6 ms·

Apple/Intel Thunderbolt does not have this problem in my experience. USB has always been the cheapest alternative (remember Firewire?). Add to that the sheer in

Apple/Intel Thunderbolt does not have this problem in my experience. USB has always been the cheapest alternative (remember Firewire?). Add to that the sheer incompetence of the USB committee (see the USB PD spec, or USB Audio) and its a miracle anything works at all.

izacus 6y ago
Yeah, we remember FireWire. And all the burned out FW ports due to poor power regulation on cameras and devices. I don't think I've ever seen a connection protocol more likely to damage a device on either end of the connection. USB is a massive imporovement here.
- mixmastamyk 6y ago
  > FireWire --> burned out ports Sounds like it delivered what it said on the tin!
- marcan_42 6y ago
  FireWire is a much better design than USB in many ways. I still use a FireWire audio interface purchased not that long ago (though now it has to go through a Thunderbolt adapter). The problem with USB 1 and 2 is that it was designed by insane committee. This resulted in stuff like those versions not using true differential signaling (like USB3 does) even though that was common technology at the time. Instead they have end of packets delimited by single-ended conditions. That, coupled with a single ground wire for power and data makes for a world of ground loop issues. And then they made the frame rate 1kHz, which is right in the peak of human hearing sensitivity. And so, USB's terrible design is single-handedly responsible for a huge amount of, even most, noise and interference issues in audio systems involving it. Especially in low cost consumer hardware, but it has made its way into many professional productions. Any time you hear a constant 1kHz beep of interference, mixed with some fuzzy crackling, nine times out of ten that's a ground loop with USB and audio involved. It's everywhere once you listen closely. Headphone output on your laptop or phone is noisy when you access a USB drive, or has a 1k beep? USB. USB audio widget has background fuzz and a beep? USB. Slight 1k beep in the background of a news cast? Someone had the bright idea of using USB somewhere along the line. It didn't have to be this way. Ethernet, SATA, plenty of other protocols use proper differential signaling and don't have this issue. How to do this properly was well established long before USB existed. And to add insult to injury, while USB 2 specifies a transaction translator, so you can run USB 1 devices on a USB 2 bus, USB 3 does not. And so, while USB 3 devices don't have this problem any more, you can't plug in a USB 2 device into a USB 3 bus or a USB 3 hub. And nobody uses USB 3 for low channel count audio interfaces, so this problem will remain forever. Oh sure, you can plug it into a USB 3 port, which is actually a USB 3 port and a USB 2 port in one. And you can plug it into a hub labeled "USB 3" which actually has a whole USB 2 hub along side it in parallel. The communication from USB 2 devices remains USB 2 all the way to the host. And so, not only do USB 2 devices only get 480Mbps of total bandwidth on a USB "3" hub (minus a ton of overhead, because the protocol is terrible), it doesn't fix this issue! And did I mention USB 2 is impossible to galvanically isolate in any kind of cost-effective way? I could go on and on about how the polled architecture causes performance bottlenecks, about how it's impossible to tunnel without unfixable corner cases, about how its latency requirements preclude lots of innovative ideas, about how the descriptor and device inquiry protocols are practically designed to guarantee that implementations are vulnerable and have exploitable bugs (yes, your USB stack is vulnerable. They all are. This is how the PS3 got hacked. And the Switch. And tons of other devices. USB developers like me know misbehaving USB devices crash hosts all the time). I don't like USB.
  - my123 6y ago
    And the iPhone too... (checkm8 is... a USB stack bug)
  - shawnz 6y ago
    These factors don't come close to negating the incredible convenience that USB has afforded me over the last couple of decades. So, the committee must have done something right.
    - marcan_42 6y ago
      Just because a technology is better than nothing or became popular doesn't mean it's good. There is plenty of bad engineering in the world that might be better than no engineering, but that doesn't mean we wouldn't have all been better off with a good design from the start.
      - shawnz 6y ago
        But it's not just better than nothing. It is good, even great. It does exactly what I need without issue and has worked reliably for me for decades. It may not be perfectly elegant and beautiful in every technical aspect of its design but that doesn't really matter to me. You might say Firewire could have provided the same for me, but Firewire wasn't widely deployed or adopted. Therefore it could not have replaced USB for my use cases. That may not be a technical issue, but I don't really care as a user if the failure of Firewire is technical or not. Technical superiority is only a small piece of the puzzle. Plus, I think you are underestimating the technical advantages which led to USB's success (e.g. low cost).
        usr1106 6y ago
        > It is good, even great. It does exactly what I need without issue and has worked reliably USB1 and USB2 still work fine despite being less than ideal engineering. Tolerances are big enough at lower speeds. USB3 can be unreliable (e.g. for cameras) because limits set by the laws of physics get too close for cheap implementations. That's no longer good. Especially if we are forced to use that in professional set-ups, where a couple of cents or even Euros/dollars would not harm. The problem is now that you cannot put that tiny bit of money on the table and you get a reliable product. As the discussion showed even certified and known brands' USB3 products can be unreliable.
- crest 6y ago
  I remember powering two 3.5" 7200rpm from a single firewire port for years. Even a third disk daisy chained from a single port didn't require an external power supply. I miss the user experience made possible by the high bus voltage. USB PD is worse.
josefx 6y ago
Any external Thunderbolt device also gains direct memory access to your system, resulting in a list of related security issues. Of course speed over security is classic Intel.
- wtallis 6y ago
  Those DMA attacks can be blocked by the OS properly configuring an IOMMU. Intel stopped using IOMMU support on CPUs for product segmentation by the time Thunderbolt 3 arrived, and even before that it was difficult to find a Thunderbolt-equipped system that didn't have IOMMU capability.
