Obviousness

The obviousness of US Patent 9,116,908 under 35 U.S.C. § 103 can be assessed by considering the knowledge of a person having ordinary skill in the art (PHOSITA) at the time of the invention (priority date March 11, 1999) and the motivations to combine existing technologies to address known problems. The patent's own "Prior art keywords" and "BACKGROUND" section provide the basis for this analysis.

1. Level of Ordinary Skill in the Art
A PHOSITA in 1999 in the field of data storage and computer systems would possess knowledge of various data storage technologies (e.g., magnetic and optical disks, RAM), their performance characteristics (including bandwidth limitations), and established data processing techniques. This would include a solid understanding of data compression and decompression algorithms, both lossy and lossless, and their known benefits.

2. Known Problems in the Prior Art
The patent explicitly states the problems it seeks to solve within the prior art:

• "existing memory storage devices severely limit the performance of consumer, entertainment, office, workstation, servers, and mainframe computers for all disk and memory intensive operations."
• "magnetic disk mass storage devices currently employed... suffer from significant seek-time access delays along with profound read/write data rate limitations."
• "Faster disk access data rates are only achieved by the high cost solution of simultaneously accessing multiple disk drives with a technique known within the art as data striping."
• "Additional problems with bandwidth limitations similarly occur within the art by all other forms of sequential, pseudo-random, and random access mass storage devices."
  Essentially, the problem is the fundamental bandwidth mismatch between increasingly fast computer systems (e.g., PCI Bus at 264 MB/sec, local bus at 800 MB/sec) and slower storage devices (e.g., 10,000 rpm disk drives at 17.1 MB/sec).

3. Prior Art Elements (Based on "Prior art keywords" and Background)
The "Prior art keywords" are: "data", "data block", "compression", "compressed", "compression technique". The patent's background further clarifies the types and uses of compression:

• "Data" and "data block": These are fundamental units of information in computing and were universally understood.
• "Compression", "compressed", "compression technique": Data compression, both lossy and lossless, was a well-established field. The patent notes that "It is well known within the current art that data compression provides several unique benefits. First, data compression can reduce the time to transmit data by more efficiently utilizing low bandwidth data links. Second, data compression economizes on data storage and allows more information to be stored for a fixed memory size by representing information more efficiently." Specific lossless techniques like Huffman, Lempel-Ziv Dictionary Compression, arithmetic coding, data compaction, and data null suppression are mentioned as "well known within the art" in the context of the invention's decoder module.

4. Obviousness Analysis: Motivation to Combine Prior Art

The core of US 9,116,908 is the application of lossless data compression and decompression to accelerate data storage and retrieval by effectively increasing the bandwidth of slower storage devices. Given the known problems and the existing prior art, a PHOSITA would have been motivated to combine the elements as follows:

Combination 1: Data storage/retrieval with lossless data compression for increased capacity and effective throughput.

• Prior Art Elements: "data", "data block", "compression", "compressed", "compression technique", and known storage devices (as described in the patent's background).
• Motivation:
  1. To increase storage capacity: It was a long-standing and obvious motivation for a PHOSITA to apply "compression techniques" to "data" and "data blocks" to create "compressed data" for storage. This was done to maximize the amount of information that could fit on a fixed-size storage medium. The patent itself acknowledges this as a known benefit: "data compression economizes on data storage and allows more information to be stored for a fixed memory size by representing information more efficiently." For general data storage, lossless compression would be the natural choice to ensure data integrity.
  2. To increase effective data transfer rates (bandwidth): The patent explicitly highlights the "read/write data rate limitations" of storage devices as a significant problem. A PHOSITA would be well aware that compression reduces the amount of data to be physically transferred. The concept of using compression to increase effective throughput over a limited bandwidth channel was already established in other domains, such as network communications (e.g., modems using compression to achieve higher effective data rates over slower communication links). Extending this known principle to address the analogous bandwidth limitations of storage devices (e.g., disks, RAM) would be an obvious design choice. By compressing data before writing to a slow device and decompressing it after reading, a larger volume of original data could be effectively moved per unit of time, thereby "accelerating" storage and retrieval from the perspective of the uncompressed data. The patent's solution directly applies this known benefit of compression to solve the explicitly stated problem of storage device bandwidth limitations.

How this addresses the independent claims:

• Independent Claim 1 (Method for accelerated data storage and retrieval): This claim describes the entire process of receiving high-rate data, compressing it for storage in a slower device, retrieving the compressed data, and decompressing it for high-rate output. The motivation to use compression to overcome bandwidth mismatches for both storage and retrieval, a known problem and a known benefit of compression, would lead a PHOSITA to combine these steps. The specific ratios mentioned in the claim (e.g., compression ratio providing a data compression rate greater than the data storage rate, or output transmission rate greater than the data access rate) are merely the desired and expected outcomes when applying effective compression to achieve the goal of acceleration.
• Independent Claim 20 (System for accelerated data storage and retrieval): This describes a system with a "data storage accelerator" (comprising a compressor) and a "data retrieval accelerator" (comprising a decompressor). Once the method (Claim 1) is conceived as obvious, building dedicated hardware or software modules to perform these compression and decompression functions in the data path of a storage system would be an obvious engineering implementation for a PHOSITA. The patent itself mentions that such an implementation could use "dedicated analog and digital hardware circuits, central processing units, digital signal processors, dedicated finite state machines."
• Independent Claim 35 (Method for accelerated data storage): This claim focuses specifically on storage. The motivation to compress data to allow continuous storage of a high-rate input stream into a slower storage device directly addresses the "read/write data rate limitations" by reducing the actual amount of data written per unit time. This is an obvious application of compression to a known problem.
• Independent Claim 42 (Method for accelerated data retrieval): This claim focuses specifically on retrieval. The motivation to decompress retrieved data to provide a high-rate output stream, overcoming the slower retrieval rate of the storage device, is also an obvious application of decompression to address the same bandwidth limitations.

Conclusion on Obviousness:
Considering the widely recognized problems of storage device bandwidth limitations and the well-known benefits of data compression (both for capacity and effective throughput), a PHOSITA in 1999 would have been motivated to combine general data storage and retrieval practices with existing lossless data compression and decompression techniques. The goal would be to alleviate the identified bandwidth bottlenecks, thereby achieving an effective acceleration of data storage and retrieval. The claimed invention, therefore, represents an obvious application of known technologies to solve a known problem with predictable results, falling within the purview of 35 U.S.C. § 103.