K12MIT on PDP-12

Vincent Slyngstad vincent.slyngstad at gmail.com
Wed Nov 24 07:22:41 CST 2021

On 11/24/2021 1:47 AM, Christian Corti via cctalk wrote:
> So, with the help of you here, I was able to create OS/8 LINCtapes and 
> to run SerialDisk. Everything runs very fine.


> Now comes the next thing: I want to have K12MIT, and it is no problem to 
> compile or load the program.
> *But*: When I start K12MIT I don't get the prompt. I see the welcome 
> message, and it correctly identifies the machine as a PDP-12, but that's 
> it. As I've found out it apparently overwrites its code, the processor 
> is looping around address 3600-3620. Examining the memory reveals that 
> the code at 3600 has been overwritten with junk. So it's clear that it 
> won't run anymore. What happens? Was anyone else able to run K12MIT on a 
> PDP-12?
> BTW the same binary runs fine on a PDP-8, be it a real machine or SIMH.

Are you running SerialDisk on the same DP12 that K12MIT is trying to 
use?  That might not work well, though I'm not sure why K12MIT would 
commit suicide about it.

I haven't had much use for K12MIT -- the tools that come with the latest 
SerialDisk can take apart and rebuild/modify bootable/server images, so 
I just copy whatever to or the directory those tools are using and 
rebuild the image (or re-explode the server image and copy it out, to go 
the other way).


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