All,
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JKM> As far as deriving base constraints goes, to me the real question =
is:
JKM>
JKM> Must an "IPP Printer" must be able spool print jobs?
JKM> I would like to see an answer of "Yes", but clearly this is where =
desktop
JKM> printers (and many, if not most, network printers) fail to perform. =
And I
JKM> believe this is usually the reasons behind most case of "we can't =
do that
JKM> due to printer limitations."
SAI>I fail to see why a "yes" answer matters? If someone decides to =
implement
SAI>IPP in a printer that can not spool, what changes? If it is too =
busy
SAI>processing one job and another comes in from another client, it =
returns a
SAI>"busy" or a "out of spool space" just as in the case where a server
SAI>implementation supports 2000 spooled jobs and the 2001st job comes =
in. =20
<snip>
SAI>Will anybody implement IPP in a printer like this? Probably not. =
Does the
SAI>model preclude them from doing so? No. Will this type of printer =
ever be
SAI>used as as a shared network printer? Probaly not, but if it is, and =
it does
SAI>not embed IPP then it can be front ended by a "server" that does.
__________
PJZ:
I have been listening. I am prototyping IPP on a printer that can only =
accept and process a job at a time. I chose this printer specifically =
to check the lower bounds of an IPP implementation. I have to agree =
with Scott. Spooling is not the printer feature that determines if a =
printer is capable of supporting IPP. IPP will be sitting (somewhere) =
on top of TCP. The flow control capabilities of this layer of the =
protocol should allow me to gate the inflow of PDL data while the =
printer "catches up" with the PDL stream. I also have the job-k-octets =
to limit the job size for a low-end printer. =20
This class of printer will not be IPP feature rich. The printer itself =
will not be feature rich. It is true some clients will be denied =
service while the printer is busy. All services must handle the =
"capacity + 1" problem. IPP seems to handle this problem. There is =
still the issue for the application to determine when it should time =
out. IPP level print job submission operations should help accomodate =
application level timeout detection. We will have to see where the =
print operation semantics discussion ends up.
Will this type of printer be used as as a shared network printer? Yes =
it can, if the workload is low enough. If IPP service is not available =
often enough for the site's needs, an IPP spooler can be put between the =
client and the printer. A bigger printer could also be used.
The factor that will determine if a printer can be IPP compliant will be =
the complexity of IPP, IPP conformance specification, and the available =
printer resources that are available for IPP.
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