[Simh] porting simh to plan9

[Fernan Bolando]

On Mon, Dec 20, 2010 at 12:57 AM, John Floren <slawmaster at gmail.com> wrote:
> On Sun, Dec 19, 2010 at 11:46 AM, Holger Veit
> <holger.veit at iais.fraunhofer.de> wrote:
>> Am 19.12.2010 15:10, schrieb Fernan Bolando:
>>>
>>> after some debugging, I finally know what is causing simh to become
>>> non responsive.
>>> the good news is simh25 can easily be compiled through plan9 ape
>>> compatibility. The bad news is poll_kbd is blocking in plan9 so it
>>> does not return untill you press crriage return. commenting out
>>> poll_kbd allows the pdp11 to boot and show it's prompt but you will
>>> not be able to send keyboard command. it also crashes a few seconds
>>> after that so after fixing the nonblocking problem something might be
>>> broken
>>>
>>> so i need a plan9 version of poll_keyoard or get telnet approach working.
>>>
>> Plan 9 might use the common Unix method of non-blocking I/O, namely, open
>> /dev/tty (which is
>> usually connected to the keyboard) and use an ioctl to switch it to
>> nonblocking. Under Unix, this
>> is FIONBIO.
>>
>> Holger
>
> We don't have /dev/tty or ioctls; we can't expect anything from Unix
> to carry over. I expect one of the first things is to put /dev/cons
> into raw mode so you can get character-at-a-time... not sure what
> comes next.
>
> Telnet might be better in the long run.
>

I got the blocking i/o working by implementing a simple kbhit code. so
it's working now. I am now looking at a wierd issuance of halt when
its sitting idle for too long. I am thinking that i might be related
to a memory leak that i was seeing with simh25+9vx. I am now running
simh38 and it no longer gives a memory leak, but it seems to register
a halt command. It migh just be 9vx and I will not actually see it in
a real plan9 system. I am away from my plan9 server so for now it's
being tested on 9vx virtual plan9.

I dont have experience with sockets in plan9 or unix so I am putting
that a side untill i can get some reading done on the subject.