From: Gary Wright <gwtmp01@...>
Date: 2007-10-12T00:17:11+09:00
Subject: Re: Inter-Process Messaging


On Oct 10, 2007, at 6:04 PM, Francis Cianfrocca wrote:
> On 10/10/07, Gary Wright <gwtmp01@mac.com> wrote:
>>
>>
>> Daniel DeLorme wrote:
>>> Right now I can think of some messaging primitives:
>>> - TCPServer/TCPSocket
>>> - UNIXServer/UNIXSocket (unstable?)
>>> - IO.pipe (doesn't need port#)
>>> - Process.kill (impossible to send data)
>>
>> Not that it would be useful but I guess that if you used
>> two different signals (say SIGUSR1 and SIGUSR2) then you've
>> got a method of communicating a sequence of binary digits
>> to another process.  If you've got a reasonably accurate
>> way of timing things you could just manage this with a single
>> signal because the absence of the signal could be detected.
>
> There's some cleverness to this idea but I would avoid it. Signals  
> interact
> very badly with threads and other system facilities, they're not
> deterministic, they have serious platform dependencies among different
> Unixes, they're heavyweight (resource intensive), and they have  
> difficult
> APIs.

I guess I should have added some smiley faces. :-)

There is a whole area of computer security though, covert
signaling methods, where low bandwidth, unreliable communication paths
are still of interest.