For example, if I looked at a door and wanted to remember what that door was for, I could "see" a vast 2 or 3 dimensional array of hundreds of doors that I had seen before, arranged so that similar doors were near each other, and then I was aware of some kind of focusing in on the region of door-space where doors similar to the target door resided, and then I was aware of some kind of comparison of each of the doors in that region serially with the door I was looking at to find a match, and then the data for the best match was made available to my normal consciousness.
During another part of that trip I was aware of audio processing. I'd hear someone talking and first hear it as unintelligible sound, then I'd be aware of the sounds being broken down into separate sound units, and then recognized as English words, and then the relationships between the words being recognized, and then I'd become aware of the meaning of what I'd heard.
I also had a time during that trip where I was watching visual processing. I'd be aware of how my mind was noticing things in the scene I was looking at, recognizing objects and remembering what they were, and combining that to build an understanding of the scene.
Now I have no way of knowing how much of this was just hallucinations shaped by my knowledge of computers, and how much really was the LSD actually letting me observe consciously mental processes that normally operate as black boxes to the conscious.
It's too bad research using LSD was greatly curtailed when the drug was banned. My suspicion is that what I perceived on that trip was a mix of reality and hallucinations driven by my computer knowledge. With enough experimentation, with people with different backgrounds observing and reporting, we could probably get some real insights into what is really going on in there.