Okay, little one, imagine you have a lot of books that you need to store in a bookshelf. But instead of books, we have little parts that help our computer remember things, called memory modules.
A single in-line memory module (SIMM) is like a little bookshelf with memory modules stacked one on top of the other. It's called a "single" module because it only has one row of memory modules stacked together, like one shelf of a bookshelf.
SIMMs were used in older computers to store information temporarily, like when you're playing a game or working on a project. They were smaller and took up less space than the older memory modules, helping to make computers more efficient.
But now, computers have newer and fancier memory modules that can store more information and help them run faster. So, SIMMs aren't used as much anymore.
Does that make sense, little one?