Why Learn to Program?

Computers are becoming more and more pervasive and powerful. Microcontrollers which are basically miniature computers are present in more and more everyday things from microwaves to automobiles.

Programming is fun! You get immediate feedback when you get something new working. This is why when I was a kid learning to program I loved working on graphics, and why as an adult I find it rewarding to work on user interfaces.

Learning to program also gives you a deeper understanding of how computer work and builds skills that are useful when using complicated softare for other purposes as well, not just writing it.

Programming and developing softare also requires a very different type of thought than many other things which makes it an interesting mental exercise. It is closest to mathematics just by being quite abstract in a similar way, but at the same time, most programming is still very different than math.

Computer Concepts

It's time to learn some basics about how computer hardware works to help you understand how to develop programs for them.


Every computer has memory which it uses to store information. Computers store information as groups of ones or zeroes which form binary numbers. Binary is a number system similar to the decimal system, but instead of being base 10 as in decimal numbers, binary numbers are base 2. That means that when they add to more than 1, you have to carry. It also means that the value of each digits place is twice the value of the place to its right, instead of ten times as much.

There are two basic types of computer memory, RAM and ROM.

RAM stands for random access memory, and this type of memory is temporary and changeable. RAM can be written to and read from repeatedly. The values are temporary and only last until they are overwritten or power is turned off and all the values are lost. Also the random access part refers to the ability to retrieve values from any position in the RAM at will as opposed to some other computer storage methods, like magnetic disks for example, which require seeking to the correct place.

ROM stands for read only memory. This type of memory can be read from in a way similar to RAM, but it has two important differences. It keeps its contents when power is turned off, and it cannot be written to except initially. Actually, this is not entirely true of some type of ROM which can be programmed(written) repeatedly, but it is a special, slow process still very different from that in RAM.


The part of the computer responsible for executing instructions from programs and making decisions and processing data is called the CPU which stands for central processing unit. In modern computers the CPU is a single microprocessor chip. Earlier computers had CPU's made of many discreet components instead of just a single chip. Today, many devices have microcontrollers in them which contain a microprocessor as well as built-in input/output peripherals, which we will discuss shortly.

The CPU, sometimes just called the processor, handles executing all the machine code instructions that make up a program. Each instruction tells the CPU to do a certain operation with certain operands. For example, an instruction might tell the CPU to load a value from a specific location in memory, and the next instruction might add that value to another.

These days computers have processors with multiple cores, which means they are basically multiple CPU's in the same physical package.

Input and Output

In order to be of any use, a computer must be able to input and output data. What is data?f Data is a collection of values or variables. Data has a similar but slightly different meaning than information. The difference is that information is something a person could consume or use to make a decision. Data is the raw values that must be processed, aggregated, or grouped to actually turn it into information. For example, all of the answers everyone in the United States provided during the most recent census would be data, but the statistics calculated from them such as the average household income would be information.

Common types of computer input/output peripherals include keyboards, mice, monitors, printers, wired or wireless network connectinos, sound hardware for recording or playback, and storage devices such as magnetic, optical or flash disks. We will talk about storage seperately in a moment. Many peripherals are connected over special buses such as USB, which stands for universal serial bus. USB is used for connecting devices such as keyboareds, mice, portable storage devices, phones, cameras, printers and digital headphones. Computer interface standards(buses) include other standards such as fireware(IEEE 1394), and SATA(serial ATA). There are also several standards for connecting monitors and displays such as DVI, HDMI, and DisplayPort.

Network adapters such as wired Ethernet adapters or wireless WiFi adapters are another important type of peripheral. These allow connection to local are networks (LANs) for sharing data with nearby computers as well as allowing computers to collect to the Internet over broadband connections or dedicated Internet connections typically found at businesses and universities.


Storage devices, which technically include the memory we already discussed also include slower types used for more permanant storage that can store greater amounts of data. Memory is known as primary storage. Secondary storage devices are not accessible directly by the CPU, but must be accessed via input/output channels.

The most common type of secondary storage for computers is the hard disk drive. Hard disks have rapidly rotating metal platters where tiny areas are magnetized to record the bits stored. Flash drives have more in common with ROM chips than hard disks. They are much faster than hard disks, but they have limitations on the number of time that they can be written to that limit their service life, whereas a hard disk drive will fail eventually, but eventually can often be a very long time with no fixed bound.

Optical discs provide another type of storage. CD-ROM's, DVD's and BluRay discs are all types of optical discs. The mechanisms are part of the drive, but the media where the data is stored is removable. This type of storage is very permanent provided it is not physically damaged, but it is significantly slower to wrote than magnetic storage. Many types of optical discs can also only be written once.

Data Units

We should define some units used for describing sizes of storage or data. * One bit is a single binary digit. * Eight bits form a byte.

Additionally, processors typically have a native size known as a word which is basically the amount of memory that can be retrieved in one memory access operation and stored in one register insdie the CPU. In typical modern computers this is either 32 or 64 bits.

Sometimes people use megabyte to mean 1,000,000 bytes and gigabyte to mean 1,000,000,000 bytes. This is usually because they are selling hard drives.

Units such as kilobits and megabits are typically used when describing network bandwidth speeds.