Thread: Ubiquitous USB
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chucker
 
Join Date: May 2004
Location: near Bremen, Germany
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2022-09-02, 14:46

They’re conceptually different. USB defines device classes (HID for keyboards, mice, etc., mass storage for, y’know, and so on). Thunderbolt is basically just external PCIe. There’s overlap (see, for example, SSDs), but fundamentally Thunderbolt operates at a lower level.

For example, if you do an eGPU with USB like DisplayLink has done, it’s more of an emulation hack; if you do one with Thunderbolt, the OS can just treat it as a PCIe device, with the added quirk of hot-plugging ability.

Thunderbolt is, always has been, and always will be more niche than USB. USB’s speeds catching up may make indeed it even less useful. And I’m not sure what the future will be for ARM Macs, what with Apple apparently not wanting to bring eGPU to ARM. But there will always be use cases that are awkward or impossible to do in USB.

(PCIe itself is also getting less and less useful. There was a time you’d have sound, Ethernet, SCSI, etc. on separate ISA/VLB/AGP/NuBus/PCI/PDS cards. Then motherboards offered more and more of that. Now SoCs do.)

Last edited by chucker : 2022-09-03 at 02:02.
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