Printer does not print

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Last Updated: 5th December, 1994


Symptoms

Spooler reports a printer as off-line or out of paper, or printer accepts data but never prints. Printer works fine under DOS or previous version of OS/2.


Hardware

Various printers, including an Oki OL400 (emulating HP LaserJetII), a real HP LaserJet II, HP PaintJet and PaintJet-XL, a HP Deskjet Plus, Panasonic models KX-P1124i and KX-P1123, an NEC SilentWriter 2/M90 (PS laser printer), and a Fujitsu 7100PS. Not to mention Lantastic printer support.


Problem

Under OS/2 2.x, the low-level printer support was interrupt driven, using IRQ7 for LPT1 and IRQ5 for LPT2. This was good (low overhead, good throughput) and bad (IRQ conflicts with SoundBlasters and other adapters, no choice on IRQ used, printer adapters and cables which worked under DOS might not under OS/2).

Beginning with OS/2 Warp Version 3, the OS/2 Development staff introduced a "stealth" enhancement: the default low-level printer support is now handled by periodically "polling" the printer port to see when it can accept the next character. This is good (allows a lot of printers, cables, and LPTx adapters to work under OS/2 that might not otherwise) and bad (increased overhead).


User feedback seems to be mixed. Some printers seem to work acceptably with OS/2 polled printing, some do not.


Fix

You can re-introduce interrupt-driven printer support by editing your OS/2 CONFIG.SYS file to add a /IRQ to the PRINT01.SYS or PRINT02.SYS statement. For more information, type HELP BASEDEV at a command prompt and then do a Search for PRINT01.


Notes

Human nature being what it is, there are more postings describing printer problems than reports of printers working roperly with the new polled support. At first I thought it might be related to the new OMNI driver (another Warp "stealth" feature), but I don't believe that the HP Laserjets or PostScript printers use the OMNI driver. If anyone can come up with specific criteria that can determine whether a given printer or LPT1 adapter will work properly using Warp's default "polled" printer support, please let me know.

Although it is nowhere explicitly stated, it appears that there is still no choice on printer IRQs if you use them. With the /IRQ parameter in place IRQ7 will be used for LPT1 and IRQ5 for LPT2.



Frank McKenney