Concurrency structure is concerned with logical concurrency. The components of this structure are units of concurrency that ultimately are refined to processes and threads. Properties relevant to this structure include priority, preemptability, and execution time. This structure is key in understanding performance and is also important for reliability and security. Properties relevant to this structure include availability, capacity, and bandwidth.
Developmental structure is concerned with files and directories.
This structure is important for managing and ensuring administrative control of the system as it grows and is fleshed out, including the division of work into teams and configuration management. One reason why architects use multiple views simultaneously is that each view exposes some information and hides other information. Thus, for example, when reasoning about the functions of the system and the modifiability of the system, distribution issues are not the primary concern. The code structure abstracts away distribution issues. On the other hand, when reasoning about performance, distribution is primary and the function of the system becomes secondary, so a concurrency structure is more appropriate.