Mapping securities

Hash function design for low-latency FPGA security mapping

This hard digital design question tests whether you understand the trade-offs between dynamic and static hash table implementations in high-frequency trading systems. Tick-to-trade latency depends critically on how quickly an incoming security identifier can be mapped to a fixed memory location in an FPGA, and hash collisions introduce unacceptable delay.

The question probes your knowledge of hash function families and when each is appropriate. Specifically, it asks you to identify the class of hash function that exploits prior knowledge of the data set—in this case, the known set of securities that will ever be traded—to eliminate collisions entirely, while remaining static (unchangeable at runtime). This approach trades off offline computation and design time against zero collision probability and guaranteed O(1) lookup latency in the data path.

• Hash function families and their collision properties
• Static vs. dynamic hash table design
• Memory addressing and latency in FPGA implementations
• Trade-offs between precomputation and runtime flexibility