Thread: Speed of optical stuff + Bottleneck?

Hey all,

I'm a newb here forumwise, have just one question for anyone that would want to take it up if you know the answer right off the bat.

I know that different components on a computer transfer data at different speeds, (my guess anyway).

but for optical parts like CD lens, etc. does the transfer between the disc and the drive go at SOL (speed of light), but there is a bottleneck between the hard drive and CDROM on the ide channel, i'm asking for example?

i've always assumed that the cdrom drive is reading fairly fast, but the bottleneck for overall speed is between the CDROM drive and the hard drive, even between IDE channels.

just a heads up question.

Also I would like to know if there is another bottleneck from the IDE channel to another part of the computer when transfering files in between or on just one drive.

Thanks for your considering!

:-D

Tom A.


I don't care if you're mac/pc user either since this applies to both...certainly I'll take this from an expert.

Okay. Yes the laser is omitted and reflects back at the speed of light, but the distance is negligable.

There are other things to take into account such as BUS speed, speed of memory, bandwidths etc.

Okay, basically put. Electricity travels at the speed of light. however performance restictions come itno effect with transistors which need to switch from a state of being "open" or "closed" it is the time that it takes the transistors to do this which creates a decrease in speed.

You can create more "bandwidth" for the data by increasing the number of transistors performing the work load.

There are other factors such as how much oxygen is contained within the copper wire etc, but these account for data relability more than speed.

Suprisingly enough though, unless you play computer games or rendering graphics etc the speed of your PC shouldnt be an issue as most business machines dont need that much power. The biggest bottleneck in speed as far as a buisness machine goes is probably the human and at the rate at which they can type. Luckily I have been blessed with a 90wpm ability, but not are all so lucky. I have worked with one person in my life before who had to actually look around the keyboard for the key the wanted to press. It was really laughable.

Originally Posted by leohopkins

Okay. Yes the laser is omitted and reflects back at the speed of light, but the distance is negligable.

There are other things to take into account such as BUS speed, speed of memory, bandwidths etc.

Okay, basically put. Electricity travels at the speed of light. however performance restictions come itno effect with transistors which need to switch from a state of being "open" or "closed" it is the time that it takes the transistors to do this which creates a decrease in speed.

You can create more "bandwidth" for the data by increasing the number of transistors performing the work load.

There are other factors such as how much oxygen is contained within the copper wire etc, but these account for data relability more than speed.

Suprisingly enough though, unless you play computer games or rendering graphics etc the speed of your PC shouldnt be an issue as most business machines dont need that much power. The biggest bottleneck in speed as far as a buisness machine goes is probably the human and at the rate at which they can type. Luckily I have been blessed with a 90wpm ability, but not are all so lucky. I have worked with one person in my life before who had to actually look around the keyboard for the key the wanted to press. It was really laughable.

That's a rather gallant attempt at answering but....

Assuming you mean 'c' as the speed of light, neither electricity nor the laser light in your CD travels at this speed (you need to add in a propogation factor - for glass that's about 0.68).

The maximum data transfer rate to/from a CD player ie the number of bits passing the head per second, is a function of the focal capabilities of the laser (which must resolve down to 1/2 bit at least). The speed of light has no bearing whatsoever on this. Data is 'buffered' in great chunks as it is read, the host then reads this 'at it's leisure'.

WiFi also travels at the speed of light, but that doesn't mean anything when it comes to how fast data transfers.

Beyond that I can't really explain it because it makes some sense to me, but not enough to tell someone else it.

Thanks guys for explaining! plus was quick response.

if anything, helped a good amount!

Cheers
Tom

Other things to consider


Hello digiplaya,
I am by far no expert but I would also like to add; that currently IMO (and probably most others) the major hardware bottlenecks in computers are by far your hard drive followed by a computers ram. The hard-drive is a major bottleneck almost purely because of its mechanical components.

To be able to understand how bandwidth works I like to use this old explanation I heard. Essentially imagine a water pipe that is 1 cm thick. You can send water through it as fast as you like but you’re still limited to the total volume of that pipe at any given moment. If bandwidth increases it’s like increasing the width of the pipe and therefore increasing the volume of water that can be pumped through it at any given moment regardless of speed. Although bandwidth is measured in bits, bytes, megabytes etc per unit of time.

However (just for the record) in my understanding the current most severe bottlenecks are no longer related directly to your hardware (as most hardware components are incredibly fast today) but rather to how information is logically organized ready for your CPU, GPU or the like to be processed and how well software is written to be able to utilize this available information.

Most of the time your CPU is in a ‘wait state’ waiting for information to be sent to it, this is directly related to the speed of your components but also largely depended on a number of techniques used to get instructions “prepared” for your CPU or like to be processed. A detailed explanation of all this is beyond what I could write but you may want to google any one of these search terms. CPU cache, Instruction prefetch, Instruction set utilization and Front side bus. These are all just some of the factors that affect a computers ‘speed’.