  - josefx 6y ago
    > Those DMA attacks can be blocked by the OS properly configuring an IOMMU Wikipedia seems to state no OS has managed to do so (as of 2019). Thunderbolt had been around since 2011. > Intel stopped using IOMMU support on CPUs for product segmentation by the time Thunderbolt 3 arrived So it couldn't possibly be made secure before 2015 and still wont be secure until $UNIVERSE_HEATDEATHDATE .
    - wtallis 6y ago
      > So it couldn't possibly be made secure before 2015 You're wildly misunderstanding things. Up to 2015, it was possible to build a new PC that lacked the necessary hardware features, primarily by choosing one of Intel's enthusiast-oriented overclockable CPU models (which used to have the IOMMU disabled for product segmentation reasons). But it was still very much possible to get all the necessary hardware features by selecting the next slower speed grade of the same chip, or by buying almost any pre-built system equipped with Thunderbolt ports. And since then, it's been almost impossible to build a PC that lacks the necessary hardware security features, because pretty much the only Intel CPUs still in production that lack IOMMU capabilities are Atom parts which aren't socketed and probably aren't used in any Thunderbolt-capable machines. > Wikipedia seems to state no OS has managed to do so (as of 2019). Thunderbolt had been around since 2011. You should read more carefully, and preferably follow the link to the source paper. That paper points out how Mac OS X started using the IOMMU to protect against DMA attacks in 2012, Linux and FreeBSD likewise have such capabilities, Windows pretty much doesn't (no longer true). The point of that paper cited on Wikipedia was to show that when operating systems poke holes in the IOMMU protection to allow certain devices to perform DMA, it's possible to open up a more exploitable hole than you might expect. In particular, data structures may need to be rearranged to align with the 4kB page protection granularity, or else information that should remain inaccessible to peripherals may be exposed alongside legitimate DMA payload. And it's also possible for a malicious device to spoof the device IDs of a trusted device type and be granted access by default, but that's a class of vulnerability that exists for plain old USB, too. So as I originally stated, the IOMMU is the hardware feature needed to block DMA attacks. But it's only effective when used properly by the OS. That's not trivial—but also not impossible.
TonyTrapp 6y ago
And USB being the cheapest option is the main reason why we finally have a connector and almost all hardware can agree on. Remember that even the fact that the original USB plug is not symmetrical is to due to cost savings - if they added four extra wires for symmetry, we might still not have USB everywhere.
- MrBuddyCasino 6y ago
  > we finally have a connector and almost all hardware can agree on. Do we?
  - TonyTrapp 6y ago
    Compared to what we had at the dawn of USB - yes, absolutely.
  - horsawlarway 6y ago
    Yup. It's going to be a bit before it percolates through to lower price point devices, but I'm a very, very happy usb-c/thunderbolt user. My phone, headphones, drawing tablet, personal laptop, work laptop, and monitors all plug in using a single port. Not just for connectivity, but also for power. It's incredibly liberating. Everything charges from the same charger, everything plugs together. I vividly remember the days of trying to find the right wall wart for the right device. I can't tell you how happy I am that my work laptop and personal laptop can both share chargers. That alone would make me ecstatic. That my phone/headphones/tablet also all work with just that charger is candy on top. That my monitor can provide that power while also using the same cable for display in? Incredible! There are absolutely still issues, and it requires more research than it should, but once it works, it's SO DAMN NICE that I simply can't imagine going back.
baybal2 6y ago
> Add to that the sheer incompetence of the USB committee In contrast to the sheer idiocy of demanding a "pocket change" fee of $1 per port, which made FireWire an instant turnoff for most device makers not targeting Western markets, and singlehandedly killed FireWire as a standard. FireWire was possibly better engineered, but USB was better marketed.
- MrBuddyCasino 6y ago
  Yes, they were delusional. Economics trumps engineering, always.
  - stjohnswarts 6y ago
    definitely. Accounting will almost always win the fight unless what they want completely renders the product useless. Apple is one of the few companies I've worked for where that wasn't always the case.
- throwaway9870 6y ago
  > FireWire was possibly better engineered, but USB was better marketed. Yes, perhaps, but it had a big drawback. You could not build a Firewire device with a single die because of the high voltages. This added cost to the USB device (memory stick, etc) meant it would never be price competitive with USB. I was a member of a USB working group and was amazed when a member from a large Japanese company explained that to me. Up to that point, I had not been exposed to the low-end (as in price) of the USB market and didn't realize the significance of this issue. These manufactures would bring the 5V straight into their IC and drop the voltage on-chip. That is actually fairly difficult in the age of such small chip geometries, but basically impossible for Firewire which is 8V to 30V. The USB market is driven by the low-end, so Firewire never had a chance because of an engineering specification.
  - chungus_khan 6y ago
    This isn't brought up enough when people talk about FireWire and "good engineering". Good engineering means practical engineering. It means things like choosing a sane, common voltage that is well suited to the already-existing real world. Picking 8V-30V is the kind of decision that sounds beautiful to a utopian engineer working high in an office tower, and I'm sure it would be lovely if we could have instantly warped into a world of full adoption, but here in the real world your standard is going to have to be useful today, and it's going to have to be useful with more than just brand-new top-of-the-line freshly designed kit. Any engineer who would willingly forgo access to the entire world of already-existing 5V ICs is not a good engineer in my books. To be fair to them though, it's very easy to get caught up in the beauty of those theoretical designs and forget that the best-selling car is a Toyota Corolla, not a Lamborghini.

