Shifting from the compressed file to the decompressor is totally allowed. What is not is shifting it to the filesystem. For example, he could have named the d

Shifting from the compressed file to the decompressor is totally allowed. What is not is shifting it to the filesystem. For example, he could have named the decompressor file with the first 512 bytes of data and then the decompressor concatenates the filename with the rest of the data. However the filesystem is still storing more data than it was before.