Carl-Uno, here is my response to your questions...
1) Is it really necessary to keep the "Validate-Job" operation as a MUST to
implement? The "Get-Printer-Attributes" operation seems to provide all the
functionality that is needed.
HRL> Validate job is intended to pertain to more than just printer attributes.
It should also cover print job attributes (like n-up, for example). Isn't
Validate-Job akin to checking the "job ticket" whereas Get-Printer-Attributes
is akin to determining the device configuration?
2) Can you implement the operations "Create-Job", "Send-Document" and
"Send-URI", without the need to support multiple documents? This could be
useful for environments where you have long jobs, but do not need support
for multiple documents.
HRL> The model document supports the notion of a Create-Job operation followed
by only one Send-Document operation as semantically equivalent to a Print-Job
operation. It cautions regarding performance, however. If you are asking is it
ok to support Creat-Job, Send-Doc with only one document - Yes. If you are
asking is it ok to support Create-Job but LIMIT Send-Dco to only one
document... I'd say that would be a non-no!
3) What was the rationale for making the "printer-up-time" attribute a
REQUIRED attribute, considering that the other 3 attributes
"time-at-creation", "time-at-processing", and "time-at-completed", with
which it is associated, are all OPTIONAL?
HRL> Don't know for sure but I suspect this attempts to make a running "time
marker" available for monitoring, tracking accounting etc... without mandating
all the possible time recording points on each IPP device. This si somewhat
analogous to the sysUpTime concept in MIB-II.
Harry Lewis - IBM Printing Systems