bit and Bytes 101

[lostsoul62]

Everyone knows that there are 8 bits to a Byte. It's been 30 years since I went to school for this so here it goes. A modem like dial up there is 10 bits to every Byte sent and I guess it is that way sending data over the Internet now a days. On a hard drive you have to have a bit between every Byte so I'm thinking is a total of 10 bits for every Byte or did they change something in the last 30 years?

 

[GeneO]

Hard drives drives use 8b/10b encoding. So your 3 Gb/s hard drive can, in principle, do 300 MB/s tops.

The encoding provides better power and transmission characteristics (google up 8b/10b encoding). Your PCI Express uses this encoding too.

The Internet doesn't use 8b/10b encoding - some of the hardware that carries Internet data may use a 8b/10b encoding, like a Gigabit Ethernet, but it is not required or part of Ip or the Internet.

 

[brianzion]

here is collection of Data Measurement Charts
LINK >>>> Data Measurement Chart

USB 3 >>> USB 3.0 SuperSpeed will be 10 times faster than the 480Mbps limit of the 2.0 spec. The example Intel likes to give out when talking about the new speed is that transferring a 27GB HD movie to your future media player will only take 70 seconds with USB 3.0, while it would take 15 minutes or more with 2.0. Keep in mind that you’re only going to be able to take advantage of this speed if your portable storage device can write data that quickly. Solid state devices will benefit most from the speed boost, while magnetic hard disks will be limited by their RPM and corresponding read/write speeds. Also, new Mass Storage Device drivers will have to be developed for Windows to take advantage of the spec.

 

[lostsoul62]

The Internet doesn't use 8b/10b encoding - some of the hardware that carries Internet data may use a 8b/10b encoding, like a Gigabit Ethernet, but it is not required or part of Ip or the Internet.[/QUOTE]

Well out of over a dozen answers your the only one who understands my question. I've tried to find out with no luck but on a hard drive and because of the encoding would there be a total of 10 bits for every Byte on the hard drive? Why wouldn't the Internet have this same encoding with 10 total bits for every Byte. I went to school for 2 years to become a computer tech and that was what we were taught with all the techie stuff why. So I'm just asking a question that you really need a formal education to understand but it has been 30 years and I'm just wondering.

 

[RayFinkle]

From your last post, it seems like you are asking 2 separate questions.

"The Internet" is comprised of many different entities, and all sorts of equipment, connections, and protocols. The only standard you could really attribute to the Internet as a whole is TCP/IP, which is layer 3 and up. 8b/10b encoding happens at a lower layer, and would only really be relevant between directly connected hosts.

About the hard drive side of things......You say there are 10bits for every byte on the hard drive. I thought the 10b part was only on the interface, not actually stored on the hard drive, ie, the platters......??? I am pretty sure about this, but I could be wrong.... Don't forget, 8b/10b is used at the Link Layer (layer 2).

Trust me, these days, formal educations aren't what they used to be. I learned a LOT more just playing around with stuff, and reading on my own, than what my "formal" education gave me.

I am curious. What is the real question you are trying to answer? Please keep in mind, you are talking about mutiple things here. What an interface does at the lower layers in order to communicate with the other side of the connection, is different from what is happening at higher layers, ie, actual user data, packets, etc.....and at the lower (physical) layer, too, for that matter.

You might do good to study up on the OSI 7 layer model.

 

[GeneO]

From your last post, it seems like you are asking 2 separate questions.

"The Internet" is comprised of many different entities, and all sorts of equipment, connections, and protocols. The only standard you could really attribute to the Internet as a whole is TCP/IP, which is layer 3 and up. 8b/10b encoding happens at a lower layer, and would only really be relevant between directly connected hosts.

About the hard drive side of things......You say there are 10bits for every byte on the hard drive. I thought the 10b part was only on the interface, not actually stored on the hard drive, ie, the platters......??? I am pretty sure about this, but I could be wrong.... Don't forget, 8b/10b is used at the Link Layer (layer 2).

Trust me, these days, formal educations aren't what they used to be. I learned a LOT more just playing around with stuff, and reading on my own, than what my "formal" education gave me.

I am curious. What is the real question you are trying to answer? Please keep in mind, you are talking about mutiple things here. What an interface does at the lower layers in order to communicate with the other side of the connection, is different from what is happening at higher layers, ie, actual user data, packets, etc.....and at the lower (physical) layer, too, for that matter.

You might do good to study up on the OSI 7 layer model.

No you are not wrong. The 8b/10b is for the low level transfer protocol, not the bits stored on the disk. The bits stored on the disk have their own overhead, though that is transparent to the end user. Quoted capacity in storage is real available capacity for the user, quoted link speeds for disk drive technology ( e.g. 3Gb/s or 6Gb/s) need to be corrected for 8b/10b encoding, but even then you are usually limited by the hard disk technology, not the link speed.

And yes, what is the question