it hasn't meant anything else for a long time
Agreed, although odd things do still happen in the embedded world so we're encouraged not to assume it (or at least assert it!).
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Bits or Bytes?
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Posted 5 months ago #
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The 8-bit byte is a bit of a historical overhang: a byte is related to the size of a computer instruction (32 or 64 in most modern systems).
Cougar beat me to it. Byte = 8 bits, word = register size of the CPU ie 32 or 64 bit for modern CPUs.
Posted 5 months ago # -
1024 bytes is a kibibyte
Posted 5 months ago # -
mol, it really isn't. Read the wiki and the C++ FAQ I linked.
It's true that usually byte=8 bits, but it isn't/wasn't always the case. Historically there were architectures with 9-bit, 10-bit, 12-bit and 36-bit bytes (CDC, PDP-8, PDP-10).
We've pretty much settled on x86 inspired architectures now, which are all 8-bit or multiples thereof. So a byte is almost always 8 bits. But it's not correct to define a byte as being 8 bits.
Also in comms "a byte" may have extra start, stop and parity bits on it, as well as the 7 or 8-bits of data. Hence why they correctly use "octet" to refer to a group of 8-bits in comms specs.
Posted 5 months ago # -
GrahamS - you're really not doing your image any good....
Posted 5 months ago # -
Whateva
EDIT: So what defines the byte size for a system? The register size? If so, then what's a word?
Posted 5 months ago # -
who cares about bytes and words, it's all about nibbles and more importantly: meganibbles.
Posted 5 months ago # -
GrahamS - you're really not doing your image any good....
I have an image???
And it's one that can get worse????
Oh dear.
So what defines the byte size for a system?
I'm not entirely sure. I think it is basically the smallest unit that you can work with at the hardware/assembly level.
i.e. a modern 64-bit PC has a 64-bit word, but the x86 instruction set it uses contains instructions that operate on 8-bit bytes (e.g. LODSB, STOSB, CMPSB).
Posted 5 months ago # -
Any women reading this thread are just so hot right now...
Posted 5 months ago # -
Word.
Posted 5 months ago # -
Up.
Posted 5 months ago # -
What's a "women"?
Posted 5 months ago # -
I always though a word was twice as many bits as a byte. Hence in Windows typedefs WORD = 16 bits.
Posted 5 months ago # -
Nope, that's just a hangover from 16-bit versions of Windows.
Posted 5 months ago # -
I hate windows typedefs.
Posted 5 months ago # -
I hate window pelmets
Posted 5 months ago # -
small b is a bit, large B is a byte.
Not sure why they picked 4 bits to a byte, I think it was to do with the size of the MC instruction sets
Posted 5 months ago # -
The 8 bit byte was introduced by IBM with the 360 architecture.
FWIW.
Posted 5 months ago # -
who cares about bytes and words, it's all about nibbles and more importantly: meganibbles.
Nibbles are good, MegaNibbles even better... I'm not so hot on the middle ground though, the KilaNibble has always filled me with dread personally!
If so, then what's a word?
A Word is as long or as short as its needed to be. It can be 8 bits, or 16 bits, or it could be 1 bit, 39 bits, 427 bits, or however long it needs to be to represent a large enough number as is required. AFAIK, the 8, 16, 32 and 64 bits that we have become familiar with is purely because those are the convenient sizes that were determined by Microsoft/Apple/Intel/AMD etc for their computers and operating systems. You can of course represent any number with a word larger than is required, it will just begin with a lot of zeroes... For instance, if you wanted to represent the number 4 with a 64 bit word, it is just going to start with 61 zeroes which is kind of redundant...
Posted 5 months ago #
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