Obviousness

Based on the provided prior art analysis, which has been validated by successful challenges at the Patent Trial and Appeal Board (PTAB), the claims of US Patent 5,490,216 are rendered obvious under 35 U.S.C. § 103.

Definition of a Person Having Ordinary Skill in the Art (PHOSITA)

At the time of the invention (prior to the September 1993 filing date), a person having ordinary skill in the art (PHOSITA) would have been a software developer with a bachelor's degree in computer science or a related field, or equivalent industry experience. This individual would have been knowledgeable about common operating systems (e.g., MS-DOS, Macintosh System 7), software distribution methods (e.g., floppy disks), and the prevalent problem of software piracy. They would be familiar with existing software protection and registration schemes, including the use of serial numbers, hardware fingerprinting, and remote activation.

Primary Obviousness Combination: Tan (WO 92/09160) in view of Joshi (US 4,688,169) or Pride (US 4,796,220)

The combination of the Tan reference with the teachings of either Joshi or Pride renders all independent and dependent claims of the '216 patent obvious. This was the core argument successfully used in PTAB proceedings IPR2014-01453 and IPR2015-01026 to invalidate all 20 claims of the patent.

1. What Tan Teaches

The Tan reference (WO 92/09160) serves as the primary and foundational piece of prior art. It discloses a complete software licensing and distribution framework that anticipates the core novelty asserted in the '216 patent's independent claims (1, 11, 17, and 20). Specifically, Tan teaches:

• Mode-Switching: Distributing software as a "shell" program that operates in a limited "demonstration mode."
• Remote Registration: Requiring the user to contact a remote registration authority to unlock the full "use mode."
• Local & Remote ID Generation: The user provides unique information to the local software. This information is also communicated to the remote authority. The software is unlocked only when an authorization code, generated remotely based on this same information, is provided back to the user and entered locally. This directly teaches the claimed concept of a "local licensee unique ID generating means" and a "remote licensee unique ID generating means" that must match.
• User-Unique Information: The registration and authorization process is based on information that is unique to the user or licensee.

Tan alone provides a blueprint for the entire registration process described in the '216 patent. The '216 patent's attempt to distinguish itself by claiming Tan requires downloading significant portions of the program is a minor implementation detail that does not overcome the fact that the fundamental registration and mode-switching method based on matching user IDs is disclosed.

2. What Joshi or Pride Teaches

The Joshi and Pride patents teach the one main element not explicitly detailed as a primary focus in Tan: generating a unique identifier for the computer hardware itself to "lock" the software to a specific machine.

• Joshi (US 4,688,169): Discloses a security system that relies on a "machine identification code unique to the machine."
• Pride (US 4,796,220): Discloses a method for creating a "digital fingerprint" of a computer by combining information about its hardware and system software.

Both references clearly and explicitly teach the concept of a "platform unique ID generating means" as claimed in the dependent claims of the '216 patent (e.g., claim 2).

3. Motivation to Combine

A PHOSITA in the early 1990s, starting with the licensing framework taught by Tan, would have been immediately confronted with the problem of a registered user simply copying the fully-unlocked software to another machine. Preventing this was a central challenge in software protection at the time.

The most common and logical solution to this problem was to tie the software license not just to the user, but also to the machine. The methods for generating a unique machine identifier as taught by Joshi and Pride were well-known in the art for precisely this purpose.

Therefore, a PHOSITA would have been motivated to combine the teachings of Tan with those of Joshi or Pride for a predictable and obvious improvement: to enhance the security of Tan's user-based licensing system by adding a layer of machine-based hardware locking. The motivation was simply to create a more robust copy protection scheme, which was a clear goal for any software publisher at the time.

Conclusion

1. Tan teaches the overall framework: A mode-switching system where full use is enabled only after a user-unique ID generated locally matches a key provided by a remote authority. This renders the independent claims (1, 11, 17, 20) obvious.
2. Joshi/Pride teaches platform identification: A method for generating a unique ID based on the computer's hardware to prevent copying.
3. The combination was obvious: A PHOSITA would have been motivated to integrate the well-known machine-locking technique of Joshi or Pride into the licensing system of Tan to prevent unauthorized copying of registered software. This combination directly arrives at the invention claimed in the dependent claims of the '216 patent, such as checking if the platform has changed on subsequent use.

The successful invalidation of all claims in IPR2014-01453 and IPR2015-01026, based on these exact references and this line of reasoning, confirms that the claimed invention was an obvious combination of known elements at the time of filing.