware.

I recognize a familiar name in there ;)

But yeah, when a DZ11 was blazing away at 19200 baud (I hacked the TOPS-10 6.03A we had at LIRICS to support it), it made the system crawl.

Back to our regularly scheduled programming...

On 8/29/2018 3:30 PM, Clem Cole wrote:
Right but for goodness sake, try to make a DH11 work; not a DZ11!!!   Real DZ11'S were SW pigs and consumed a measurable percentage of a vax, particularly when running uucico(8) (they are interrupt crazy).   It is one of the reasons why the Unix community in those days always recommended Able DH/DMs on Vaxen.


On Wed, Aug 29, 2018 at 2:57 PM Arthur Krewat <> wrote:
Ala DZ11 support in the KS10 emulator of SIMH ;)

On 8/29/2018 2:50 PM, Clem Cole wrote:

We can take this off line.   As I said, it been done a numberof times with simh and the like.   The key is that simh creates a 'serial line' on a TCP port.    You tell UNIX to hang a login off it and then you telnet or whatever to that port.    The older system running in simh, thinks it has a serial line.   It pretty much just works; al biet is slow as hell and chews up a ton of resources.