Star considers infrastructures to be both essential collaboration as well as inherently limiting the degree to which collaboration is possible. This is ascertainable by looking at the way she thinks about infrastructure’s following characteristics:
_ Embeddedness. Infrastructure is sunk into, inside of, other structures, social arrangements and technologies;
_ Transparency. Infrastructure is transparent to use, in the sense that it does not have to be reinvented each time or assembled for each task, but invisibly supports those tasks;
_ Reach or scope. This may be either spatial or temporal—infrastructure has reach beyond a single event or one-site practice;
_ Learned as part of membership. The taken-for-grantedness of artifacts and organizational arrangements is a sine qua non of membership in a community of practice (Lave and Wenger 1991; Star 1996). Strangers and outsiders encounter infrastructure as a target object to be learned about. New participants acquire a naturalized familiarity with its objects as they become members;
_ Links with conventions of practice. Infrastructure both shapes and is shaped by the conventions of a community of practice, for example, the ways that cycles of day–night work are affected by and affect electrical power rates and needs. Generations of typists have learned the QWERTY keyboard; its limitations are inherited by the computer keyboard and then by the design of today’s computer furniture (Becker 1988);
_ Embodiment of standards. Modified by scope and often by conflicting conventions, infrastructure takes on transparency by plugging into other infrastructures and tools in a standardized fashion.
_ Built on an installed base. Infrastructure does not grow de novo; it wrestles with the inertia of the installed base and inherits strengths and limitations from that base. Optical fibers run along old railroad lines; new systems are designed for backward-compatibility; and failing to account for these constraints may be fatal or distorting to new development processes.
_ Becomes visible upon breakdown. The normally invisible quality of working infrastructure becomes visible when it breaks: the server is down, the bridge washes out, there is a power blackout. Even when there are back-up mechanisms or procedures, their existence further highlights the now-visible infrastructure.
_ Is fixed in modular increments, not all at once or globally. Because infrastructure is big, layered, and complex, and because it means different things locally, it is never changed from above. Changes take time and negotiation and adjustment with other aspects of the systems involved. (Star 2010, 611)
