Dynamic Random Access Memory (DRAM) runs off of a grid of transistors and capacitors that are used to store bit information. When an element of DRAM is to be accessed selectors find the appropriate row and column to connect to. The ability to switch from one element of the array to a completely unrelated element of choice leads this to the random access portion of it’s name. A significant disadvantage of the system is the requirement of precise voltage control and limitations of access to the elements during refresh periods (In DRAM capacitors lose charge over time). This is nowhere near the limitations of delay line memory (DLM, not official abbreviation). DLM takes electrical impulses and converts them to some mechanical function, usually waves, that pass through an object over time and are converted back to electrical impulses at the end. If it is necessary to store the signals longer they are simply rerouted back into the medium. Because the signals are in a specific order as a mechanical wave they may only be read as a sequence of data that must finish traveling through the medium before any process can be used to split it apart. This may be significantly slower than DRAM, however, it was the only method available for a long time. Another disadvantage is that depending on the chosen medium DLM had to be secured by precise environmental controls and featured additional calculations to maintain as well as read. Today DRAM is used in various electrical devices that store information for a temporary period of time, but only while powered. A perfect example of this is the computer you are most likely reading this posting from. Manufacturing of DRAM is a very long and complicated process I will not be covering today. Bye bye.
