Apparently these memory devices were never intended for long-term storage.
Bus loading limited the design to 2 external memory devices.
This is due to the way memory devices are fabricated.
When you take a picture or a video, it is saved on a memory device.
There will be just one solid state memory device in the computer.
This bus required a program counter and a data address register in each memory device.
A memory device is built from a grid of such "cells".
In any case, I'll bet this large glass is a memory device.
A number of new memory devices have been proposed to address these shortcomings.
Many such field/probe pairs are used to make up a memory device.