EPROMs

The word EPROM is an abbreviation for Erasable Programmable Read-Only Memory.  In short, it is a memory chip for a computer that stores information when the power has been turned off.  When the EPROM has been programmed, the only way of it being erased is by exposing it to extreme UV light.  The EPROM is stored in an opaque package, this is so that it cannot be erased once programmed.  You can see the EPROM through the top of it because of the transparent fused quarts window.  This also allows the UV light in when it is time for the chip to be erased.

Obsolete electronics are electronics, components and semiconductors that are hard to find or that are not being made anymore.  Many websites etc offer help to try and find those electronics that you cannot.  It can sometimes be quite costly however there are many distributors who specialise in finding the items and getting them for you.