White | Action Performed | Distribution | Process | |
| Budgeted | Reference | Reference | |
Step |
| Requirements | (Locality) |
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3 | LRF3: Raster Image Processing |
| DRF3: | PRF3: |
| WSB3: reads the buffer queue address list and |
| Printer | Page_RIP |
| begins reading the data blocks. As the block |
| Control Unit |
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| are processed, one or more page bitmaps are |
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| rendered to memory and stored in available |
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| page bitmap buffers. |
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4 | LRF4: Raster Image Processing |
| DRF4: | PRF4: |
| WSB4: indicates the input data block is |
| Printer | Input_data |
| available for reuse after the block is read and |
| Control Unit | _buff_mgt |
| processed. |
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The header material for the Build Page operation provides context for elaborating the JRT. This JRT decomposition allocates the functionality of the single
The Action Performed column captures both the logical entity performing the action and the logical step performed. In this example, two logical entities, I/O Services and Raster Image Processing, collaborate to print a page.
NFRs are allocated to the logical
The last two columns provide the distribution and process references. In this example the Printer Control Unit locality and Data_rec process must perform the operation of receiving a block and putting it into memory within the same 10 millisecond budget.
The JRT maintains context, captures the logical and distribution decomposition, and provides for the allocation of nonfunctional requirements. With the JRT in place, (or, as noted before, developing it in parallel), it is useful to represent the content in SysML as a coupled set of sequence diagrams showing the same flow in the different viewpoints. Figure
Chapter 5. Understanding distribution of responsibility | 89 |
