Editing Commodore 1541 (section)

== Uses ==
Early [[copy protection]] schemes deliberately introduce read errors on the disk, the software refusing to load unless the correct error message is returned. The general idea is that simple disk-copy programs are incapable of copying the errors. When one of these errors is encountered, the disk drive (as do many floppy disk drives) will attempt one or more reread attempts after first resetting the head to track zero. Few of these schemes have much deterrent effect, as various software companies soon released "[[Bit nibbler|nibbler]]" utilities that enable protected disks to be copied and, in some cases, the protection removed.

Commodore copy protection sometimes fails on specific hardware configurations. ''[[Gunship (video game)|Gunship]]'', for example, does not load if a second disk drive or printer is connected to the computer.<ref name="bobo198802">{{cite news |url=https://archive.org/stream/1988-02-compute-magazine/Compute_Issue_093_1988_Feb#page/n51/mode/2up |title=Project: Stealth Fighter |work=Compute! |date=February 1988 |access-date=2013-11-10 |author-last=Bobo |author-first=Ervin |pages=51}}</ref> Similarly ''[[Roland's Ratrace]]'' will crash if additional hardware is detected.  The tape version will even crash if a floppy drive is switched on while the game is running.