papif checksum errors
Peter Campbell
> I am having trouble printing to a certain laserprinter.
> when I try to use papif it just reports a lot of checksum errors
David Hornsby pointed out that this is a FAQ and that in the case of
such #*(%&@! printers a fix is to disable checksum checking using
the -k option.
Thanks David.
Peter Campbell pe...@ml.csiro.au
CSIRO Marine Labs, Hobart, Australia
Peter Campbell
to a Webster Multigate. I can print to it from any LocalTalk or
EtherTalk Mac around the place but when I try to use papif it just reports
a lot of checksum errors:
Checksum error: Incoming: 175, calculated 35f7 [6494.168]
Dropping packet
Checksum error: Incoming: f4e6, calculated 7a28 [6494.168]
Dropping packet
Checksum error: Incoming: 175, calculated 35f7 [6494.168]
Dropping packet
and nothing gets printed. Other printers on the same network work.
The same printer on another LocalTalk network does not work.
The printer is a NewGen TurboPS/660. Any thoughts.
Richard E. Brown
Some information about checksums. As of this date, I know of these
products which have problems with DDP Checksums:
* AppleTalk Imagewriters have a bug in the checksum computation
routine.
* LaserWriter NTR's also have a bug in the checksum code.
* All AppleTalk drivers before AppleTalk 57.0.4 had a bug which didn't
handle
DDP checksums.
* I know of several third-party AppleTalk vendors (whom I won't
embarass while
they're working on a fix) whose products don't handle DDP Checksums
properly.
Anyone see a pattern here?
I found an Extension on the net called ForceDDPChecksum. It forces
*all* packets sent by your Mac to contain a DDP checksum. Inspection
with ResEdit shows that it patches the Control call for the .MPP
driver, and sets the "Compute checksum" flag for each DDPWrite. Since
it's short, I've attached a binhexed copy.
Protect yourselves against bad AppleTalk protocol implementations!
Install this on your Mac, and, whenever a new piece of equipment
arrives, you'll know right away if its checksum code works.
Rich Brown E-Mail: richard...@dartmouth.edu
Manager of Special Projects AppleLink address: RICH.BROWN
Dartmouth College (note new ALink address)
Kiewit Computer Center Telephone: 603/646-3648
Hanover, NH 03755-3523 USA Fax: 603/646-2810
------ ForceDDPChecksums follows -------
(This file must be converted with BinHex 4.0)
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PBR9RCf9b)'PZFh4KE'aPC#"dEb"SB@jNE'8JC'9LG@F!!!%Q6PEri%MR"aK#Tbm
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