USB DVD Drive not recognized

[Qqmike]

I'll be darned. Learn something new every day. So, GG, the external DVD unit does not plug into any electrical source; instead, it powers off the USB?

And this re the OP: How did you use the DVD unit before, with just the single USB cable (not the split-double)?

[jglen490]

The y-cable feeds power from two USB ports in parallel (same voltage, double amp capacity) to power devices having with higher power requirements than one USB port can provide. I've only run across a few devices that actually need more power, but it's handy just having one or two y-cables around - and they are cheap.

[Qqmike]

OK, jglen, so when you build a PC, and have a DVD unit in one drive bay, you usually connect the USB cable between the mobo and the DVD. Then you take a Molex cable from the power supply and connect that to your DVD unit. Two equivalent ways of providing power to a DVD? (The OP has an external DVD unit as opposed to an internal unit in a drive bay ... an issue?)

[jglen490]

The OP's DVD drive is a USB drive, which makes it an external connected drive, not an internal mounted. The internal mounted drive, with its molex connector gets ample amperage via that connection. The external drives, if they require a higher amperage level, need the y-cable. The USB port standard is defined with a specific power maximum, which is fine for most devices, but where power requirements are higher then it is necessary to effectively place two USB ports in parallel which covers the increased output needed by the device.

[Qqmike]

@jglen490, got it, thanks.

[GreyGeek]

I'll be darned. Learn something new every day. So, GG, the external DVD unit does not plug into any electrical source; instead, it powers off the USB?

And this re the OP: How did you use the DVD unit before, with just the single USB cable (not the split-double)?

The USB CDROM model that I referenced above came with the Y cable and has always worked. I have never tried to run it with one cable because if the CDROM tried to draw too much load it could potentially damage the USB socket.

External USB CDROM drives used to be powered from USB 2.0 ports. Because a 2.0 port can supply only 100ma the Y cable, which has two USB plugs on one end and a subminiture plug on the other, supplies current from two USB 2.0 ports. Just one won't supply the necessary current at 5V. Most USB CDROM drivers made for USB 3.0 ports have only one USB plug opposite the sub D connection because the USB 3.0 port supplies more than twice the power, and the manufacturers designed their device to run only on a USB 3.0 IF you plug it into a USB 2.0 port it may cough and stutter, if it runs at all. Cheaper computers and small notebook and laptops have cheap USB 2 ports as well. So that I don't risk my USB 2.0 ports I plugged an AC powered USB 2.0 HUB into one of my USB 2.0 ports. It gives me SEVEN USB 2.0 ports to play with.

Strangley, I also have a single USB 3.0 port. (They have the blue plastic inside the plug, as opposed to the black plastic for 2.0). When I bought an unpowered USB 3.0 HUB it would not work when I plugged in four USB memory sticks to take advantage of the faster USB 3.0 speeds when I was testing Btrfs formatted USB sticks as part of a Btrfs memory pool that I used to learn how RAID1 and other levels worked. I may have to buy a powered USB 3.0 HUB.

[Qqmike]

Interesting. As I said, learn something new every day. This is a case of "Gee, I never thought about it!" In my DIY PC builds, I always use internal CD/DVD units, not external. Just now, I actually took a look inside my case to see that the internal DVD unit plugs into a SATA6G port on the motherboard, and has the Molex power connector from the power supply, as it should--a whole different case than what you guys are talking about with the external DVD unit which must--somehow--be convenient, plug-able, and powered, thus the USB route.

[GreyGeek]

Hardware is changing faster than I can keep up with.