You bought a hard drive, the size of it was given in gigabytes. Nevertheless, these units were widely used among tech people and consumers alike. There was no official standardization regarding kilobytes, megabytes, gigabytes, etc. In summary: if the size of data units is a power of 2, such as 8 = 2³, many internal calculations a computer needs to do are much simpler than they would be otherwise. Just observe that the result was trivially computed by shifting digits to the left. Don’t try to understand the encoding yet. It is just shifting the input by three bits to the left. In binary arithmetic, powers of 2 like 8 = 2³ are equally convenient. Binary arithmetic is based on powers of 2. That’s true in our decimal system - a numeric system based on powers of 10.Ĭomputers do binary arithmetic internally. Let’s take a step back for a second: for us, multiplying or dividing by powers of 10 is trivial by just appending zeros or shifting the decimal point, right? I’ll try and hint at underlying practical concerns. Why is a byte 8 bits, and not 10?Ī mixture of historical and practical reasons.

When you get there, try coming back and look at it. Therefore most information - barring compression mechanisms - is encoded in bytes as basic units, not bits.īy the way, at the end of the article you’ll be able to get back to the 40 bits above, and figure out what they mean. You always read or write one whole byte at a time, not individual bits. You can request to read or write data in one of those bytes by specifying an offset from the starting point. Bytes are relevant as a unit, because - generally speaking - they are the smallest addressable units of memory. One such piece of data - a zero or one - is called a bit. Hard drives and computer memory just stores ones and zeros.

Read binary file details