Can someone explain to me the bandwidth mathematics. I read in some post that "... get speed of 30 KBps i.e. 240 KBps". What is its meaning? Why divide by 8?

This topic has been discussed quite a few times earlier... but i'll still explain it to you

There is a big difference between KB and kb

KB means Kilo Byte
kb means Kilo Bit

8 bits makes a byte.

When reffering to bandwidth the term 'kbps' is always used instead of KB/s.

If you have a 256 kbps line that would mean that you would get a transfer rate of 256kbps divided by 8 which equals 32KB/s.

Similarly,
512 kbps divided by 8 equals 64KB/s and
1 mbps => 1024 kbps divided by 8 equals 128 KB/s

Hope that clears it up for you.

Thanks !

LOL, "Speed Mathematics" is a nice name!

As Anoop said, there is a big difference between bits and bytes (exactly 8 times, to be precise ). Uppercase 'B' refers to a byte and lowercase 'b' means a bit.

Code:

1 byte = 8 bits

, which can also be written as

Code:

1 B = 8 b

. Thus, "1 MB" means "1 megabyte" while "1 mb" means "1 millibit", which is a difference of 8 million times!

Also, nitpickingly, I must say that at least for the SI units, the prefix for kilo- is the lowercase letter 'k', not uppercase 'K'. Like kilometre is "km", kilogram is "kg", etc. But then again, some people have adopted the convention that uppercase 'K', in computing, refers to the "computer kilo", namely 1024.

Knowing what kilo- and mega- mean when you're talking of computers is really a VERY confusing issue. To quote from physics.nist.gov/cuu/U...inary.html :

Quote:

Once upon a time, computer professionals noticed that 2^10 was very nearly equal to 1000 and started using the SI prefix "kilo-" to mean 1024. That worked well enough for a decade or two because everybody who talked kilobytes knew that the term implied 1024 bytes. But, almost overnight a much more numerous "everybody" bought computers, and the trade computer professionals needed to talk to physicists and engineers and even to ordinary people, most of whom know that a kilometer is 1000 meters and a kilogram is 1000 grams. Then data storage for gigabytes, and even terabytes, became practical, and the storage devices were not constructed on binary trees, which meant that, for many practical purposes, binary arithmetic was less convenient than decimal arithmetic. The result is that today nobody knows what a megabyte is. When discussing computer memory, most manufacturers use megabyte to mean 2^20 = 1 048 576 bytes, but the manufacturers of computer storage devices usually use the term to mean 1 000 000 bytes. Some designers of local area networks have used megabit per second to mean 1 048 576 bit/s, but all telecommunications engineers use it to mean 10^6 bit/s. And if two definitions of the megabyte are not enough, a third megabyte of 1 024 000 bytes is the megabyte used to format the familiar 90 mm (3 1/2 inch), "1.44 MB" diskette. The confusion is real, as is the potential for incompatibility in standards and in implemented systems.

.

The same page ( physics.nist.gov/cuu/U...inary.html ) also mentions a system to avoid the confusion that was adopted in 1998, but the system (using names like "kibibyte" or "KiB" to mean "1024 bytes", and using "kilobyte" to mean "1000 bytes"), despite being adopted by the IEC, doesn't seem to have become popular yet.

I (and probably most us?) thought that 'K' always stood for 1024 and 'M' always for 1024 x 1024 in computer parlance. Thanks for the detailed clarification.