揭一个坑，LOMA LINDA的CFG,不点名了，珍惜生命，远离这个坑吧# Biology - 生物学
p*m
1 楼
你等的不耐烦了吗
usb4今年即将闪亮登场
USB 4: Everything We Know So Far
by Avram Piltch March 7, 2019 at 12:45 PM
Get ready for a whole new generation of USB. The USB Promoter Group recently
announced that a new standard, “USB4” (official spelling lacks a space,
but we’re using one in this article to reflect the way readers search),
will be released later this year with products that utilize the technology
likely to come much later. USB 4 promises a host of benefits that include
faster transfer speeds, better management of video and optional
compatibility with Thunderbolt 3.
Credit: Shutterstock / Sergei Kardashev
Credit: Shutterstock / Sergei Kardashev
In a world where there are four different versions of USB 3.2, two types of
USB 3.1 and a host of connector types and power specs, the idea of a new
standard might seem overwhelming. However, there’s also a lot to look
forward to. Here’s everything you need to know about USB 4.
Main Benefits of USB 4
The new USB 4 standard will have three main benefits over prior versions of
USB.
40 Gbps Maximum Speed: By using two-lane cables, some devices will be able
to operate at up to 40 Gbps, the same speed as Thunderbolt 3.
Compatible with Thunderbolt 3 devices: Some, but not necessarily all USB 4
implementations will also work with Thunderbolt 3 devices.
Better Resource Allocation for Video: If you’re using a USB 4 port to
transport both video and data at the same time, the port will allocate
bandwidth accordingly. So, if the video only needs 20 percent of the
bandwidth to drive your 1080p monitor that’s also a hub, the other 80
percent will be free for transferring files from your external SSD.
Will Use Type-C Ports
This almost goes without saying: USB 4 will only operate over the Type-C
connector. Don’t expect to see a USB 4 device or hub with old-fashioned
Type-A ports. That’s no surprise, as other recent standards such as USB
Power Delivery only work on Type-C. If you do connect to, for example, a
Type-A 3.1 port by using an adapter, the speed and power will drop down to
the lowest common denominator.
Credit: Shutterstock / Schuchrat Kurbanov
Credit: Shutterstock / Schuchrat Kurbanov
Compatible With Thunderbolt 3, Sort-Of
Intel made news when it said it had given the Thunderbolt 3 protocol to USB
Promoter Group, allowing devices with USB 4 ports to potentially be
compatible with Thunderbolt 3 devices and USB 4 devices to attach to
Thunderbolt 3. That’s good news for everyone, especially laptop users who
want to play games by connecting an eGPU (external graphics card).
Though there are a number of Thunderbolt 3 eGPUs out there, few laptops and
desktops come with Thunderbolt 3 and almost no motherboards support
Thunderbolt 3 out of the box. Because Thunderbolt is an Intel standard, you
won’t find it on any AMD-powered computer. Thunderbolt 3 is also more
expensive to implement than standard USB, because it’s not an open standard
and it requires an extra chip. So today, if you want an eGPU or a super-
speedy Thunderbolt 3 storage drive, your choice of computer is very limited.
With USB 4, device and host manufacturers won’t have to pay Intel any
royalties so there’s a much better chance of mass adoption. However, there
’s a catch: Thunderbolt compatibility is not a required part of the USB 4
spec so manufacturers don’t have to implement it. You could end up buying a
laptop with USB 4 and find that it doesn’t work with, say, your Razer Core
X graphics dock. However, USB Promoter Group CEO Brad Saunders anticipates
that most PCs with USB 4 will be made to work with Thunderbolt 3.
“We do expect PC vendors to broadly support Thunderbolt backward
compatibility, because most of what they need is already built into the USB
4 design,” Saunders said. “It’s based on the same technology so we do
anticipate a high rate of adoption there, but the phone guys will probably
choose not to add the extra little bit they need to be backward compatible.”
Though Saunders is optimistic about PC manufacturers adding Thunderbolt 3
compatibility to their USB 4 ports, we should note that any device which
wants to market itself as Thunderbolt 3 compatible will probably need to be
certified by Intel. Today, any Thunderbolt 3 product has to undergo a
rigorous validation process that costs money.
Three Speeds of USB 4
Though it can hit theoretical speeds of up to 40 Gbps, not all USB devices
or hosts will support that standard. Saunders told us that there will be
three speeds: 10 Gbps, 20 Gbps and 40 Gbps. Expect smaller and less-
expensive devices such as phones and Chromebooks to use one of the lower
speeds and, when you do get a laptop, you’ll need to make sure to look at
the specs if you want the fastest USB 4 connection available.
Great at Sharing Bandwidth Between Video and Data
A big part of the USB 4 spec is the ability to dynamically adjust the amount
of resources that are available when you are sending both video and data
over the same connection. So, let’s say that you have USB 4 with a 40 Gbps
maximum and you’re outputting to a 4K monitor while copying a ton of files
from an external SSD. And let’s stipulate that the video feed needs about
12.5 Gbps. In that case, USB 4 would allocate the remaining 27.5 Mbps to
your backup drive.
