Much of what is required to implement a triggering and data acquisition system for Hall D is technically feasable today. More ambitious projects in the field of High Energy Physics have been or will be implemented within the time frame for the proposed construction. Most details dealing with bandwidth and computing power are ones of scale (i.e. How many Level 3 farm nodes and tape drives will be necessary).
There are some issues that will require R&D on the collaboration's part. Firstly, prototyping of the FADC and TDC front-end electronics should be done, probably sooner then later. There are applications in the existing experimental halls that could benefit now from their design. Secondly, triggering without a tagger at high luminosities needs to be better understood. Information on the input, programming and fault tolerance of the GTP is need. More studies on detector response, rates, and occupancies under realistic physics conditions would be worthwhile. This would also provide information concering the processing and bandwidth requirements for the front-end as well as for the Level 3 farm.
For the DAQ backend, including the Level 3 farm and Online/DAQ management careful consideration should be used in implementing various strategies. Increased complexity can directly translate into increased costs (e.g. more CPUs or more manpower for software development). For the Level 3 farm one can look to more efficient network solutions such as parallel cluster processing. This is something that the SSI (Strategic Super-computing Initiative) is working on, and Hall D could take advantage of the resources. EPICS is probably overkill for slow controls and monitoring in Hall D. Perhaps one could use some EPICS tools at the network level (like cdev) to integrate various independent control systems. As an online strategy all Hall D control systems should be ``database-centric'' (including the DAQ). Of all the computing based technologies that are emerging today, Java should be embraced at some level in the development of the online system.