Thinking

src/docs/resources.md

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+# How BFFH thinks about "things":
+
+BFFH calls all things under it's (more or less existing and more or less total) control that users
+want to use or be in a specific state for specific reasons "resources". The right to use a resource
+or to change it's state is what BFFH calls a "claim".
+Resources can be "claimed" by a number n ∈ ℕ\{0} of people at the same time. How many exactly claims
+can be taken on a resource in parallel depends on the specifics of the resource. The (RGB) lighting
+in a space for example is something that can be claimed by any number of people; if it's dark
+outside everybody in the space will want the lights to be on. Who of all the people *allowed to*
+gets to control the colour of the lights is a social issue and not something that can be encoded
+into bffh easily.
+However, a precision mill or a 3D-Printer can not be easily used by two people at the same time
+without them stepping on each others toes. One of the two will be calling the shots, will be the one
+actually pressing the buttons that do the things. In BFFH terminology she is the user holding the
+claim.
+To establish terminology let's call a claim with n = 1 an "exclusive claim" and a claim for a
+resource that more than one user may claim a "shared claim".
+Resources can also hold claims themselves. For example a mill, vapour-phase-oven and PCB press may
+all three make used of an external cooling system which must turn on at the latest when any of these
+three machines start work and must not turn off until all three are back to cool and idle. The
+easiest way to represent this dependency is by having each (exclusive) claim on one of the three
+machines also encompass a shared claim on the cooling pump.
+Claims can be transferred between users. This serves two use-cases; first to transfer an exclusive
+claim without having to have a machine unowned in the meantime, as an exclusive handover. This is of
+course not so useful for shared claims.
+The second use-case applies to shared claims too however: Giving an user a claim they do not have
+the permission to take out themselves. This allows a supervisor to hand over control and claim of an
+usually restrictively permissioned resource — like a mill — to somebody else. Which most importantly
+stores the information that this somebody else is now using the machine and **not the supervisor**.
+
+Claims are ephemeral; you only hold an exclusive claim to a 3D-printer while it's printing your
+design, you only hold a shared claim to the spaces front door while you're inside — making them lock
+if you're the last one leaving.