Sometimes you just have to archive data in a form that is immutable, and a CDROM is perfect for that. All looked well - add drive, see burn folder show up in Finder, add data, select ‘burn to disk’. New Macbook M4 Pro - surely that would be a breeze.
Except that none of it worked. The USB drive I had was recognised, but as soon as I inserted a target CD the drive would disappear in Finder and the Mac (on Tahoe 26.2) would pretend the drive no longer even existed. A commercial movie DVD would start up after 30 seconds of making ticking sounds. So, I bought one of a more known brand (ASUS Zendisk) which has its own USB-C cable.
Which didn’t work either. And neither on the Macbook Air M4 I had from work. But on a Linux box I quickly built both drives worked fine. Ergo, the problem was the Macbook, and by the way the drive misbehaved (by ticking) it felt like a power issue.
I hooked up a USB-C hub to a USB-C power supply and connected Mac and DVD toaster so that the toaster would be powered from the hub instead of the Macbook, and presto, all worked as advertised.
Conclusion: if you want to use an external DVD writer with a modern Macbook, use a powered hub.
After a chat with Apple support it emerged that the USB-C ports of a Macbook are good for about 900mA. Using a USB power meter I measured a drive startup peak current of 1.1A, which would cause the USB-C current controller in the Macbook to indeed disconnect and try again later - ergo the ticking sound. QED..
A standard USB 3 port’s power limit is 900 mA, unless the device uses the PowerDelivery API to request more.
Apple’s no-longer-sold SuperDrive requires more, but it uses a proprietary mechanism to request and get it. But that protocol works with my M4 mini (directly connected using a USB A-C adapter).
A bus-powered drive really shouldn’t try to draw more than 900 mA, because there’s no guarantee that it can be supplied.
But I wonder if the Macbook was even providing that much. I’ve seen (other) laptop computers, where the USB ports don’t provide maximum power when the computer is running from battery, but only when connected to a power adapter.
Alternatively, one can a DVD burner/reader that’s powered off of a wall socket, as opposed to running off USB.
Admittedly, this isn’t an optimal solution for on-the-go disc burning/reading. But for desktop Macs, it’s nice to know the drive has the power it needs — even if you’re calling on it to burn an MDISC Blu-Ray.
As it happens I just purchased a second Tekera powered hub. The first I bought a few years ago for my LG monitor USB port (the monitor connects to, and powers, my M2 MBA with USB-c) so I could connect a Bluray drive, an SSD and various devices.
The second one is for my legacy 2017 iMac that was having difficulty powering several USB devices and, in any case, it was awkward to connect devices to the ports on the back.
The MBA is currently running Sequoia and reading/writing Bluray disks is working. From the above discussion, I wonder if Tahoe will cause problems?
As far as I can tell you’ll be fine, provided a hub with enough power supplies the external drive and not the MBA. Once the power issue was addressed I was even able to use the basic disk creation facilities in Finder - as a matter of fact, those then showed up automatically.
That said, I have no idea if Bluray demands more power as my needs never exceeded the 4.7GB space of a single sided DVD, let alone its DL cousin. The ASUS Zendrive V1M I use is M-DISC capable and those demand a bit more oompf as well due to the different materials used (hence the reduced writing speed), but I have no power measurements for it. They’re a tad on the pricey side to experiment with as they’re marketed as capable of outlasting the heat death of the Universe .
I’ve just got an external USB-C noname DVD burner from Aliexpress yesterday, with Matshita UJ8A7AS inside, and took the case away. The label on it says it requires 5V and 1.6A. My MacBook Pro M1 probably provides the necessary power, as I was able to record a couple of discs, including a double-layer DVD+R and DVD+RW (which was erased beforehand). So, the hypothesis about 900mA port limitation looks somewhat doubtful to me.
Observations like this don’t necessarily mandate your conclusion. There may be other factors involved, including:
The device may not require its maximum current in order to function.
The enclosure may have a capacitor or other power-storage circuit to help it get through momentary power spikes without increasing the load on the host computer.
The device may fall-back to lesser capabilities (maybe slower maximum burn speeds) if it can’t get as much current as it wants.
The 900 mA port limitation is part of the USB 3 specification - up to 6 units of 150 mA each (USB versions 1 and 2 specify up to 5 units of 100 mA each, for a 500 mA limit). Devices that require more power must explicitly negotiate for it using the Power Delivery specification.
That drive’s enclosure may be implementing PD. If the Mac is too, then it may be able to deliver more.
.