Use the Search function and type 'harp packets'. This will bring up the conversations on this subject. Look for ones from about 2 months ago and look for posts by Tom Hopkins. He has some very detailed info. Here's one of his posts:
I’ve gone back and compiled some of my previous posts on this subject:
The glissando harp instruments map notes to the white keys of the keyboard. They are designed to be used with MIDI data packets to control the specific mapping of the keyboard. These packets control switches that change mapping assignments and emulate the pedal positions of the harp. This approach was introduced in Gary\'s GigaHarp library (and originally programmed for Giga by Dave Govett). The GPO library includes a MIDI data file that contains a library of MIDI packets covering a wide range of scale and chord types in all keys. I strongly recommend that the library of MIDI data packets be organized into an easy-to-access group as part of the user\'s sequencer default song file. I\'ve organized mine by key (C, C#, D, D#, E, etc.) and symmetrical scales (whole tone, diminished, augmented). Each key is placed on a separate sequencer track with all variations for a given key laid out horizontally on that track. The library tracks are always left muted because the packets are there for copying purposes only. If your sequencer allows it, place them in a folder for clarity. The packets are easy to use - just copy the packet for a particular chord/scale to a secondary track set to the same MIDI channel as the harp. Place each packet slightly in advance of the position of the desired scale or chord change. So, there are two tracks that share the same MIDI channel: the harp part is recorded to the harp track and the MIDI packets are placed as needed in the second track. Glissandi played from the keyboard will change chord/scale automatically at the packet position when the sequencer is in play/record. The white keys of the keyboard can be “strummed” to achieve realistic glissandi.
The glissando harps/MIDI packets emulate pedal positions and, in the process, add another dimension to the sound of glissandos beyond the chromatic harps. This is related to the way the harp works when creating chords and certain scales. There is a characteristic duplication of pitches on different strings depending upon harp pedal positions. For example an ascending A major chord arpeggio isn’t just the notes A, C#, E, A, C#, E, etc. when strummed with a finger. It’s more like A, A, C#, C#, E, E, E, A, A, C#, C#, E, E, E, etc. and each duplicated pitch varies a little in character because it is produced on a different string. That’s one of the main things that gives the harp its special sound on arpeggios. The glissando harps/MIDI packets emulate this effect giving the combination a very authentic sound. Now, you could try to duplicate this effect with the chromatic harps by using the same pattern of repeated pitches but you would not have the added benefit of differing character between strings that is supplied by the glissando harps.
Of course, all note data, packet choices, and packet positions can be edited after the fact if desired. Here is a list of the included scales and chord types:
1. All major scales
2. A, B, C#, E, F# major chords (the only ones that can be constructed with all triadic elements).
3. All major 7 chords
4. All minor/minor7 chords (available type depends on construction restrictions)
5. All dominant 7 chords
6. All dominant 9 chords
7. All altered dominant chords (but with variations based on construction restrictions)
8. All diminished chords
9. All diminished 7 chords
10. All pentatonic scales
11. All lydian scales
12. Both whole tone scales
13. All augmented chords