- [x] file operations
  - [x] write to file (at index)
  - [x] read file
- [x] a tape type - representing a file?
- [x] a record type - x1,x2,x3,x4,x5
  - [x] comparing records
- [x] buffer quick sort
- [x] configuration
  - [x] cmd args - man getopts
- [x] file input
- [ ] keyboard input
- [x] stage 1
  - [x] reading chunks
  - [x] sorting
  - [x] writing runs
- [ ] stage 2
  - [ ] implement a min heap with following operations
    - [ ] pop
    - [ ] push
  - [ ] step 4
    - [ ] split the buffer into chunks of size n, and (b-1)n
    - [ ] create a min heap of size (b-1)n
    - [ ] populate the heap with (b-1) runs of n elements (each from a different file)
    - [ ] find a way to mark if a last element from a certain file has been popped
    - [ ] when a merged buffer is full, write it to file
    - [ ] pop off the top element until there are no more elements from a certain array
    - [ ] load another run from that file, and rehapify
    - [ ] repeat untill all files empty
    - [ ] the resulting file should get the new smallest filename in tmp dir

  - [ ] multiway merge
  - [ ] writing larger runs
  - [ ] repeat untill done

- [ ] counting read, and write operations
- [ ] testing
- [ ] report