[Reglor]

The datajack plus from Kill Code states that it can run a number of programs equal to its rating but how many programs can it hold?  Does it only hold those programs and can it hold any number of programs?

I'm wondering if I can get a Fuchi Cyber-N deck and using the datajack plus to supplement the number of programs I can run.

[Hobbes]

Matrix Storage in 5e in not tracked.  It's presumed you either d/l the program from the Matrix as needed or have it stored on your Commlink, RCC, Cyberdeck, shoelaces or N.E.R.P.S. can or whatever.  If you've bought the program, you have access to it.

[Xenon]

KC p. 25 Programs
Programs must be purchased individually, but there is no limit to the number of programs you can have in storage. The number of programs that can run at once can be found in each device’s description, although no single program can be running more than once at a time.

[RickDeckard]

DJ+ comes in 3 ratings, 1, 2 and 3. It can run a number of programs equal to its rating, and they are in addition to the programs already running on your cyberdeck. Actively running, not in storage.