My knowledge of skillsofts, according to my memory, and double checked with the books in front of me is as follows:
You have to buy or create a Cluster Chip with enough memory to fit ALL of the Skillsofts that are going to be on it. You also have to ensure that there's enough memory for the Directory Program to be run simultaneously.
If you're using a Chipjack, you can buy and use an Expert Driver to receive a Task Pool usable for any skill in that jack (Skillsoft included).
If you're using a Datajack or Headware Memory and reading Knowsofts (or Linguasofts), you must have a Knowsoft Link.
If you are using Activesofts, you must have a full Skillwire system in you, but they can be read from a Chipjack, Datajack, or Headware Memory.
You can use one or all of the skills contained on the Cluster Chip at the exact same time, but each skill has to be activated (or deactivated) using a Free Action (though you can activate however many you want before a combat situation, which takes a negligible amount of time).
If you're using a Skillsoft Jukebox (usable in a Chipjack or Datajack only), you may have as many Skillsofts loaded as you have slots to fit them, but you can only have one activated at a time. Changing to another is a Free Action which involves a movement or verbal command if slotted into a Chipjack, or a Mental Command if in a Datajack.
Keep in mind that any skill read from a chip doesn't allow dice pools. No Combat Pool, Task Pool, Spell Pool, etc. The only exception is by using an Expert Driver.
I've never seen the abbreviation OCC, so I can't think off the top of my head what it stands for, sorry about that.