On Tue, 22 Aug 1995 16:27:07 -0700 <[log in to unmask]> said:
>The so-called 'Jet Direct' 'protocol' is not much more than raw
>TCP to port # 9100. You can get fancy and use SNMP traps to get status
>messages (Out of Paper, etc.) back to the host, but I doubt that they
>will bother to do this.  [...snip...]
 
Since this was demonstrated in the booth at Interex and the info that the
representative provided matched my, umm, expectations, I guess I can
answer this now :-)  Larry Byler or others might give you more specifics.
For those printers that are equipped with a bi-directional I/O port (for
the case of external JetDirect cards) that can return printer status, yes,
they not only keep track but the spooler drivers have page level recovery.
If not, then yes, as you noted, it's just like a DTC connection and you
can lose data.  For example, the 5000/C30 does not have a bidirectional
interface; the 5000/C40 does.
 
>I hope that you will be able to share printers among multiple systems.
>To do this you have to close the connection to the printer when you
>are not using it, and be expecting that the printer will reject your
>attempt to connect to it if it is already busy, so you can retry
>periodically (there is no queueing mechanism). A poor implementation
>of Jet Direct spooling on the 3000 would simply cause the spooler
>to shutdown if it found the device to be unavailable and/or spam
>the console with messages to this effect.
 
Nope.  The system goes into a (configurable) timeout and retries the printer
every (configurable) 'x' seconds.  Spool file 'status' has been expanded to
return such information (such as waiting on printer).
 
>> I also want LPR/LPD, but the lab answer to this one is that lpr/lpd is
>> a file transfer protocol and not a spooler driver.
>
>It's true that LPR and LPD are not protocols that are designed to talk to
>printers directly, but are instead intended to get the output to a system
>that WILL send it to a printer. However many printer interfaces and
>'network print server' devices (including all of HP's own current line
>of Jet Direct interfaces) implement the LPD protocol right at the
>printer itself, to the distinction is not very clear any more.
 
My point exactly.  If you have WRQ's RNS/Windows TCP stacks, you get a free
lpd you could use to print from the host to your attached printer (in the
background).  More generally, there are shareware lpd's available for any
generic winsock.
 
>> Despite their answer,
>> I would like to see an LPR-type device class that would behave like a
>> spool queue and, for files READY and > OUTFENCE, would transfer to a
>> specified IP address using LPR protocol.
>
>Lots of 3rd-party solutions for this today of course (NBSPOOL, etc.),
>but it would be nice to have HP support the standard unix remote
>printing protocols directly.
 
Yes, but all 3rd-party solutions implement a periodic scan of the spool
queues looking for candidates.  It seems to be relatively easy to provide
a spooler output process which is awakened like an ordinary spool process,
but performs a raw lpr transfer.  I don't care if there's no print recovery,
just transfer the thing and go back to sleep.  I'm not looking for any
front-end formatting by this "lpr" equivalent, that can indeed wait for a
Posix 'lpr' extension.
 
[\] Jeff Kell <[log in to unmask]>