A
Some time back, I figured out how to "hack" into a SLC with the "Access Denied" bit (S:1/14) bit set, as well as bypassing any passwords that the programmer may have set. For those not familiar with this feature, if the bit is set, the RSLogix software will not allow you to go online with the SLC, nor upload the program unless you have the same version of the code as is in the PLC. Allen-Bradley's intent with this bit is for OEMs to sell proprietary code without fear of it being copied (read: stolen), or the warranty voided because of software changes. It can also be used by a company to keep unauthorized users out of the SLC, but leave RSLogix installed on the PC. Rockwell publicly states that the only way to clear the bit without the original code, is to pull the battery, wiping the memory. They are wrong. It can be done (easily, if you know how) while the processor is up and running, without even stopping production. I've been tempted to publish the technique in some public forums (such as this one), but haven't for two reasons. The first is mercenary: why give away something that I can sell ;-); and the second is ethical: OEMs and SIs do have a right to keep their proprietary code secret. On the other hand, the technique is useful to a company who DOES own the rights to the software, but lost the copy that allows them online, or which suffers from an employee who accidentally or maliciously set the bit, and now cannot connect. I've considered selling a retrieval service to those companies who might need it (and if you do need it, contact me offline (Mailto:[email protected] (blatant plug, ;-) )), but the ethical dilemma is: HOW DO I TELL IF A COMPANY REALLY OWNS THE SLC CODE ? I feel morally bound, as a member of the community of integrators, not to steal someone's intellectual property, without at least an implied consent (such as the code to be found in this forum's PLC Archive). The "Access Denied" bit implies a negative consent. So, I would want any company that I perform this service for to prove that they SHOULD have the source code, either because they paid for it, or because they developed it themselves. But what constistutes proof ? How can I be sure, that I'm not ripping someone off. Or (for you open source proselytizers out there), am I wrong about the ethics? Does owning the functioning SLC automatically give the owner of the SLC the right of full and unfettered access to the code (provided they pay me to fetch it for them) ? Opinions? Allen Nelson