The PIC was invented many years ago, but since then was acquired by Microchip, a Silicon Valley company, who improved it significantly and made it the popular microcontroller it is today. The process behind developing a PIC for a particular project is as follows:
First a program is written on any word processor (Notepad works well), or dedicated development enviroment (such as PIC Press), using a specific language for the PIC. This is very similar to machine code, and the ideas behind it are very similar to the Z80. Another advantage over the Z80 language is that rather than consisting of a stream of numbers, which (and I speak from experience) can be very confusing to the user, the PIC's program language consists of acronyms and the jumps are to labelled program segments rather than to a particular line number. Assigning words to all the commands, and indeed the different registers of the chip makes the whole process a lot more visual and understandable, which is the direction in which microcontrollers are moving these days - the Z80 and its contemporaries are out of date.
After writing the program, it can be assembled using a piece of software from Microchip (MPASM), this points out mistakes to the user. NOTE : MPASM only points out the mistakes in the syntax (grammar) of the program and not semantic errors (ones concerning what the program actually does). Once the program has been successfully assembled, it can be simulated to see if it will work. All the software for this is visual and easy to understand, the user isn't simply looking through a complicated string of numbers, but a program made up almost entirely of words which can be easily followed as the program is stepped through.
Once satisfied that the program is correct, the user can feed the program into a blank PIC - preferably a UV- or electrically-erasable PIC. The chip can be placed in the circuit which is then tested, if further adjustments are necessary these can be made, and the PIC reprogrammed. When everything is perfected, a one-time programmable PIC may be programmed, to be put in the final circuit.
The PIC in its previous forms has already taken off in a major way in industry and at the university level. Simple 8-pin devices are ideal for schools, combining ease of use with versatility. Two of the 8 pins are used up for the power supply, but the other 6 can be used as input/output pins, or as pins with other preset functions. You are presented with a wide range of choices, making it suitable for many projects. It has its own on-board clock timer, so no external source is required (though one can be used if desired).