Terminology & Conventions

The following terminology and conventions are used throughout SpiNNer’s scripts and code.

Cabinets, Frames and Boards

When discussing SpiNNaker systems, it is assumed that the system is comprised of SpiNN-5 boards arranged in standard 19” cabinets and frames like so:

          2             1                0
Cabinet --+-------------+----------------+
          |             |                |
+-------------+  +-------------+  +-------------+    Frame
|             |  |             |  |             |      |
| +---------+ |  | +---------+ |  | +---------+ |      |
| | : : : : | |  | | : : : : | |  | | : : : : |--------+ 0
| | : : : : | |  | | : : : : | |  | | : : : : | |      |
| +---------+ |  | +---------+ |  | +---------+ |      |
| | : : : : | |  | | : : : : | |  | | : : : : |--------+ 1
| | : : : : | |  | | : : : : | |  | | : : : : | |      |
| +---------+ |  | +---------+ |  | +---------+ |      |
| | : : : : | |  | | : : : : | |  | | : : : : |--------+ 2
| | : : : : | |  | | : : : : | |  | | : : : : | |      |
| +---------+ |  | +---------+ |  | +---------+ |      |
| | : : : : | |  | | : : : : | |  | | : : : : |--------+ 3
| | : : : : | |  | | : : : : | |  | | : : : : | |
| +---------+ |  | +|-|-|-|-|+ |  | +---------+ |
|             |  |  | | | | |  |  |             |
+-------------+  +--|-|-|-|-|--+  +-------------+
                    | | | | |
         Board -----+-+-+-+-+
                    4 3 2 1 0

A convention used throughout SpiNNer is to refer to individual boards by their position expressed in the form of (cabinet, frame, board) triples.

Triads and Boards

When describing large systems, their size is referred to either as a number of SpiNN-5 boards or in terms of their width/height in triads. A triad is a group of three SpiNN-5 boards connected like so:

 ___
/   \___
\___/   \
/   \___/
\___/

This pattern is repeated horizontally:

 ___     ___     ___     ___
/   \___/   \___/   \___/   \___
\___/   \___/   \___/   \___/   \
/   \___/   \___/   \___/   \___/
\___/   \___/   \___/   \___/

And then vertically:

 ___     ___     ___     ___
/   \___/   \___/   \___/   \___
\___/   \___/   \___/   \___/   \
/   \___/   \___/   \___/   \___/
\___/   \___/   \___/   \___/   \___
    \___/   \___/   \___/   \___/   \
    /   \___/   \___/   \___/   \___/
    \___/   \___/   \___/   \___/

Thus, in this example, we have a 4x2 triad, or 24 board system.

When specifying systems just in terms of numbers of boards, the squarest-possible arrangement of triads with that number of boards is assumed (preferring landscape arrangements when a square arrangement is not possible).

Physical Dimensions

All real-world physical dimensions are given in meters.

Physical coordinates are supplied in 3D space with the axes going from left-to-right, top-to-bottom and front-to-back for X, Y and Z respectively.

   _  Z
   /|
  /
 /
o-------> X
|
|
|
V
Y

Folding

For definitions of the terms used to describe the folding process (e.g. shear, slice and uncrinkling), please refer to “Bringing the Hexagonal Torus Topology into the Real-World” by Jonathan Heathcote et. al. which is available on request and is expected to be published at some future point.