This GEOS program provides an easy way for users to make patches in existing printer drivers to either fix problems or enhance their operation.
Programmers will find it useful to convert a printer driver into standard Commodore machine code so that it can be dis-assembled and printed out using a non-GEOS monitor (geoDebugger does not provide this capability). They can then use this program in the GEOS environment to make all the necessary patches and print out a list of instructions which can be communicated to other users who can then patch their own copy of the original driver. It can also be used to compare an existing patched driver with its original to find out how the "experts" do it.
Terry Mills, the foremost printer driver patcher, has tested this program and had this to say, "Great program! I wish I'd had it when I was working on my first double-strike and quad density printer drivers in the fall of 1986!"
Here is an example of what the patching instructions could look like. This one starts with the Epson FX-80 driver which "fakes" NLQ print mode using the codes for emphasized (ESC-E) and double-strike (ESC-G). These patches send the true NLQ code (ESC-x1) which most Epson compatibles now recognize:
Old Driver Name: Epson FX-80
Old CRC Code: 82a1
Old End Address: 7b51
New Driver Name: Epson FX-80(NLQ)
New CRC Code: c63b
New End Address: 7b51
Number of Patches: 3
7a15 47 00
7a16 1b 01
7a17 45 78
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What follows are not GH Wells comments, but were added later to give insight into the use of this programming/patching too
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What follows are not GH Wells comments, but were added later to give insight into the use of this programming/patching tool as use in the past on Q-link.
Origional, this file was upload to Quantum-Link. The file structure of the software libraries on Q-Link is a bit odd. Unlike most telecom services, Q-link allows the downloader or the uploader to attach a comment about the file directly to the file's description. The comment is in the form of a response to the description which others have the option to read. These responses are perament unless deleted by the SYSOP. This allows a user to post his opinions/reviews (good or bad) of the file for others.
Some programmers post their bug corrections, or warnings of hareware problems within this "Comment area". This save a downloader time and money if the bug was found after he downloaded a file. Instead of having to download a second time, he save the reponse (which almost always shorter than file downloaded) and correct the bug himself.
With the upload of PrintDvrPatcher, programmers could post bug fixes, and patches for use with oddball printers - directly into their file's Comment area. A programmer could upload a driver for a single printer, but within the comments he could post the codes to tweak the Driver for use with almost any other printer.
On CIS we'll need to improvise.
I suggest the 'fixes' be posted on the GEOS Programming boards, with the messages being saved as files in the libraries. A file could contain several different patches with the only limit being that each file cover only one type of Driver (different files for FX-80's, SG-10's, Color Printer's, etc.) A user could then download or buff the patches he might need.
(.txt)