Are different encoders compatible?

[Ted Dunning]

If I create 6 + 6, 6 + 4 and 6 + 2 (data + parity) encoders, will the first two parity blocks be identical for all three?

[Klaus Post]

As far as I can tell the Cauchy matrix is, but test it out anyway I may be wrong.

[Ted Dunning]

Very cool. Interesting possibilities arise from this.

[Ted Dunning]

Just to finish off the story, I checked the results and

enc1 := reedsolomon.New(12, 2)
enc2 := reedsolomon.New(12, 4) 

do actually seem to produce the same first two parity blocks. I checked this for 2,3,4,6,12 parity blocks and the encoders all seem to produce the same parity blocks where there is overlap.

I interpret this as the underlying code using the same parity generating matrix and simply truncating it as needed to match what is requested. This pretty much explains why speed is inversely proportional to number of parity blocks.