Ext. Hard disc

[jayantadak]

Hi,

What is the advantage of an Ext.Hard disc with an independent power supply.

Are there any downers if I go for an ext.hard disc which is USB powered.

Would there be any warranty issues if purchased from Dubai.

I m thinking of buying WD ext h.d. 500 gb.

Kindly let me know

Regards
JAYANT ADAK

 

[alokbharti]

please search the forum.. there are many similar threads..

http://www.hifivision.com/home-theater-pc-htpc-media-pc/10020-external-storage-help.html

http://www.hifivision.com/blu-ray-dvd-players-dvd-hard-disk-recorders/9949-ext-hard-disc.html

 

[sam9s]

There is no advantage as such of an independent power supply ext HDD except maybe its cost over USB one......

 

[venkatcr]

USB works across an internal hub that delivers power to all the devices connected as well as transfers data to and from the devices.

A bus powered hub is initialized as one unit load and can go to max unit loads. In other words each device connected to the bus has to draw one unit load and even a single device can draw a max of the unit load specified.

The USB 1.x and 2.0 provide a 5V supply across a single wire. As per specifications the bus will supply a max of 5.25V and not less than 4.75 volts. A unit load is defined as 100mA that can go to a max of 500mA. Devices are defined as low-powered and high-powered. Low powered devices have to draw a minimum of 1 unit or 100mA. High powered units cannot draw more than 500mA.

A 500GB hard disk operates at 5V direct current and draws 500mA during read/write operations and 400mA when idle. This is cutting it very close and you may not be able to use a 500GB drive by supplying power through the USB. In most situtions, unless you have multiple USB buses inside the computer and you can connect the drive through multiple buses, you will get a 'power surge' warning on the computer.

It is always better to use an external power supply for large drive such as 500GB and above. Even a 150GB drive may need you to connect to two USB ports.

Cheers

 

[sam9s]

I have a 160GB/320GB portable USB HDD, and my friend has a 500GB USB drive, all works just fine with a single USB. Infact Todays even 1TB HDD does not need two USB ports to get power.......I presume that was with older drive or older boards with anemic USB ports, where a Y connector type USB cable was provided to draw power with 2 USB ports. Current Gen high capacity USB drive does not have such limitation.....

Check this out...

My Passport Essential SE 1 TB USB 2.0 Hard Drives ( WDBABM0010BBK )

 

[spirovious]

. This is cutting it very close and you may not be able to use a 500GB drive by supplying power through the USB.
It is always better to use an external power supply for large drive such as 500GB and above. Even a 150GB drive may need you to connect to two USB ports.

Cheers

I use 500BG WD ext2.5mm without any failure.I have used with Hemant & Bizare's Lapy without prob during Mumbai meet.

 

[santhosh]

I have a 160GB/320GB portable USB HDD, and my friend has a 500GB USB drive, all works just fine with a single USB. Infact Todays even 1TB HDD does not need two USB ports to get power.......I presume that was with older drive or older boards with anemic USB ports, where a Y connector type USB cable was provided to draw power with 2 USB ports. Current Gen high capacity USB drive does not have such limitation.....

I use 500BG WD ext2.5mm without any failure.I have used with Hemant & Bizare's Lapy without prob during Mumbai meet.

IMO, I think USB 1.1 required a Y type USB connector - one USB does power, the other does data. With USB 2.0, this is no longer required.

 

[deba]

I have an old 160gb maxtor drive which draws power from 2 usb ports but the new seagate 500gb external draws power from only one usb port.

I like usb powered over ac powered because its compact and hassle free.