USB3: Why it's a bit harder than USB2

Re:USB3: Why it's a bit harder than USB2 by derefr on Wednesday October 07, 2020 @02:02PM (#24710905)

I always understood Firewire to be a standard designed for complementary use-cases to USB. Firewire isn't an attempt at "USB but better" (though devices could theoretically be made to use it that way); it's an attempt at "powered SCSI, but smaller and more ruggedized." It's a professional-equipment port, designed—on the one hand—for devices like laptops that can't fit the older, full-scale professional-equipment port (like SAS or mini-XLR); and on the other hand, for manufacturers of high-BOM high-margin professional equipment, as an extra port they can slap onto their device to allow these portable devices to connect to them.

In that sense, Firewire is less analogous to a Lambo ("a better car"), and more akin to a truck. But a very tiny truck, designed for both off-roading and portability. Which is to say: an ATV.

An ATV isn't better at being a car than a car is, but it is better at being a truck than a car is (though worse at being a truck than a truck is.) But sometimes, especially in constrained environments (e.g. search-and-rescue in the Alaskan wilderness), a truck won't fit, and a car won't work. So you need an ATV. It's well-engineered for that particular set of constraints.

Which is also the deal with Thunderbolt: it's PCI-e, but smaller and ruggedized, for places PCI-e itself wouldn't work (like a laptop), but where you nevertheless still need PCI-e -alike performance and bus semantics.

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Re:USB3: Why it's a bit harder than USB2 by chungus_khan on Thursday October 08, 2020 @09:22AM (#24718852)

FireWire actually predates USB, and was certainly seen as a competitor during the design process for USB. It was originally drawn up as a general-purpose serial bus, but with a particular eye at replacing external SCSI interfaces. Certainly it's designed to interface with all sorts of professional equipment, but even in this space that particular decision is a poor one because of the universality of 5V components. Early FireWire-equipped laptops varied wildly in actual voltage delivery capabilities, and even Apple's generally capped out at around 9V, and the standard is extremely awkward and expensive to implement on the device side for many classes of devices. The main issue is that devices have to be capable of handling unregulated voltage between 8V-30V. For high-end professional equipment this is obnoxious and expensive, but manageable, but it's a complete nonstarter for nearly all other equipment, and that meant that even as the price of implementing FireWire signaling went down, it couldn't expand into a bunch of spaces it was perfectly capable of working in (including lower-end versions of said professional equipment).

Even including an optional 5V power pin would have improved this situation, and could have put FireWire in a similar situation to Thunderbolt 3 now, capable of functioning with both high-end professional equipment and ordinary consumer devices.

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