DRAM modules are collections of dynamic random access memory (DRAM) chips assembled on circuit boards

Programmable automation controller (PAC) modules are add-on devices that perform a specific control function in PAC systems

Programmable automation controllers (PAC) are compact industrial controllers used in applications such as data acquisition and control, machine vision control, and process control.

Memory modules are computer chips used to add memory to a computer

Static random access memory (SRAM) modules are a collection of SRAM chips assembled on a circuit board.

Programmable automation controller (PAC) systems consist of PAC modules, each of which performs a specific function.

Static random access memory (SRAM) chips do not need to be refreshed like DRAM chips.