Where does fence collide?

A person who buys stolen property from thieves and resells it, acting as the commercial link between theft and the ordinary market. Klockars's 1974 book The Professional Fence gave the first close academic portrait of this role, following one long-running dealer and showing how the trade operated and how he kept a public front as a legitimate businessman; Steffensmeier's 1986 The Fence: In the Shadow of Two Worlds extended the account with a second case. Here the word names a human occupation in the underground economy, studied through the people and transactions involved, not a control step inside a computer or a boundary that pens molecules on a cell surface.[1][2]

Unit

One receiver of stolen goods, or a single transaction between a thief and the dealer

Recovery means

Not applicable

Measured by

Studied through ethnographic interviews, career histories, and records of stolen-goods transactions and networks

An instruction a processor runs to force an ordering on memory reads and writes, so that accesses issued before it finish, and become visible to other processors, before accesses issued after it. The ordering requirement it serves was formalized by Lamport in 1979 in How to Make a Multiprocessor Computer That Correctly Executes Multiprocess Programs, which defined sequential consistency, the guarantee a fence helps restore on hardware that otherwise reorders memory access for speed; Adve and Gharachorloo's 1996 tutorial Shared Memory Consistency Models laid out how fence, also called memory barrier, operations work across relaxed models. In this field the word names a control step inside a computer, counted in machine instructions, not a person who trades stolen goods or a physical boundary inside a living cell.[3][4]

Unit

A single fence operation placed between memory accesses in a program

Recovery means

Not applicable

Measured by

Reasoned about in formal consistency models and observed through program behavior and the performance cost it adds on real hardware

A boundary formed by the mesh of protein filaments just beneath the cell membrane that briefly confines the sideways movement of molecules in the membrane, so a protein or lipid hops between small compartments rather than drifting freely across the whole surface. Kusumi, Sako, and Yamamoto proposed this membrane-skeleton fence model in 1993 in Confined Lateral Diffusion of Membrane Receptors as Studied by Single Particle Tracking, following single receptors that were held within these corrals; Kusumi and colleagues' 2005 review Paradigm Shift of the Plasma Membrane Concept generalized the picture. Here the word names a physical partition inside living tissue, measured in nanometres and in milliseconds of confinement, not a dealer in stolen goods or an instruction that orders a computer's memory.[5][6]

Unit

One membrane compartment bounded by cytoskeletal fences, tens to hundreds of nanometres across

Recovery means

A confined molecule eventually hops the fence into a neighbouring compartment

Measured by

Measured by single-particle and single-molecule tracking of diffusion, yielding hop rates and compartment sizes