I just purchased a Framework 13, with a storage expansion module. I understand that some people use these modules for dual+ boot purposes; my use case is that it is handy to have a detachable usb drive that doesn’t interfere with throwing the laptop in a bag, etc. while attached, similar to how some tablets have a built-in stylus. My employer has policies that require strict separation between my work and non-work usb sticks, and it is helpful to have a stick that I know I can plug into my non-work laptop without rendering its data unusable.
My question is, is there any reason such a device has to use up one of the four usb ports on the machine? Couldn’t it have something like a two-port USB hub built into it, with the first port managing internal storage and the second port residing on the exterior face of the device?
I’m not well versed in the hardware aspects of these things, but I could imagine that the power requirements of a good USB drive don’t leave much room to support a second device. My counter-arguments to this are:
I could still connect a mouse, keyboard, or similar.
For my use case the USB drive doesn’t need to be that great.
One of the expansion ports needs to have a usb c connector and connects to a power source already.
I would pay a bit extra for a built-in usb stick that fits in an expansion slot that I’m already reserving for power, and I feel others would too.
Is there a technical obstacle to making one? Has somebody already made one?
For this particular use, powering the laptop while also using USB for something else, there is unfortunately significant technical obstacles.
USB PD (Power Delivery) uses progressively higher voltages, up to 48 volts, as wattage increases. It only uses 5 volts, the standard voltage that normal peripherals need, at 15 watts or lower. A 60 watt charger is providing 20 volts. A USB drive would be destroyed by that. So an isolated power supply would need to be created by stepping down the voltage to 5 volts. This would take a certain amount of room, and there just isn’t enough room to do it easily or cheaply. Possibly not enough period. And we haven’t yet even got to other challenges for supporting USB PD.
The main thing about passthrough USB is that it wouldn’t have all the features of the laptop’s USB port.
Thunderbolt/USB4 is hard to pass through as you need higher quality circuit board and the hub chips for those things are expensive.
Likewise with the charging - one of the forum members tried creating an expansion card with two USB-C ports and what they discovered is that charging passthrough heats the chips inside the expansion card enough that the charging power has to be limited.
I suspect those compromises in experience and added confusion are what discourages Framework from doing this. The USB-C port will look the same on the outside, but it will work differently from other USB-C ports. (And USB-A plug takes up too much space to put an SSD in)