Core memory speeds

With core memory the general rule was the smaller the donut the faster the cycle. The real limiting factors have always been the physical size of the array of cores. The plane, a mat of wires with little teeny-tiny ferrite donuts at each intersection, looks electrically like a lot of inductors all strung in series. This is a good configuration for a low pass filter that we are going to put a very fast pulse through. The bottom line of all this is that even fast core memory tends have around 0.490us write cycle times. Read cycles are always twice the write cycle times. This means you need to read the core memory specs carefully. Be sure that you see the both read and write cycle times. If you can only find one it will most likely be the write cycle time.