I know that in general only one device can transmit over the bus at once, but if they are all memory devices, can they act as one? I have four 256x8 chips, which I think means that I have 256 cells which can store 8 bits (1 byte). So how would I express the total memory? 256 cells * 4 = 1024 cells, but I am not sure whether or not the answer is 1024x8 or 1024x32. I am leaning towards 1024x8 because I don't think that more than one device can trasmit over the data bus at once, but I am not certain now that I know that all the devices are memory devices.
The four 256x8 devices can be arranged as 1024x8, 512x16, and 256x32 - if your bus width is flexible. If you can only have an 8 bit bus then no, only 1 device can write to the 8 bit bus at a time and you have a 1024x8 arrangement.