fratus@niaid.nih.gov (John Fratus) (12/12/90)
I'm trying to get my A/UX 2.0 equipped IIfx to print to a Tektronix Phaser PX color PostScript printer. The printer is connected directly to the ethernet with one of those EtherPrint boxes that Dayna is selling. If I'm printing from the "Mac" side of things (like if I'm printing from Word or something), everything works fine. Things print. However, when I try to use lpr or atprint to print from the "Unix" end, nothing prints for a _long_ time (tens of minutes), and then sometimes the job will print. Sometimes the darn thing will _never_ (at least _approching_ never!) print. We decided to see how things looked on the Ethernet, so we pulled ou a Sniffer and looked at the packets. What happens is this: o The Mac goes out and asks where the printer is o The printer responds o The Mac talks to the printer, and says "Open a connection" o The printer responds, and appears to say OK. o The Mac sends a reset. o The Mac again sends the "Open a connection" packet. o The printer again responds. o The Mac sends another reset. o Etc. Etc. Etc. o After a long time, instead of sending another "Open" packet, the Mac sends a "Tickle" packet, and then the printing proceeds normally. When printing from a "MacOS" application under A/UX, the "Open" sequence loops twice and then printing commences. The key to whether the sequence loops or not seems to be the "Wait Time" field in the "Open Connection Request" PAP header. If the field contains "0", the looping occurs. Any number > 0, things print. When printing from the Unix side, this field (almost) never changes from "0". I don't know why it does change when it does. When printing from MacOS-type programs, the field is 0 the first time through, and then changes to "2" the second loop through. I may be looking too deeply here, but what the heck... Anybody got any ideas? Thanks. - John (fratus@niaid.nih.gov)