Bill,
> On Dec 5, 2025, at 8:23 PM, wamwagner at comcast.net wrote:
>> All,
> I realize that my questions are perhaps tangential to the primary purpose of the IPP Firmware Update Extensions document, but the allusion to firmware as a resource handled by the IPP System Service under Directed Firmware Update (Section 4) led me to revisit that document, and I would appreciate someone clarifying a few points.
> • Firmware Update Extensionin the Directed Firmware Update discussion states “If the Output Device implements the IPP System Service [PWG 5100.22], then it can receive the Firmware Update from the Management Device”
> • My understanding is that the System Service is more akin to the Management Device in Figure 1 than a printer, and is intended to support multiple printers.
A System Service *can* take that form - the model is abstract enough to allow it - and you might in fact have a hierarchy of System objects as a function of fan-out/in. At its most basic level a System Service manages the various services provided by a multi-function device - print, scan, copy, fax-in/out, etc. - along with the resources and subunits that are shared by those services.
> • The operations applicable to firmware download (Create-Resource, Send-Resource-Data, and Install-Resource) are. I believe, System Service but not Printer operations.
Correct, but resources can be assigned/added to Printers using the Allocate-Printer-Resources operation.
> • Would it be valid to implement some subset of the System Service capability in an individual printer?
INFRA provides an out-of-band interface for a Proxy to upload Printer resources such as icons, strings, ICC profiles, and so forth. This was mainly because we didn't have the System Service specification written at the time but also to allow for "simpler" INFRA implementations.
FaxOut and Scan coordinate with Print for DNS-SD registrations, regardless of the present of a System Service.
So there is certainly the precedent to allow for a Printer to provide System-like functionality when a full System Service implementation would be overkill.
> • If one did implement a System Service (which seems to me to be a very useful capability), and created, downloaded, and installed a resource in the System Service, how is this resource transferred to individual printers?
The Allocate-Printer-Resources operation.
> • And finally, the System Service absorbed much of the functionality of the previously defined Resource Service. I was of the impression that proprietary schemes were typically used for downloading resources. Out of curiosity, has there been any degree of implementation of the System Service in the industry?
I don't believe that there is widespread adoption, but there *are* a number of printers using my PAPPL software which implements most of the System Service, and that software is already widely used on Linux for Printer Applications and will be the basis of the CUPS 3.0 printing systems.
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Michael Sweet