izacus 6y ago

Yeah, we remember FireWire. And all the burned out FW ports due to poor power regulation on cameras and devices. I don't think I've ever seen a connection protocol more likely to damage a device on either end of the connection. USB is a massive imporovement here.

mixmastamyk 6y ago
> FireWire --> burned out ports Sounds like it delivered what it said on the tin!
marcan_42 6y ago
FireWire is a much better design than USB in many ways. I still use a FireWire audio interface purchased not that long ago (though now it has to go through a Thunderbolt adapter). The problem with USB 1 and 2 is that it was designed by insane committee. This resulted in stuff like those versions not using true differential signaling (like USB3 does) even though that was common technology at the time. Instead they have end of packets delimited by single-ended conditions. That, coupled with a single ground wire for power and data makes for a world of ground loop issues. And then they made the frame rate 1kHz, which is right in the peak of human hearing sensitivity. And so, USB's terrible design is single-handedly responsible for a huge amount of, even most, noise and interference issues in audio systems involving it. Especially in low cost consumer hardware, but it has made its way into many professional productions. Any time you hear a constant 1kHz beep of interference, mixed with some fuzzy crackling, nine times out of ten that's a ground loop with USB and audio involved. It's everywhere once you listen closely. Headphone output on your laptop or phone is noisy when you access a USB drive, or has a 1k beep? USB. USB audio widget has background fuzz and a beep? USB. Slight 1k beep in the background of a news cast? Someone had the bright idea of using USB somewhere along the line. It didn't have to be this way. Ethernet, SATA, plenty of other protocols use proper differential signaling and don't have this issue. How to do this properly was well established long before USB existed. And to add insult to injury, while USB 2 specifies a transaction translator, so you can run USB 1 devices on a USB 2 bus, USB 3 does not. And so, while USB 3 devices don't have this problem any more, you can't plug in a USB 2 device into a USB 3 bus or a USB 3 hub. And nobody uses USB 3 for low channel count audio interfaces, so this problem will remain forever. Oh sure, you can plug it into a USB 3 port, which is actually a USB 3 port and a USB 2 port in one. And you can plug it into a hub labeled "USB 3" which actually has a whole USB 2 hub along side it in parallel. The communication from USB 2 devices remains USB 2 all the way to the host. And so, not only do USB 2 devices only get 480Mbps of total bandwidth on a USB "3" hub (minus a ton of overhead, because the protocol is terrible), it doesn't fix this issue! And did I mention USB 2 is impossible to galvanically isolate in any kind of cost-effective way? I could go on and on about how the polled architecture causes performance bottlenecks, about how it's impossible to tunnel without unfixable corner cases, about how its latency requirements preclude lots of innovative ideas, about how the descriptor and device inquiry protocols are practically designed to guarantee that implementations are vulnerable and have exploitable bugs (yes, your USB stack is vulnerable. They all are. This is how the PS3 got hacked. And the Switch. And tons of other devices. USB developers like me know misbehaving USB devices crash hosts all the time). I don't like USB.
- my123 6y ago
  And the iPhone too... (checkm8 is... a USB stack bug)
- shawnz 6y ago
  These factors don't come close to negating the incredible convenience that USB has afforded me over the last couple of decades. So, the committee must have done something right.
  - marcan_42 6y ago
    Just because a technology is better than nothing or became popular doesn't mean it's good. There is plenty of bad engineering in the world that might be better than no engineering, but that doesn't mean we wouldn't have all been better off with a good design from the start.
    - shawnz 6y ago
