Bits vs Bytes

[butterfly]

I am busy developing a guide, a small excerpt from it below, which I think might be useful knowledge to a few forumites I have referenced quite a few articles, safe to say that the below article is correct. I welcome any feedback regarding information that is not accurate. Just think, when Vodacom has upgraded their networks to full 7.2 functionality, we can theoretically achieve close to 1 MB download speeds

A bit is the smallest unit of information that can be stored or manipulated on a computer; it consists of either zero or one. It could also, instead be described as false/true, off/on, no/yes, and so on. We can also call a bit a binary digit, especially when working with the 0 or 1 values.

A bit is not just the smallest unit of information, but for sake of discussion it can be said that a bit is also the largest unit of information a computer can manipulate. The bits are bunched together so the computer uses several bits at the same time, such as for calculating numbers. There are eight bits in a bunch, a bunch is called a byte.

So, if 8 bits is a byte, 16 bits is 2 bytes, 32 bits is 4 bytes, 64 bits is 8 bytes,... 8192 bits is 1024 bytes.

Computer information is based on two units consisting of digital 0’s and 1’s, 2 to the 10th power equates to the number 1,024, thus, 1024 bytes equals 1 kilobyte (1 KB). Alternatively put: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, etc.

Based on these calculations, we can simplify the below table.
• 1024 bytes = 1 kilobyte (1KB)
• 1048576 byte = 1024 KB = 1 megabyte (1 MB)
• 1073741824 bytes = 1024 MB = 1 gigabyte (1 GB)
• 1099511627776 bytes = 1024 GB = 1 terabyte (1 TB)

While we are on the subject, lets cover the Internet, connection versus download speeds, based on the above.

For example, you have a 384 Kb ADSL connection from your ISP, 384 Kb or 384 kilobits ÷ 8 = 48 KB or 48 kilobytes. Therefore, your download speeds on a 384 Kb, can theoretically achieve a maximum download speed of 48 KB/s on a good, stable connection.

Thus:
• 512 Kb ADSL connection = 64 KB/s
• 1 Mb ADSL connection = 128 KB/s
• 2 Mb ADSL connection = 256 KB/s
• 3.6 Mb 3G connection = 460 KB/s
• 4 Mb ADSL connection = 512 KB/s
• 7.2 Mb 3G connection = 920 KB/s (Nearly 1 MB per second !!)

 

[Pyro]

Quite important to mention, according to SI standard, Kb refers to Kilobit, which is actually 10^3 = 1000 bits. In computers this K is so often used as 10^3 or 2^10.

Not too important, as long as you don't allways expect 1024 divisions.

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Also, while 8b=1B, all your download bandwidth isn't used for actual data. ADSL specifically uses ATM encapsulations IIRC, that gives some overheads. All connections are subject to TCP/IP overheads though, so you won't see all that data.

Wireless connections are also quite variable. You effectively share much of that potential data with everybody on the same antenna. In the US they were quite disgusted with their new pimping 7.2Mb connections when they went from an effective 1.5Mb to 1.6Mb in tests.

I've got exceptionally bad signal I guess. I could only download about 250MB from steam over HSDPA on my laptop. That's 568Kb/s effective or 71KB/s. Significantly less than the maximum of 460KB/s.

 

[butterfly]

Thanx Pyro, I value your input, I will incorporate the first line in to my guide accordingly.

 

[P0is3nIvy]

...or if you want to get you hands dirty, a bit is voltage, either +5volts (0) or -5volts (1).
Your modulator-demodulator is responsible for the conversion from digital (0 and 1) to analogue (-5 to +5 volts) and vice versa.

 

[butterfly]

Thanx for your input as well, P0is3nIvy, I value it. Its nice knowing how to look at situations from every angle.