penguin1

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1. Some external drives require a extra power cord. Some can get enough just from a single usb 2.0 port. May i ask what is the maximum power output of a usb2.0 port?

2. eSATA has been very successful. Do you think there will there be USB3.0 in the future? Is it even in the making? and do u think ps2 will be obsolete one day?
 

itneal2277

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USB provides a voltage of approximately 5 volt (4.75 - 5.25 volts to be exact) and allows a current up to 500 mA. You can check here for more info on USB. I have not heard anything on a new standard though. Yes, I do think USB will replace p/s 2 as well as the parallel and serial interface. The only thing I've ever seen parallel used fore is printers and USB has taken over that market. Serial used to be widely used for mice but not anymore. Serial still needs to stick around for terminal services to configure some routers and switches.
 

adamhb

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There are also a lot of legacy instrumentation devices and controllers that require serial (RS-232 and RS-485) so it will definatly still be around for a few years yet.
 

JonathanDeane

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any idea why most keyboards still use ps/2 interface when usb2.0 transfer speed is higher?

I know its probably just me but PS/2 just feels faster like its more connected to the hardware or something. I like my PS/2 mouse better then most of the USB mice I have used (some where pretty good though) I guess I just like seeing the USB ports free for other more cool things :)
 

ZOldDude

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eSATA has been very successful.

Has it?
I don't know anyone who uses it,has a MB that suports it nor any shop in Los Angeles that deals with it.

In the endgame it is like the non-certifide interface SATA-2 and no HD made for home or office use can even use all the bandwith of a ATA line as it is already.

Z
 

itneal2277

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I know eSATA is hard to come by but there are lots of motherboards with eSATA connectors on them. As far as drives that support them I have seen many either but when I did a search many came up. Here is a link.
 

pengwin

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any idea why most keyboards still use ps/2 interface when usb2.0 transfer speed is higher?

I know its probably just me but PS/2 just feels faster like its more connected to the hardware or something. I like my PS/2 mouse better then most of the USB mice I have used (some where pretty good though) I guess I just like seeing the USB ports free for other more cool things :)


Mice = USB
Keyboards = PS/2

thats how i see it the mouse has to be USB cuz usually needs power. also USB mice are generally better.
 

maury73

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USB power magament is more complicated than written in theese posts.
The standard current limit is 100mA per port. A device can request up to 500mA in steps of 100mA if all other devices connected to the same root controller allow it.
In all mobos each root controller manages 2 ports, so you will be able to draw 500mA from one port if the other of the same group is connected to a self powered device.

PS/2 is still common because is much simplier to implement and, despite its lower bandwidth, it has lower latency. It also permits to draw up to 500mA without any strange protocol handshake, so it is used for bar code readers and similar devices.

Serial and parallel ports are very used in industry and instrumentation: PLC, automation systems, instruments and similar devices all require serial RS232 connection, because it's much reliable, simplier and doesn't require the extra overhead of an USB controller.