Need explain compression

[tomi2k9]

Hi guys. I found one script, but dont know part of this:

arc a -ep1 -r -w.\ .\%arc% -msrep:l256+lzma:a1:mfbt4:d200m:fb128:mc1000:lc8

What is mean l256?

[minh_k43sj]

Hi guys. I found one script, but dont know part of this:

arc a -ep1 -r -w.\ .\%arc% -msrep:l256+lzma:a1:mfbt4:d200m:fb128:mc1000:lc8

What is mean l256?

memory ram to compress & decompress