USB-C introduced “alternative mode,” the ability to transmit DisplayPort /
HDMI video from a Type-C port, but the current 3.x spec doesn’t provide a
good way to split up resources. According to Saunders, DisplayPort alt mode
can split the bandwidth between USB data and video data exactly 50/50, and
HDMI alt mode doesn’t allow simultaneous USB data at all.
“With USB SuperSpeed, we didn’t have quite the flexibility in architecture
to really manage those two distinct bandwidths [data and video] in a
combined fashion over the connector,” Saunders said. “So this is really
optimized for more scalability between the different application types.”
Rather than using alternative mode, many current docking stations use
DisplayLink technology, which compresses the video signal and turns it into
USB data. It will be interesting to see whether most USB 4 docks use
alternative mode instead.
All USB 4 Hosts Support USB PD
Where some current-day USB Type-C devices support the USB Power Delivery (
USB PD) standard for carrying electricity to high-powered devices, not all
of them do. Every USB 4 device and host will have to comply with USB PD,
which allows for higher wattages and better power management.
USB PD can theoretically provide up to 100 watts, but charging devices do
not have to support that amount of power. So there’s no guarantee that a
given USB 4 port would give or take the amount that a particular notebook
requires to operate, but you can expect it to follow the spec.
Backward Compatible With Older Device
The best thing about all generations of USB is how well they work together.
USB 4 will work with USB 3 and USB 2 devices and ports. It should go without
saying, though, that you’ll only get the speed and capabilities of the
weakest part of your connection. A USB 4 device won’t be able to transfer
at 40 Gbps when you hook it to a USB 3.2 port and an old-school USB 2 port
won’t suddenly get faster just because you connect it to a brand new USB 4
backup drive.
Your Old Cables Will Work At Their Maximum Speeds
Credit: Shutterstock
Credit: Shutterstock
Your existing USB cables and adapters will work with USB 4, but as with
everything else that’s backward compatible, they will only operate at their
maximum rated speeds. So, if you have a USB 3.1 cable that can operate at 5
Gbps, you’ll only get up to 5 Gbps, even if you are using it to connect a
USB 4 port to a USB 4 device. To get Thunderbolt 3 support, you’ll likely
need a Thunderbolt 3 cable.
Not Coming Anytime Soon
The USB Promoter forum plans to release the specs for USB 4 in the middle of
2019, but don’t expect to see any products based on the standard until
2020. Saunders told us that a typical development cycle for new products is
12 to 18 months.
When it comes to USB 4-enabled laptops and desktops, even 18 months seems
optimistic. The spec for Type-C was announced in 2014 and It took a really
long time for USB Type-C to go mainstream--many laptops still don’t have it.
Will Cost More to Manufacture Than USB 3.2
Another hurdle for mass adoption is the added cost of USB 4. While we don’t
know exactly how much it will cost for PC and device vendors to add USB 4
connectivity, we know that it will require more expensive components than
the latest current standard, USB 3.2.
“I think it’s going to be something less than Thunderbolt, but not as
inexpensive as SuperSpeed in terms of the actual material cost to the
product developer,” Saunders said. “It takes a lot of gates to do it and
the product still does all the SuperSpeed stuff.”
Saunders added that he hopes the costs will come down quickly. However, we’
d guess that the cost differential will push USB 4 onto higher end PCs, at
least at first.
Why USB 4 is Officially Spelled as “USB4” (No Space)
Unlike every other version of USB, the new spec is officially spelled
without a space before the version number. While we think that most people
will probably write it as USB 4, the official name is USB4. USB Promoter
Group CEO Brad Saunders explained that his goal in removing the space was to
take the focus off of version numbers and onto a brand name.
“One of the things I’ve trying to signal right now is that we don’t plan
to get into a 4.0, 4.1, 4.2 kind of iterative path,” he told us. “And we
don’t want it to be associated and used with products as a differentiator .
. . we want to keep it as simple as possible.”
The USB 3.x spec has been filled with different version numbers, including
USB 3.0, USB 3.1 Gen 1, USB 3.1 Gen 2 and four different versions of USB 3.2
, in addition to the presence or absence of optional features such as USB PD
and alternate mode. But Saunders told us that those numbers are really for
developers and he wishes that OEMs would use simpler terms like “SuperSpeed
USB” when marketing their products.
Perhaps because of his concern about marketers throwing too many digits at
consumers, Saunders said the organization does not plan to use version
numbers for spec updates. So, even if there’s a faster iteration in two
years, it will likely still be called USB 4 but with the speed number after
(we imagine something like USB 4 80 Gbps). He and his team still haven’t
decided on a branding strategy, so there may also be a marketing name for
USB 4. Much like USB 3.x is known as “SuperSpeed USB,” USB 4 could end up
with its own moniker (we suggest “Super Duper Speed USB”).
“I want it to be a clear distinction. USB 4 is its own architecture with
its own set of speeds and try not get trapped on these dot releases for
every single speed,” he said. “When and if it goes faster, we’ll simply
have the faster version of the certification and the brand.”
