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Hi Mike,<br><br>Thanks - that all makes sense to me.<br><br>Oh - the other new operation for System Service should be<br>Get-Printer-Attributes that allows a simple "ipp" URI (w/out<br>any authentication?) that does a "magic" redirect to the default<br>print service, right?<br><br>BTW - what *is* the default print service? The first one in<br>the list of configured-printers (services) that's of type print?<br><br>Cheers,<br>- Ira<br><br clear="all"><div><div class="gmail_signature"><div dir="ltr">Ira McDonald (Musician / Software Architect)<br>Co-Chair - TCG Trusted Mobility Solutions WG<br>Chair - Linux Foundation Open Printing WG<br>Secretary - IEEE-ISTO Printer Working Group<br>Co-Chair - IEEE-ISTO PWG Internet Printing Protocol WG<br>IETF Designated Expert - IPP & Printer MIB<br>Blue Roof Music / High North Inc<br><a style="color:rgb(51,51,255)" href="http://sites.google.com/site/blueroofmusic" target="_blank">http://sites.google.com/site/blueroofmusic</a><br><a style="color:rgb(102,0,204)" href="http://sites.google.com/site/highnorthinc" target="_blank">http://sites.google.com/site/highnorthinc</a><br>mailto: <a href="mailto:blueroofmusic@gmail.com" target="_blank">blueroofmusic@gmail.com</a><br>Winter 579 Park Place Saline, MI 48176 734-944-0094<br>Summer PO Box 221 Grand Marais, MI 49839 906-494-2434<br><br><div style="display:inline"></div><div style="display:inline"></div><div style="display:inline"></div><div></div><div></div><div></div><div></div></div></div></div>
<br><div class="gmail_quote">On Mon, Dec 1, 2014 at 10:58 AM, Michael Sweet <span dir="ltr"><<a href="mailto:msweet@apple.com" target="_blank">msweet@apple.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Ira,<div><br><div><blockquote type="cite"><span class=""><div>On Nov 26, 2014, at 11:51 AM, Ira McDonald <<a href="mailto:blueroofmusic@gmail.com" target="_blank">blueroofmusic@gmail.com</a>> wrote:</div><br></span><div>Hi Mike,<br><br><span class="">For operation (3) DeregisterOutputDevice, I was thinking of the case<br>where a running service (Print in the near term) crashes (and this is<br>noticed by System Service, let us hope). If DeregisterOutputDevice<br>is (redundantly) supported by the System Service, then an Administrator<br>could do the cleanup for the Infrastructure Printer (who might queue<br>jobs).<br></span></div></blockquote><div><br></div>Presumably DeregisterSystem is the way for the System service to clean up references to the output device in all services it manages, even those that have "crashed" (which is a state we don't really model semantically...) If you want to deregister from a single service, you talk to that one service.</div><div><br></div><div><span class=""><blockquote type="cite"><div>Or, I'm crazy, and the System Service would automatically do this<br>cleanup internally and no external operation needs to be exposed.<br>But that risks a Deregister when the crashed service can be<br>successfully automatically restarted by the System Service after<br>a brief interval of unavailability. <br></div></blockquote><div><br></div></span>I would assume that self-healing of this sort would be expected of a cloud/SDN solution, with notifications sent to the relevant admin/operator. And I don't think we can necessarily recover from all situations like this - the Proxy might well have gotten a response from its Deregister-Output-Device request, with the cloud service crashing after successfully sending a response, so we have to hope that implementations will provide a way to perform manual cleanup as needed...</div><div><span class=""><br><blockquote type="cite"><div>I have mixed feelings about the reliability (and advisability) of <br>automatic recovery by the System Service for crashed or stalled <br>Job Services.<br></div></blockquote><div><br></div></span>Typically servers will be restarted a certain number of times in order to provide continuous service, with an alert going out for each crash/failed restart. And such things are typically configurable by service and various events - I have such things setup with our <a href="http://PWG.org" target="_blank">PWG.org</a> server instance, for example...</div><span class=""><div><br></div><div>
<div style="color:rgb(0,0,0);letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;word-wrap:break-word">_________________________________________________________<br>Michael Sweet, Senior Printing System Engineer, PWG Chair<br></div>
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