Descriptor List Compression Using Fibonacci Delta Encoding

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Solution Overview

Problem

In virtual tape library (VTL) systems, data de-duplication using partially ordered data sets results in large descriptor lists that consume substantial storage space and impact input/output operations, with conventional compression techniques offering minimal effectiveness due to their design for text files.

Innovation Solution

The system employs Fibonacci encoding for the first record, followed by calculating and encoding delta values between subsequent records, which allows for more efficient compression of descriptor lists by representing smaller values with shorter sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If data de-duplication is performed using descriptor lists in VTL systems, then storage space is saved by eliminating duplicate data, but the descriptor lists grow to tens of megabytes consuming substantial storage space and impacting I/O operations

Engineering Contradiction:
Improveduplicate dataVSAvoiddescriptor list size
Core Design Contradiction:
Loss of substanceVSQuantity of substance

Solution Approach 1:

The descriptor list is segmented into fixed-size blocks (e.g., 4KB blocks). Each block contains a limited number of descriptors, and the list is organized as a sequence of blocks rather than a single large structure. This segmentation limits the growth impact on I/O operations and allows efficient block-level management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts only the essential identifying information from full data segments to create compact descriptors. Instead of storing or processing complete data references, the system uses extracted fingerprint-like identifiers that are sufficient for de-duplication purposes, significantly reducing descriptor size.

Inventive Principle:
Principle #2Taking out (Extraction)

2Quantity of substance

If conventional compression techniques (LZW, GZIP) are applied to descriptor lists, then some compression is achieved, but the effect is minimal because these algorithms are designed for text files

Engineering Contradiction:
Improvedescriptor list sizeVSAvoidcompression effectiveness
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent changes the parameter representation from variable-length descriptors to fixed-width binary encodings. Each descriptor is represented as a fixed number of bits (e.g., 32-bit or 64-bit integers), transforming the data structure into a format that exhibits regularity and predictability, which is highly compressible with standard algorithms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Different compression strategies are applied to different parts of the descriptor list based on local characteristics. The patent uses dictionary-based compression for repetitive descriptor patterns and run-length encoding for sequences with repeated values, adapting the compression method to the local structure of the data.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8250043B2System and method for compression of partially ordered data sets
Publication Date: 2012.08.21 NETAPP INC
  • US8250043B2 patent drawing
  • US8250043B2 patent drawing
  • US8250043B2 patent drawing

AI summary

A system and method for compression of partially ordered data sets is provided. A first record of the data set is compressed by encoding the record using a Fibonacci encoding technique. Thereafter, for each subsequent record N, the N−1st record is subtracted from the Nth record before encoding the result, thereby allowing each subsequent record to store the difference (or delta) from the previous record.