      But it's not just better than nothing. It is good, even great. It does exactly what I need without issue and has worked reliably for me for decades. It may not be perfectly elegant and beautiful in every technical aspect of its design but that doesn't really matter to me. You might say Firewire could have provided the same for me, but Firewire wasn't widely deployed or adopted. Therefore it could not have replaced USB for my use cases. That may not be a technical issue, but I don't really care as a user if the failure of Firewire is technical or not. Technical superiority is only a small piece of the puzzle. Plus, I think you are underestimating the technical advantages which led to USB's success (e.g. low cost).
      - usr1106 6y ago
        > It is good, even great. It does exactly what I need without issue and has worked reliably USB1 and USB2 still work fine despite being less than ideal engineering. Tolerances are big enough at lower speeds. USB3 can be unreliable (e.g. for cameras) because limits set by the laws of physics get too close for cheap implementations. That's no longer good. Especially if we are forced to use that in professional set-ups, where a couple of cents or even Euros/dollars would not harm. The problem is now that you cannot put that tiny bit of money on the table and you get a reliable product. As the discussion showed even certified and known brands' USB3 products can be unreliable.
crest 6y ago
I remember powering two 3.5" 7200rpm from a single firewire port for years. Even a third disk daisy chained from a single port didn't require an external power supply. I miss the user experience made possible by the high bus voltage. USB PD is worse.

josefx 6y ago

Any external Thunderbolt device also gains direct memory access to your system, resulting in a list of related security issues. Of course speed over security is classic Intel.

wtallis 6y ago
Those DMA attacks can be blocked by the OS properly configuring an IOMMU. Intel stopped using IOMMU support on CPUs for product segmentation by the time Thunderbolt 3 arrived, and even before that it was difficult to find a Thunderbolt-equipped system that didn't have IOMMU capability.
- josefx 6y ago
  > Those DMA attacks can be blocked by the OS properly configuring an IOMMU Wikipedia seems to state no OS has managed to do so (as of 2019). Thunderbolt had been around since 2011. > Intel stopped using IOMMU support on CPUs for product segmentation by the time Thunderbolt 3 arrived So it couldn't possibly be made secure before 2015 and still wont be secure until $UNIVERSE_HEATDEATHDATE .
  - wtallis 6y ago
    > So it couldn't possibly be made secure before 2015 You're wildly misunderstanding things. Up to 2015, it was possible to build a new PC that lacked the necessary hardware features, primarily by choosing one of Intel's enthusiast-oriented overclockable CPU models (which used to have the IOMMU disabled for product segmentation reasons). But it was still very much possible to get all the necessary hardware features by selecting the next slower speed grade of the same chip, or by buying almost any pre-built system equipped with Thunderbolt ports. And since then, it's been almost impossible to build a PC that lacks the necessary hardware security features, because pretty much the only Intel CPUs still in production that lack IOMMU capabilities are Atom parts which aren't socketed and probably aren't used in any Thunderbolt-capable machines. > Wikipedia seems to state no OS has managed to do so (as of 2019). Thunderbolt had been around since 2011. You should read more carefully, and preferably follow the link to the source paper. That paper points out how Mac OS X started using the IOMMU to protect against DMA attacks in 2012, Linux and FreeBSD likewise have such capabilities, Windows pretty much doesn't (no longer true). The point of that paper cited on Wikipedia was to show that when operating systems poke holes in the IOMMU protection to allow certain devices to perform DMA, it's possible to open up a more exploitable hole than you might expect. In particular, data structures may need to be rearranged to align with the 4kB page protection granularity, or else information that should remain inaccessible to peripherals may be exposed alongside legitimate DMA payload. And it's also possible for a malicious device to spoof the device IDs of a trusted device type and be granted access by default, but that's a class of vulnerability that exists for plain old USB, too. So as I originally stated, the IOMMU is the hardware feature needed to block DMA attacks. But it's only effective when used properly by the OS. That's not trivial—but also not impossible.

