Re: [Visualpython-users] sockets errors, vpython, and windows xp?

[Bruce S. <Bru...@nc...>]

The issue is with IDLE, a component of Python, not with VPython itself 
(though the basic architecture was originally developed by David Scherer 
when he was first building VPython), so you might want to bring this to 
the attention of the Python people.

Basically, the way IDLE works is that it spawns a separate copy of 
Python, which among other things keeps the running of your program at 
arm's length from the editing of your program, and so provides more 
security in terms of not losing your editing work. A socket is created 
to permit communication between IDLE and your running program. This 
socket is purely internal and makes no connection to the outside world, 
as you see in the boiler plate shown in the shell window when you first 
run from IDLE:

Personal firewall software may warn about the connection IDLE
makes to its subprocess using this computer's internal loopback
interface.  This connection is not visible on any external
interface and no data is sent to or received from the Internet.

Some firewalls ask you whether to continue blocking access or not for 
this program, and of course you should unblock.

A possibly separate issue is that occasionally one gets a socket error 
with no firewall issue in sight. The only way I know to clear this (at 
least on Windows, where most of my experience lies) is to log out and 
log back in (if the machine is configured that way) or to reboot.

Are these Windows laptops, Mac? Linux?

Bruce Sherwood

Pete Border wrote:

>Hi:
>
>I'm trying to have students use vpython on their own laptops, and 
>several of the newer ones are getting socket errors. The errors are not 
>very repeatable, but they seem to go away if ne turns off the firewall. 
>Is this a known problem, and ifso, how does one fix it?
>                            thanks;
>                                    Pete Border
>
>  
>