Recently I purchased a SATA to USB adapter. To be able to access 2.5-inch (laptop) and 3.5-inch (desktop) hard drives.
To my surprise, there is a board to do the conversion.
Why there should be a board to do the conversion? Why the conversion process is so complex that a board is required?
As pointed out by @Justme the above device has a USB socket problem. A proper device-side USB socket would look like a well-designed external HDD:
Yes, without going to details, it's complex, and it's because USB and SATA are completely different protocols, intended for completely different applications. They use different electrical signaling, different line coding, different packet structure, everything.
You need a chip that can do the conversion.
The chip needs to be placed somewhere, and it needs connections to USB connector and power supply connector, and internally to SATA connector.
The chip, connectors, and components that do the required power supply conversion are best done with a PCB.
Also, it is clearly a poor quality design. They did not even bother to put the correct USB connector there.
They put a host-side socket to a device that should obviously have a device side socket. You now possess a possibly dangerous USB cable which allows you to make connections between devices that you are not supposed to make and can damage the devices.
