Re: [tlug] External DVD drive

[jep200404@example.com]

On Wed, 09 Jan 2013 09:32:00 +0900, Darren Cook <darren@example.com> wrote:

> The DVD drive in my notebook is broken, so I was going to buy an
> external one (*). 

> This is for Ubuntu; I have an eSATA port, but I think using USB would
> make it more useful; e.g. if I get some tablet in the future.

> Any recommendations or things to watch out for?

Pay attention to power supply and power consumption. 

USB hosts are not required to grant more than 100 mA to each 
USB port. When laptops are running on battery, it is common 
for them to deny requests from USB devices that request more 
than 100 mA. Optical drives need much power. They often have 
two USB connectors. The extra connector is just to help suck 
power, which is completely against the USB spec. It is not 
unusual for each plug to pull more than the max 500 mA per 
the USB spec. There are USB hosts that really can not output 
enough power for a USB optical drive. 
An example of such is a Raspberry Pi. 

It would be nice to have a USB optical drive, powered by the 
USB host, that plays by the rules. I don't know of any. 
Fortunately, many USB hosts don't enforce the power 
consumption limits. 

It might be prudent to shop for a USB optical drive 
that can get its power from either its USB host or from 
an external power supply (through a power jack). 
They exist, but are less common. It would not surprise me if 
a USB optical drive would read and write faster when 
using a power source other than the host. 

> DVD-R would be nice, but is not essential.

That's not a problem anymore. I don't know of any new 
DVD drive that does not read and write all the variations 
of CDs and DVDs. 

> I have an eSATA port, but I think using USB would
> make it more useful

I concur. 
USB ports are much much more common than eSATA ports.