please only answer this question if you can all of them they all related to one chapter

please explain the following :

1) what is run length encoding and an example of how to do it if you have a sequence of data and what are the advantages and disadvantages?

2) explanation of Huffman coding and an example of it

3) what is Internal and external fragmentation

what is Reclaim space: avail list operations, replacement strategies

How to find things quickly in fixed length record and variable length record, whats the difference?

what is Keysorting?

use as much details and explaination as possible