Using the COPY, SWITCH, DELETE, and RENAME commands, you can manipulate the archive and the volumes as described in the KerboScript page.
But before you do that, it's useful to know how kOS manages the archive and the volumes, and what they mean. This sidebar page is meant to do that.
What's a File
There is one file per program. You can use the words "file" and "program" interchangeably in your thinking for the most part. Files are stored in volumes and there can be more than one file in a volume provided there's enough room. Volumes have small storage and there's no way to span a file across two volumes, so the limit to the size of a volume is also effectively a limit to the size of a program.
Storage of a "file" behind the scenes.
In the Archive: If a file is stored on the volume called "Archive" (or volume number zero to put it another way), then behind the scenes it's really stored as an actual file on your computer (Ships/Script as of version 0.15.5) Each program is a simple text file you can edit with any text editor, and your edits will be seen immediately by KOS the next time it tries running that program from the archive volume. In any other volume besides Archive: If a file is stored on any volume other than archive, then behind the scenes it's stored actually inside the saved game's persistence file in the section for the KOS part on the vessel.
What's a Volume
A Volume is a small unit of disk storage that contains a single hard drive with very limited storage capacity. It can store more than one program on it. To simulate the sense that this game takes place at the dawn of the space race with 1960's and 1970's technology, the storage capacity of a volume is very limited. It can only store 10,000 bytes of program text - less than 10 Kb The byte count of a program is just the count of the characters in the source code text. Writing programs with short cryptic variable names instead of long descriptive ones does save space. This is old school programming, where squeezing every byte out matters.
Multiple Volumes on one Vessel
Each kOS CX-4181 Scriptable Control System part contains one such volume inside it. Therefore to send a craft into space with more storage capacity than 10,000 bytes requires putting multiple CX-4181 Scriptable Control System parts on the craft.
If you have multiple CX-4181 parts on the same craft, they are assumed to be networked together on the same system, and capable of reading each other's hard drives. Their disk drives each have a different Volume, and by default they are simply numbered 1,2,3, ... unless you rename them with the RENAME command.
For example, if you have two CX-4181's on the same craft, called 1 and 2, with volumes on them called 1 and 2, respectively, it is possible for CPU 1 to run code stored on volume 2 by just having CPU number 1 issue the command SWITCH TO 2.
Naming multiple volumes on one vessel
It's important to note that if you have multiple volumes on the same vessel, the numbering conventions for the volumes will differ on different CPUs. The same volume which was called '2' when one CPU was looking at it might instead be called '1' when a different CPU is looking at it. Each CPU thinks of its OWN volume as number '1'.
Therefore using the RENAME command on the volumes is useful when dealing with multiple CX-4181's on the same vessel, so they all will refer to the volumes using the same names.
Archive
The "archive" is a special volume that behaves much like any other volume but with the following exceptions:
- It is globally the same even across save games. The archive represents the large bank of disk storage back at mission control's mainframe, rather than the storage on an indivdual craft. While "Volume 1" on one vessel might be a different disk than "Volume 1" on another vessel, there is only volume called "archive" in the entire solar system. Also, there's only one "archive" across all saved universes. If you play a new campaign from scratch, your archive in that new game will still have all the files in it from your previous saved game. This is because behid the scenes it's stored in the plugin's directory, not the save game directory.
- It is infinitely large. Unlike the other volumes, the archive volume does not have a byte limit. This is because the mainframe back at home base can store a lot more than the special drives sent on the vessels - so much so that it may as well be infinite by comparison.
- Files saved there do not revert when you "revert flight". When you revert a flight, you are going back to a previous saved state of the game, and therefore any disk data on the vessels themselves also reverts to what it was at the time of the saved game. Because the archive is saved outside the normal game save, changes made there are retained even when reverting a flight.
- It's not always reachable if you are out in space, unless you have antennae. Once a vessel is more than 100,000 meters away from mission control, by default it cannot access the files on the archive. Commands such as SWITCH TO ___ , and COPY ___ FROM ___ will fail to work when trying to access the archive volume while out of range. This can be changed by putting antennae on the vessel. With enough activated antennae is it becomes possible to reach the archive drive from farther away. Using this method it is possible to alter the software stored on a vessel after launch.
- Files in Archive are editable with a text editor directly. Files in the Archive are stored on your computer in the subdirectory: ~/Ships/Script (as of v0.15.5) You can pull them up in a text editor of your choice and edit them directly, and the KOS Mod will see those changes in its archive immediately. Files stored in other volumes, on the other hand, are stored inside the vessel's data in the persistence file of the saved game and are quite a bit bit harder to edit there. Editing the files in the Archive directory is allowed and in fact is an officially accepted way to use the plugin. Editing the section in a persistence file, on the other hand, is a bad idea and probably constitutes a form of cheating similar to any other edit of the persistence file.