TonyTrapp 6y ago

And USB being the cheapest option is the main reason why we finally have a connector and almost all hardware can agree on. Remember that even the fact that the original USB plug is not symmetrical is to due to cost savings - if they added four extra wires for symmetry, we might still not have USB everywhere.

MrBuddyCasino 6y ago
> we finally have a connector and almost all hardware can agree on. Do we?
- TonyTrapp 6y ago
  Compared to what we had at the dawn of USB - yes, absolutely.
- horsawlarway 6y ago
  Yup. It's going to be a bit before it percolates through to lower price point devices, but I'm a very, very happy usb-c/thunderbolt user. My phone, headphones, drawing tablet, personal laptop, work laptop, and monitors all plug in using a single port. Not just for connectivity, but also for power. It's incredibly liberating. Everything charges from the same charger, everything plugs together. I vividly remember the days of trying to find the right wall wart for the right device. I can't tell you how happy I am that my work laptop and personal laptop can both share chargers. That alone would make me ecstatic. That my phone/headphones/tablet also all work with just that charger is candy on top. That my monitor can provide that power while also using the same cable for display in? Incredible! There are absolutely still issues, and it requires more research than it should, but once it works, it's SO DAMN NICE that I simply can't imagine going back.

baybal2 6y ago

> Add to that the sheer incompetence of the USB committee In contrast to the sheer idiocy of demanding a "pocket change" fee of $1 per port, which made FireWire an instant turnoff for most device makers not targeting Western markets, and singlehandedly killed FireWire as a standard. FireWire was possibly better engineered, but USB was better marketed.

MrBuddyCasino 6y ago
Yes, they were delusional. Economics trumps engineering, always.
- stjohnswarts 6y ago
  definitely. Accounting will almost always win the fight unless what they want completely renders the product useless. Apple is one of the few companies I've worked for where that wasn't always the case.
throwaway9870 6y ago
> FireWire was possibly better engineered, but USB was better marketed. Yes, perhaps, but it had a big drawback. You could not build a Firewire device with a single die because of the high voltages. This added cost to the USB device (memory stick, etc) meant it would never be price competitive with USB. I was a member of a USB working group and was amazed when a member from a large Japanese company explained that to me. Up to that point, I had not been exposed to the low-end (as in price) of the USB market and didn't realize the significance of this issue. These manufactures would bring the 5V straight into their IC and drop the voltage on-chip. That is actually fairly difficult in the age of such small chip geometries, but basically impossible for Firewire which is 8V to 30V. The USB market is driven by the low-end, so Firewire never had a chance because of an engineering specification.
- chungus_khan 6y ago
  This isn't brought up enough when people talk about FireWire and "good engineering". Good engineering means practical engineering. It means things like choosing a sane, common voltage that is well suited to the already-existing real world. Picking 8V-30V is the kind of decision that sounds beautiful to a utopian engineer working high in an office tower, and I'm sure it would be lovely if we could have instantly warped into a world of full adoption, but here in the real world your standard is going to have to be useful today, and it's going to have to be useful with more than just brand-new top-of-the-line freshly designed kit. Any engineer who would willingly forgo access to the entire world of already-existing 5V ICs is not a good engineer in my books. To be fair to them though, it's very easy to get caught up in the beauty of those theoretical designs and forget that the best-selling car is a Toyota Corolla, not a Lamborghini.