help needed about the concept of bit

[Badar]

A bit is simply a binary digit that can be 0 or 1.
2^n gives the possible number of combinations for n bits.

But how will i justify the statement that a 32-bit processors means 2^32=4294967296 calculations per second and a 64-bit processor means 2^64=18446744073709551616 calculations per sec.

How will i justify the exponential increase in calculations per second due to simply increase in number of bits as i just now 2^n gives poosible arrangments or combinations of bits.

 

[jbeng]

But how will i justify the statement that a 32-bit processors means 2^32=4294967296 calculations per second and a 64-bit processor means 2^64=18446744073709551616 calculations per sec.

Personally, I don't even see how you could make that statement. 2^32 simply means that a 32-bit word has 4294967296 unique combinations. There is no implication as to the number of calculations per second which can occur.
Jeff

 

[Badar]

Personally, I don't even see how you could make that statement. 2^32 simply means that a 32-bit word has 4294967296 unique combinations. There is no implication as to the number of calculations per second which can occur.
Jeff

I am not sure about my statement too but i think i happened to read it somewhere authenticated but again i m not very much sure.

But let me ask in some other way.
Say Landsat satellite has 8-bit radiometric resolution in a specific band, it means that our electronic sensor can diffenetiate 2^8=256 brightness values in this band.

Then how 8 bit relates 256 brightness values.

 

[Badar]

I m very much confused about this concept of bit and now want to make sure about my statement of 32 bit processor and 64 bit processor too.
Any help is highly appreciated.

 

[yngndrw]

The lowest value is 0.

The highest value is 11111111b.

The column headings for these bits are as follows:
128 64 32 16 8 4 2 1
1 1 1 1 1 1 1 1

128*1 + 64*1 + 32*1 + 16*1 + 8*1 + 4*1 + 2*1 + 1*1 = 255

0 -> 255 is 256 possible combinations.

Is that what you're asking ?? - As you add more bits, the most significant column heading (On the left) is double the previous, hence why it goes up exponentially.

 

[Badar]

The lowest value is 0.

The highest value is 11111111b.

The column headings for these bits are as follows:
128 64 32 16 8 4 2 1
1 1 1 1 1 1 1 1

128*1 + 64*1 + 32*1 + 16*1 + 8*1 + 4*1 + 2*1 + 1*1 = 255

0 -> 255 is 256 possible combinations.

Is that what you're asking ?? - As you add more bits, the most significant column heading (On the left) is double the previous, hence why it goes up exponentially.

hmm i think i had ask the same think.
now can somebody plz tell me about the differnece of 32 bit processor and o 64 bit one.
does 32 bit processor simply means calculation of 32 bits per unit time or it means 2^32 calculations per unit time

 

[Nigel Goodwin]

does 32 bit processor simply means calculation of 32 bits per unit time or it means 2^32 calculations per unit time

It's got no relation to time or speed of calculations, it's simply how many bits it can deal with at one time. A 32 bit processor can take two 32 bit numbers and add then together in a single instruction, for a 64 bit addition it will take multiple instructions, and multiple registers. A 64 bit processor will do the same addition in one operation.

I'll give you a nice easy 'example':

Say you run a company that sells barrels of wine, and you have various size trucks for delivering them. You have an 8 barrel truck, and a 32 barrel truck.

If I order 32 barrels from you, you can either send the 32 truck once, or the eight truck 4 times. However, if I order 33 barrels, it then becomes two trips for the large truck, or only 5 for the small truck.

If I only order 8 barrels it's obviously much more efficient to send the 8 barrel truck!.

Bear in mind that the larger truck costs much more money to run.

That's really what you're talking about, more bits tends to be intriniscally faster - but can be much less efficient as well. Bear in mind text and most other data is only 8 bit!.

 

[ClydeCrashKop]

Nigel, can I get an invitation to your next party?

 

[Nigel Goodwin]

Nigel, can I get an invitation to your next party?

Never said it was good wine!

 

[Hero999]

It also depends on what you want to do with the data, if all you're doing is copying it from one memory location to another then 64-bit is good even if it's just text. A 64-bit processor can copy eight characters with one instruction whilst an 8-bit processor can only copy one.

 

[Nigel Goodwin]

As long as they are sequential data bytes!.

To a certain degree more bits are better, but it is a more wasteful system - to the extent that many processors over the years have had different varients - such as 32 bit processors available with either 32, 16, or only 8 bit data buses.

 

[theinfamousbob]

Never said it was good wine!

Depends on how long the party runs.


As for the processor bits/bus bits, why was it even thought to put a 32 bit processor on a 16 bit bus? The only thing I can think of is to make upgrading a possibility, but sacrificing the full speed of the new processor.

 

[Nigel Goodwin]

Depends on how long the party runs.

Considering how far you have to come, you turn up and I'll pour alcohol down your throat until you're pissed!

As for the processor bits/bus bits, why was it even thought to put a 32 bit processor on a 16 bit bus? The only thing I can think of is to make upgrading a possibility, but sacrificing the full speed of the new processor.

Simply cost, memory was VERY expensive, and in similar terms still is - using 8 bit data memory (or 16 bit) on a 32 bit processor saved a LOT of money.