If you rude people would bother to read the rules or "how to post" threads, you wouldn't double post (one wonder if you fart in a new church before finding out it's frowned upon). The 32-, 64-bit designation is based on the width of the data bus. The size of an integer would likely be 32 for the first, and 64 for the second, because that's the largest size the machine can handle with a single read. There is no requirement that it be specified in this way, it might be defined as smaller, but one tends to define the integer as the largest single value the machine can fetch in one operation. A byte is always size 1, per the standard. A byte is not necessarily 8 bits, however.