Finding the systems nobody mentions in the kick off meeting
Inventory work is fieldwork. The list you are given at the start is the list of systems with budget lines, which is not the same as the list of systems the plant depends on. The rest are found by walking, by watching what people open during a shift, by asking what they do when a particular screen is down, and by looking at what is actually connected to the plant network rather than what the network diagram says should be.
Certain categories are reliably missing. Machine embedded software supplied with equipment, where the vendor holds the only copy of the configuration. Departmental tools bought on a card and never registered. Spreadsheets that have become interfaces, which are systems in every sense that matters except that nobody calls them one. Remote access left in place by a supplier after a commissioning visit. Each of these is a dependency and each needs an owner recorded against it.
The register itself should be small enough that somebody can realistically keep it current. Name, purpose, version, owner, support arrangement, criticality, what it depends on and what depends on it. A register with dozens of fields per system is accurate for about a month and then quietly rots. We would rather have a handful of fields that are still true a year later, with a review trigger attached to change control, to procurement and to any new equipment arriving with software inside it.
- Discovery by walking the plant and observing use, not only by collecting a stated list
- Machine embedded software recorded, including who holds the configuration
- Spreadsheet interfaces treated as systems, with owners and a dependency entry
- Supplier remote access identified and either removed or brought under control
- A short register designed to stay current, with a defined review trigger