No worries mate: Many people have that problem, as it isn't explained outside of technical literature. In simple terms, one megabit is always 1/8 of one megabyte, and conversely, one megabite is eight megabits.
The only breaking of this rule occurs with the expressions
Mib, and
MiB are used, as this represents
Millions of bits, and
Millions of Bytes, respectively. Mega (as well as Peta, Giga, and Kilo) are always an expressions in powers of two
for computing; but not for
Telcom. In the computing industry, they represent the closes value in powers of two to 1000 (Kilo), 1,000,000 (Mega); 1,000,000,000 (GIga); and 1,000,000,000,000 (Peta).
In Telcom, the terms Megabit and MegaByte refer to
Millions, using standard Base-10 values, as Mib/MiB, which means
that the numbers differ from true values used in computing. One Megabit in computing is (1024^2) bits, and a MegaByte (1024^2) Bytes (i.e. 1024^2*8 bits).
(For reference, one
bit is the smallest value of information, one
Nibble is composed of four bits; one
Byte is composed of two Nibbles, or eight bits; one
Kilobit is 1024 bits and one
Kilobyte is 1024 bytes; one
Gigabit or Gigabyte is 1024^3 bits/Bytes; and one
Petabit or
Petabye is equal to 1024^4 bits/Bytes.)
In
telcom, one
Megabit is 1,000,000 bits, and this is (1000^2) bits; and
Megabytes is not generally used in the telcom industry. This can be misleading, as one megabit of
computer datum is not sent in a one megabit (telcom) transmission. One (binary, computer industry) megabit is 1,048,576 bits, which is
48,676 bits greater than the telcom megabit. One telcom Gigabit is 1-Billion (Base-10) bits, which when compared to a binary/computing Gigabit leave a 'staggering' difference of 73,741,824 bits (70.33Mb, or 8.8MB).
This is useful when doing calculations involving sending binary datum over a telcom line, as the values are different, for the same expressions of value.
That is why the computing terms
Mib and
MiB are used in some calculations, as these match the telcom Megabit and the telcom equivalent of MegaByte, for Mib and MiB are millions of bits, and Bytes, respectively,
using the same formulas as in telcom (e.g. 1000^2). Some operating shells, and data tools, will express datum values in this way, and it can be crucial to know the difference.
What really matters to you at present is that your internal ATA/100 bus is faster than FW400 protocol connections, and in fact, most FW400 drives used ATA/100 drives internally. It wasn't until around 2004/2005 that companies started using SATA mechanisms, and by that time, FW800 was more abundant.
Th rest of that, you can keep under you hat, until useful.
P.S. The term
baud, once synonymous in the industry to with data transfer rates over telcom lines, is similar to b/s, but not quite the same. For binary code, b/s is generally equal to baud, but in non-binary situations, baud can be extremely variable, and actually means
modulations per second. The telcom industry hasn't used the
baud term after the rise of the 'Megabit' connection, when they learnt that they could use, and abuse, the prefix 'Mega' as a form of
marketing spin. Everything was Mega-something for quite a while.
I expect we shall see the same thing again when fibre becomes available everywhere, and Gigabit connections become possible at an affordable rate.
One of the primary reasons that 'Megabit' is used instead of 'Megabyte', is because the numbers are eightfold larger, making the average consumer believe it is bigger/faster/better. People look at raw numbers, without realising the difference between Mb/MB/Mib/MiB/baud. Technically, the term mB is also a valid expression, meaning
microByte, so pay careful attention to the term being used, as a 100,000mB memory unit wouldn't hold a single bit of datum, but
a 125,000mB volume would hold one single bit.
