[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.

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

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