Although this comment is voted into oblivion, and I know the tone wasn't great, the poster is actually making an interesting point in one sense - the fact that

Although this comment is voted into oblivion, and I know the tone wasn't great, the poster is actually making an interesting point in one sense - the fact that technology often comes back around another time in a new form. For example, along the lines of IBMs IMS, I also recall the MUMPS system and language [1] and I'd be interested to know if the inventors of TileDB were familiar with the history of sparse array interfaces to databases or not, if it influenced their design in any way or it was rediscovered. Regarding MUMPS: "The MUMPS language provides a hierarchical database made up of persistent sparse arrays, which is implicitly "opened" for every MUMPS application. All variable names prefixed with the caret character ("^") use permanent (instead of RAM) storage, will maintain their values after the application exits, and will be visible to (and modifiable by) other running applications. Variables using this shared and permanent storage are called Globals in MUMPS, because the scoping of these variables is "globally available" to all jobs on the system. The more recent and more common use of the name "global variables" in other languages is a more limited scoping of names, coming from the fact that unscoped variables are "globally" available to any programs running in the same process, but not shared among multiple processes. The MUMPS Storage mode (i.e. Globals stored as persistent sparse arrays), gives the MUMPS database the characteristics of a document-oriented database." [1] https://en.wikipedia.org/wiki/MUMPS https://en.wikipedia.org/wiki/MUMPS