Look, I like interesting fiddly details in my games – if this retro-future involves optical disks the size of coasters, great, sign me up, that's how we do things here. But usually things get really fiddly and crunchy really quickly, with precise counts for things that probably don't matter all that much in the global scheme of things. As such, I'd like to jot down some general notes on the modern age of data storage, particularly the range of capacities a similarly sized object can hold, and then offer a solution for those who just want to know if they can fit all of their programs on one disk or chip or whatever crunchy media you're using.
So, let's start with the two terms we're going to be using to describe data without using direct numbers - basically, stand-in variables. First is the quad. Used in Star Trek, Uplink, and various other media, a quad is a consistent amount of storage capacity. Typically described in kiloquads, megaquads, gigaquads, and possibly teraquads.
The second term we're going to be using is the qubit. The qubit is essentially the amount of information that a program requires in order to be stored. If we set this consistently, then if one program takes up ten qubits, then five copies of that program would take up fifty qubits.
And the final question: how many qubits are in a quad? If you need to make your storage capacity only large enough to hold a single program on a plug-n-play ROM chip, this number may be very low; if you need the galaxy to fit on a single flash drive, it needs to be very high.
So, what sizes of storage media might exist?
Speck Chip: This microscopic chip is the storage media used for nanobots, and is roughly 1/10th of a millimeter.
Flake Chip: This tiny pinhead sized chip is likely the sort used to hold instructions for microbots. Roughly one millimeter in diameter.
Microchip: A square chip roughly 3mm by 3mm.
Datatab: A small chip the size of a micro SD card.
Datachip: A larger chip the size of a standard SD card.
Thumbdrive: A small device that plugs into a standard UDT port.
Chipslot: A large old-school cartridge-sized chip bank.