Why are memory addresses are represented using hexadecimal numbers?

Question

Whenever I see C programs that refer directly to a specific location on the memory (e.g. a memory barrier) it is done with hexadecimal numbers, also in windows when you get a segfualt it presents the memory being segfualted with a hexadecimal number.
For example: *(0x12DF)
I am wondering why memory addresses are represented using hexadecimal numbers?
Is there a special reason for that or is it just a convention?

Solution 1

Memory is often manipulated in terms of larger units, such as pages or segments, which tend to have sizes that are powers of 2. So if addresses are expressed in hex, it's much easier to read them as page+offset or similar constructs. Decimal is difficult because of that pesky factor of 5, and binary addresses are too long to be easily readable.

Solution 2

Its a much shorter way to represent what would otherwise be written in binary. It is also very nice and easy to convert hex to binary and back. Each 4 digits of binary corresponds to one digit of hex.

Solution 3

Convention and convenience: hex shows more clearly what relationship various pointers have to address segmenting. (For example, shared libraries are usually loaded on even hex boundaries, and the data segment likewise is on an even boundary.) DEC minicomputer convention actually preferred octal, but IBM's hex preference won out in practice.

(As for why this matters: what's easier to remember, 0xb73eb000 or 3074338816? It's the address of one of the shared objects in my current shell on jinx.)

Solution 4

It's the shortest, common number format, thus the numbers don't take up much place and everybody knows what they mean.

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Comments

[supercat]

It's worth noting that even in systems without any concept of virtual memory, hardware itself has for a very long time almost always divided memory into regions whose sizes and boundaries are either powers of two or small multiples thereof (e.g. a standard VIC-20 had 8-bit RAM from 0x0000-0x03FF and 0x1000-0x1FFF, and 4-bit RAM from 0x9400-0x97FF).

[glglgl]

Even Base32 is shorter, but the advantage of hex is that one digit is exactly half of an octet.

[8bittree]

The ease of conversion in hardware or software has nothing to do with it; it's trivial regardless of base. The use of hexadecimal (or octal) is for the ease of conversion by humans and pattern recognition by humans.

[ilansch]

Why do you mean "Decimal is difficult because of that pesky factor of 5" ? conversion between base 10 and base 2 ?