Final answer:
The external SRAM on the DE2-115 board has a storage capacity of 512KB.
Step-by-step explanation:
The DE2-115 board is an FPGA development board designed by Terasic. It includes a 512KB external SRAM chip. The dimensions of the external SRAM on the DE2-115 board refer to its storage capacity, not its physical size. The external SRAM is used to provide additional memory for the FPGA applications.