From 2016 onwards, EMBS practicals are on our new wiki, at https://wiki.york.ac.uk/display/RTS/EMBS


This page will contain any general notices or clarification related to the EMBS 2015 assessment.

Current Notices:

  • There is a little confusion about the sizes of the mazes. In the breakdown of marks at the end, mazes are described similar to (1x1, 8x8). This means a maze made of one tile, and that tile is 8 cells by 8 cells. (4x4, 16x16) means a maze of 16 total tiles, where each tile is 256 cells. Look at the examples below.
    • Therefore, the maze sizes your system must handle are enumerated in the breakdown of marks at the back of the assessment.
      • 1 tile, where the tile is 8x8 cells
      • 1 tile, where the tile is 16x16 cells
      • 2x2 tiles (4 total), where each tile is 8x8 cells
      • 2x2 tiles (4 total), where each tile is 16x16 cells
      • 4x4 tiles (16 total), where each tile is 16x16 cells
      • 8x8 tiles (64 total), where each tile is 16x16 cells
  • Sometimes the server may appear to stop responding. This happened in the EMBSCoin and CatFacts lab sessions too. It is because a fellow student has accidentally sent a message with their source MAC address set to that of the server. When this happens, the network switches start rerouting all traffic for the server to that student. There is nothing we can do about this except wait until the switch times out, so please double-check the order of your source and destination MAC addresses!
  • In the worst case scenario, it is possible for maze solutions to be longer than the 1500 bytes that will fit into a single Ethernet frame. These mazes are rare, and if you encounter one simply discard it. All mazes presented in the demonstration will be solvable in a single frame.

Please remember that the assessment involves a lot of bespoke software, and whilst we have tested as much as is possible there is always a chance of a minor error. Please do not hesitate to contact Ian if you think that you have found an issue and we will get it resolved as quickly as possible.


Sample Mazes
To help you debug your system, two sample mazes are shown below.

Seed: 1234, Maze size: 3x3, Tile size: 4x4, Perfect
┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼
                │   │           │       │       │
┼───┼───┼───┼   ┼   ┼───┼   ┼   ┼───┼   ┼   ┼   ┼
│           │   │           │   │   │   │   │   │
┼   ┼───┼───┼   ┼───┼───┼───┼   ┼   ┼   ┼───┼   ┼
│           │   │           │       │   │       │
┼   ┼───┼   ┼   ┼   ┼   ┼───┼   ┼   ┼   ┼   ┼   ┼
│       │       │   │           │           │
┼───┼   ┼───┼───┼   ┼───┼───┼───┼───┼───┼───┼───┼
│           │   │   │           │   │           │
┼───┼───┼   ┼   ┼   ┼   ┼───┼   ┼   ┼───┼   ┼   ┼
│       │   │   │   │       │           │   │   │
┼   ┼   ┼   ┼   ┼   ┼   ┼───┼   ┼───┼   ┼   ┼───┼
│   │   │       │   │   │       │       │       │
┼   ┼   ┼───┼   ┼   ┼───┼   ┼   ┼   ┼───┼───┼   ┼
│   │           │           │   │               │
┼───┼   ┼───┼───┼───┼───┼───┼───┼───┼───┼───┼   ┼
│                   │           │               │
┼───┼───┼───┼   ┼   ┼───┼───┼   ┼───┼───┼───┼   ┼
│   │       │   │               │           │   │
┼   ┼   ┼   ┼   ┼───┼───┼───┼   ┼   ┼───┼   ┼   ┼
│       │       │           │   │   │       │   │
┼   ┼───┼───┼───┼   ┼───┼   ┼   ┼   ┼───┼───┼   ┼
│               │       │                       │
┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼

Seed: 3000, Maze size: 2x2, Tile size: 8x8, Perfect
┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼
│   │       │   │                       │                   │   │
┼   ┼   ┼   ┼   ┼   ┼───┼───┼   ┼───┼   ┼   ┼   ┼───┼───┼   ┼   ┼
        │   │       │       │   │   │   │   │       │   │       │
┼───┼───┼   ┼   ┼───┼   ┼───┼   ┼   ┼   ┼   ┼───┼   ┼   ┼───┼   ┼
│       │   │           │       │       │       │   │           │
┼   ┼───┼   ┼   ┼───┼───┼   ┼   ┼   ┼───┼───┼───┼   ┼───┼   ┼───┼
│           │   │           │   │   │           │       │   │   │
┼   ┼───┼───┼   ┼   ┼───┼───┼───┼   ┼   ┼───┼   ┼───┼   ┼   ┼   ┼
│   │           │               │       │   │           │       │
┼   ┼   ┼───┼───┼───┼───┼───┼   ┼───┼───┼   ┼───┼───┼───┼───┼   ┼
│   │       │       │           │           │           │       │
┼   ┼───┼───┼   ┼   ┼   ┼───┼   ┼   ┼───┼   ┼   ┼   ┼   ┼   ┼───┼
│   │           │   │   │       │       │   │   │   │   │       │
┼   ┼   ┼───┼───┼   ┼   ┼   ┼───┼───┼   ┼   ┼   ┼   ┼───┼───┼   ┼
│       │               │       │       │       │               │
┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼   ┼───┼───┼───┼───┼
│       │   │           │       │           │           │       │
┼───┼   ┼   ┼   ┼   ┼───┼   ┼   ┼───┼───┼   ┼   ┼   ┼   ┼───┼   ┼
│       │       │           │   │   │       │   │   │           │
┼   ┼───┼   ┼───┼───┼   ┼───┼   ┼   ┼   ┼───┼   ┼   ┼───┼───┼   ┼
│   │       │       │   │   │   │   │   │       │   │       │   │
┼   ┼───┼───┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼───┼───┼   ┼   ┼   ┼   ┼
│           │   │   │   │   │   │   │           │   │   │   │   │
┼───┼───┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼───┼───┼   ┼   ┼───┼   ┼   ┼
│       │       │   │       │   │   │       │   │       │   │   │
┼   ┼───┼───┼───┼   ┼───┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼   ┼
│   │               │       │   │       │   │   │   │   │       │
┼   ┼   ┼───┼───┼───┼───┼───┼   ┼   ┼───┼   ┼   ┼───┼   ┼───┼   ┼
│   │                   │           │       │       │       │   │
┼   ┼───┼───┼───┼───┼   ┼   ┼   ┼   ┼   ┼───┼───┼   ┼───┼   ┼   ┼
│                           │   │   │                       │   │
┼───┼───┼───┼───┼───┼   ┼───┼───┼───┼───┼───┼───┼───┼───┼───┼───┼