I'm not asking how information is sent to the motherboard and then to the monitor (I just made that up, by the way). I'm asking, how it is that words, pictures, and programs, etc, are on little bits of metal and plastic discs?

The little pieces of metal are actually circuits conducting electricity. They are basically organized into gates that are like electrical on/off switches. On means a one bit and off means a zero bit. Amass a large nest of a variety of gates and you can represent a complex variety of data. All other hardware exists to store or manipulate the data, or to convert it to human-sensible phenomena (sound, light, shock).

It's an extremely complicated question, but the short answer would be that each alpha numeric character has a code attached to it. That code translates it into a series of 1s and 0s (which means that either a spot in the memory is in the on or off possition). The computer keeps track of all of these and designates a space in memory, and on the disks, for each. It keeps track of the order, so can reassemble it in order.

These are stored in memory, because each bit of data either has an electrical charge (a 1) or does not (a 0). It's stored on disk drives by having a magnetic charge at each space to represent the same.

Bad engineer joke:

Every little chip inside has little pockets of trapped smoke. Smoke is what makes the computer work. Smoke eats electricity, so you have to feed it electricity to make it work, but if you feed it to much the smoke will get too strong and it will escape from the chip and your computer won't work anymore.

Bad engineer joke:
What do you mean, 'joke'? That's how it works! The smoke is magical, hence the term 'magic smoke', and the phrase, 'it runs on magic smoke. if it escapes, it stops working'.

I'm not asking how information is sent to the motherboard and then to the monitor (I just made that up, by the way). I'm asking, how it is that words, pictures, and programs, etc, are on little bits of metal and plastic discs?

Magnetism.

That's the shortest answer I can give you. (The others in this thread aren't wrong, they're just different parts of the elephant. You saying "exactly".... well, that begs for either a huge answer or a smart-assed answer.)

If you want to know the long answer, join the navy and tell them you want to be a DS. There, you will learn more than you ever thought possible to know about how computers really work. (But since the navy decided to stop making DSes, and I'm the last one (no joke), I don't know if the program I went through still exists. It was pretty fascinating. Didn't tell me how to do my job, but it was definitely fascinating. If I still had my books and stuff, I might try to teach it.)

There are several layers of abstraction between "words, pictures, and programs" and silicon transistors, which is what most circuits boil down to.

For programs the layers can be viewed ruffly as:
1) The application level of what is a program, that most computer users are familiar with and is generally required to effectively use a computer. This is Greek to non computer users.
2) The operating system. All but the most primitive applications have to go through the operating system API to do anything important, and are restricted by operating system permission settings. The operating system handles the allocation of memory and other resources, including the inner workings of virtual memmory/swap.
3) Device drivers. Each component in the computer, except a few very basic components, act as little computers by themselves. They need a protocol for interacting with the OS in order to serve their function. The drivers define this protocol.
4) Chip level. Any non-trivial operating requires a microchip. Non-trivial means anything more complex than if there is a current flowing use it to power this LED. Microchips deal with primitive logic signals that can be treated as boolean equations. In microchips signals are seen as high and low voltage, which can be viewed as 1s and 0s.
5) Microchips are made up of Electronic gates. Gates work like boolean primitives -- the addition, multiplication, and negation of boolean math.
6) Gates are made up of transistors. There are only two types of transistors, but they make up all logic gates.

More levels should probably be added between levels 1 and 4. Each of these levels of abstraction represents an answer to the successive question of "How does that work?", untill finally, at level 7, by my count the answer boils down to physics (as it always does).

Data is a little simpler, in a way. Words and pictures are represented each by a sequence of numbers that make up a file, and by a different set of operating system specific numbers explaining a few properties of the file, such as the filename and the size. It is then up to individual programs to map these two sequences of numbers to useful representations such as pictures and words.
But the programs that decode these files are of course subject to the above layers of abstraction. They and the operating system are involved in making sure this decoding process works and that the data gets sent ultimately through the right transistors at the right time.

That's really the best way to describe it, via layers of abstraction.

The above post could be viewed as an index of all the other posts in this thread - all the other posts have so far been details about one layer or another. (or more than one)

There are only two types of transistors, but they make up all logic gates.Zuh?! :confused:

There's like a zillion types of transistors. Or are you just refering to CMOS using nMOS and pMOS transistors?

I think he means NPN and PNP, but those aren't necessarily relevant to the discussion. (Also, there are more types, but those are the two that they're built on.)

Unless he meant logic gates, AND and OR, which make up all logic systems. (But there's also NOT. XOR can be made with an arrangement of the others.) IIRC, these three gates can be made with 3 transistors each, which includes the support circuits to keep the input voltages and currents equal to the output voltages and currents (so it's not as trivial as, say, tying the outputs of two transistors together). XOR requires about a dozen gates.

I think he means NPN and PNP, but those aren't necessarily relevant to the discussion. (Also, there are more types, but those are the two that they're built on.)No way! Practically all digital logic devices are FET based today. BJT logic is generally used for specialized applications.

Unless he meant logic gates, AND and OR, which make up all logic systems. (But there's also NOT. XOR can be made with an arrangement of the others.) IIRC, these three gates can be made with 3 transistors each, which includes the support circuits to keep the input voltages and currents equal to the output voltages and currents (so it's not as trivial as, say, tying the outputs of two transistors together). XOR requires about a dozen gates.First off, AND and OR do not make up all digital logic systems. With AND and OR alone you cannot make a NOT gate, which makes such a device of very limited utility. If you were to use discreet gates to make a logic system, you would want to use NOR or NAND, because either alone can make all other gates. I know that many ICs will pick one of the two and stick with it throughout the entire design to save on the complexity of having many different arrangements of transistors on their chip. I'm not sure if this how it is done in modern VLSI designs (I generally am only interested in what chips can do, not the nitty gritty bits of their construction), but they certainly aren't just AND and OR gates.

Unless he meant logic gates, AND and OR, which make up all logic systems.

As Perfy said, these can't build everything you need. There are 16 different algebraic functions for a system with 2 inputs. NAND and NOR are the pillars of logic however, as combinations of either can build any of those 16 operators, and therefore absolutely any logical combination you want.

As Perfy said, these can't build everything you need. There are 16 different algebraic functions for a system with 2 inputs. NAND and NOR are the pillars of logic however, as combinations of them can build any of those 16 operators, and therefore absolutely any logical combination you want.

Actually, IIRC, "NOR" OR "NAND" are each SEPARATELY sufficient to build all the other operators.
You need just one of them.

I remember building all the other gates out of a NAND gate on an assignment back in school once.

Fun times.

Actually, IIRC, "NOR" OR "NAND" are each SEPARATELY sufficient to build all the other operators.
You need just one of them.

Indeed, that's what I meant. What a terribly illogical way to write that.

I think he means NPN and PNP, but those aren't necessarily relevant to the discussion. (Also, there are more types, but those are the two that they're built on.)

Yeah, this, but I'm sure you guys know more about them then I do.

Computers work by having small pixies that smoke electricity living inside them. [EDIT: Their children, pixels, make the images on your monitor - by sewing bits of bytes together]

Computers are clasified into the number of bits they have. Open up your computer, it has lots of bits inside.

Computer viruses are caused by PCs being too close together.

Computers work on binary numbers (1s and 0s). This is why it is important to have untangled cables. The 0s, being round, can roll down the cables. If your cables have kinks in them, the 1s, being elongated, get stuck and cause blockage.

A better question would be how don't computers work.