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How LZ4 works (2016)

ticki.github.io

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Re: How LZ4 works (2016)

#6
post #5

It's amazing how something useful and innovative gets invented, and isn't so much as documented, let alone patented or published in a journal.

LZ4 is only one of the many variations on the basic principle of the LZ family of algorithms, which is to replace repeated sequences with references to where they were before.

What does amaze me a little, is the fact that the rather more complex Huffman algorithm was published and implemented decades before LZ.

The core idea of LZ, however, has been known for centuries: https://en.wikipedia.org/wiki/Iteration_mark

Re: How LZ4 works (2016)

#8
post #5

It's amazing how something useful and innovative gets invented, and isn't so much as documented, let alone patented or published in a journal.

LZ4 is only one of the many variations on the basic principle of the LZ family of algorithms, which is to replace repeated sequences with references to where they were before. What does amaze me a little, is the fact that the rather more complex Huffman algorithm was published and implemented decades before LZ. The core idea of LZ, however, has been known for centuries: https://en.wikipedia.org/wiki/Iteration_mark

Iteration mark is more similar to RLE than to LZ. LZ can copy from arbitrary points in the past.

Re: How LZ4 works (2016)

#9
post #5

It's amazing how something useful and innovative gets invented, and isn't so much as documented, let alone patented or published in a journal.

LZ4 is only one of the many variations on the basic principle of the LZ family of algorithms, which is to replace repeated sequences with references to where they were before. What does amaze me a little, is the fact that the rather more complex Huffman algorithm was published and implemented decades before LZ. The core idea of LZ, however, has been known for centuries: https://en.wikipedia.org/wiki/Iteration_mark

This is true, there is low algorithmic novelty in lz4.

However, that's missing the point: lz4's decompressor is simultaneously simple and also the fastest thing aroud, at least at the moment.

In fact, it is so fast, it can be used to accelerate local data transfers over "slow" links like bonded 10GBit ethernet and arrays of PCIe SSD's.

Re: How LZ4 works (2016)

#10
post #9

Earlier quoted context omitted.

LZ4 is only one of the many variations on the basic principle of the LZ family of algorithms, which is to replace repeated sequences with references to where they were before. What does amaze me a little, is the fact that the rather more complex Huffman algorithm was published and implemented decades before LZ. The core idea of LZ, however, has been known for centuries: https://en.wikipedia.org/wiki/Iteration_mark

This is true, there is low algorithmic novelty in lz4. However, that's missing the point: lz4's decompressor is simultaneously simple and also the fastest thing aroud, at least at the moment. In fact, it is so fast, it can be used to accelerate local data transfers over "slow" links like bonded 10GBit ethernet and arrays of PCIe SSD's.

Doesn't that also explain why it came later? The low compression ratio is useful nowadays, with large throughputs.
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