[evla-sw-discuss] An "In Use" flag for the MIB interface

[Hichem Ben Frej]

Kevin,

Thanks for you input.

As proposed, 2 or more processes running on the same host will have 
equal access rights. Any MIB locked by one process is accessible for all 
the other processes since, as you mentioned, the share the same IP address.

We referred to the case of servlet because the "real user" in this case 
is not the servlet but the user that is connected to the servlet.
Lets say that a servlet is running on a server S. User A connects to S 
through the browser. A sends a lock command, if available. The IP 
address used for the lock is the IP address of the machine S on which 
the servlet is running. Let say user B connects to the same servlet 
running on S.  User B has unlimited access to the MIB locked by user A 
since all the commands sent, through server S, have the right password 
ie. the same IP address. It is similar to the case mentioned above.

Thanks,

Hichem

Kevin Ryan wrote:
> Hichem,
>
> I think this is an excellent implementation of the lock - it is nice  
> and simple.
>
> Are there situations where two different processes on the same client  
> would conflict (they would have the same IP address)?
>
> 'Left on locks' should simply be handled like they are in the real  
> world; by policy -- "Anyone neglecting to remove his lock shall be  
> punished by not more than 6 months of attending code-walkthroughs"   
> It would be complicated to implement software that could prevent left- 
> on-locks.
>
> Also, I don't think I understand what you mean by the servlet/applet  
> thing not working.  Servlets, at least, should work because they have  
> knowledge of the remote client's IP address.  And I would think  
> Applets could send the client's IP back to the remote server (the MIB).
>
> Or am I misunderstanding something?
>
> Kevin
>
>
> On Aug 15, 2006, at 12:04 PM, Bill Sahr wrote:
>
>   
>> Any application that locks through a servlet or applet is not  
>> guaranteed
>> to have exclusive use of a lock because all other applications going
>> through the same servlet or application will be seen as having set the
>> lock, i.e., will have the same originator IP address (the password).
>>     
>
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>   


-- 
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Hichem Ben Frej - hbenfrej at aoc.nrao.edu

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