[Coco] Telnet to your CoCo.. and invite 6 of your friends
Boisy G. Pitre
boisy at tee-boy.com
Tue Dec 1 16:36:50 EST 2009
On Dec 1, 2009, at 3:31 PM, Joel Ewy wrote:
>
> In theory, you can add new system calls by adding os9p[x] modules, and there are versions of os9p3 out there. So your question is a good one: what if os9p3 implemented the F$SETID call? Could that simply override the one in os9p2? That would be interesting.
>
> JCE
That's exactly what would happen... when the kernel scans for krnpX modules, it will call the os9 F$SSvc system call to install the system calls in that module; if any of those system calls reuse an existing system call number, then their address will overrwrite the address stored in the system call jump table in RAM.
It's a great way to extend the operating system.
--
Boisy G. Pitre
http://www.tee-boy.com/
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