Bottom Line
There’s still a lot more that we don’t know about USB 4 than we do. We’ll
learn a lot more when the spec is released later this year, but whatever
happens, don’t expect to see devices with USB 4 until at least late 2020,
but more likely 2021 and beyond.
usb4今年即将闪亮登场
USB 4: Everything We Know So Far
by Avram Piltch March 7, 2019 at 12:45 PM
Get ready for a whole new generation of USB. The USB Promoter Group recently
announced that a new standard, “USB4” (official spelling lacks a space,
but we’re using one in this article to reflect the way readers search),
will be released later this year with products that utilize the technology
likely to come much later. USB 4 promises a host of benefits that include
faster transfer speeds, better management of video and optional
compatibility with Thunderbolt 3.
Credit: Shutterstock / Sergei Kardashev
Credit: Shutterstock / Sergei Kardashev
In a world where there are four different versions of USB 3.2, two types of
USB 3.1 and a host of connector types and power specs, the idea of a new
standard might seem overwhelming. However, there’s also a lot to look
forward to. Here’s everything you need to know about USB 4.
Main Benefits of USB 4
The new USB 4 standard will have three main benefits over prior versions of
USB.
40 Gbps Maximum Speed: By using two-lane cables, some devices will be able
to operate at up to 40 Gbps, the same speed as Thunderbolt 3.
Compatible with Thunderbolt 3 devices: Some, but not necessarily all USB 4
implementations will also work with Thunderbolt 3 devices.
Better Resource Allocation for Video: If you’re using a USB 4 port to
transport both video and data at the same time, the port will allocate
bandwidth accordingly. So, if the video only needs 20 percent of the
bandwidth to drive your 1080p monitor that’s also a hub, the other 80
percent will be free for transferring files from your external SSD.
Will Use Type-C Ports
This almost goes without saying: USB 4 will only operate over the Type-C
connector. Don’t expect to see a USB 4 device or hub with old-fashioned
Type-A ports. That’s no surprise, as other recent standards such as USB
Power Delivery only work on Type-C. If you do connect to, for example, a
Type-A 3.1 port by using an adapter, the speed and power will drop down to
the lowest common denominator.
Credit: Shutterstock / Schuchrat Kurbanov
Credit: Shutterstock / Schuchrat Kurbanov
Compatible With Thunderbolt 3, Sort-Of
Intel made news when it said it had given the Thunderbolt 3 protocol to USB
Promoter Group, allowing devices with USB 4 ports to potentially be
compatible with Thunderbolt 3 devices and USB 4 devices to attach to
Thunderbolt 3. That’s good news for everyone, especially laptop users who
want to play games by connecting an eGPU (external graphics card).
Though there are a number of Thunderbolt 3 eGPUs out there, few laptops and
desktops come with Thunderbolt 3 and almost no motherboards support
Thunderbolt 3 out of the box. Because Thunderbolt is an Intel standard, you
won’t find it on any AMD-powered computer. Thunderbolt 3 is also more
expensive to implement than standard USB, because it’s not an open standard
and it requires an extra chip. So today, if you want an eGPU or a super-
speedy Thunderbolt 3 storage drive, your choice of computer is very limited.
With USB 4, device and host manufacturers won’t have to pay Intel any
royalties so there’s a much better chance of mass adoption. However, there
’s a catch: Thunderbolt compatibility is not a required part of the USB 4
spec so manufacturers don’t have to implement it. You could end up buying a
laptop with USB 4 and find that it doesn’t work with, say, your Razer Core
X graphics dock. However, USB Promoter Group CEO Brad Saunders anticipates
that most PCs with USB 4 will be made to work with Thunderbolt 3.
“We do expect PC vendors to broadly support Thunderbolt backward
compatibility, because most of what they need is already built into the USB
4 design,” Saunders said. “It’s based on the same technology so we do
anticipate a high rate of adoption there, but the phone guys will probably
choose not to add the extra little bit they need to be backward compatible.”
Though Saunders is optimistic about PC manufacturers adding Thunderbolt 3
compatibility to their USB 4 ports, we should note that any device which
wants to market itself as Thunderbolt 3 compatible will probably need to be
certified by Intel. Today, any Thunderbolt 3 product has to undergo a
rigorous validation process that costs money.
Three Speeds of USB 4
Though it can hit theoretical speeds of up to 40 Gbps, not all USB devices
or hosts will support that standard. Saunders told us that there will be
three speeds: 10 Gbps, 20 Gbps and 40 Gbps. Expect smaller and less-
expensive devices such as phones and Chromebooks to use one of the lower
speeds and, when you do get a laptop, you’ll need to make sure to look at
the specs if you want the fastest USB 4 connection available.
Great at Sharing Bandwidth Between Video and Data
A big part of the USB 4 spec is the ability to dynamically adjust the amount
of resources that are available when you are sending both video and data
over the same connection. So, let’s say that you have USB 4 with a 40 Gbps
maximum and you’re outputting to a 4K monitor while copying a ton of files
from an external SSD. And let’s stipulate that the video feed needs about
12.5 Gbps. In that case, USB 4 would allocate the remaining 27.5 Mbps to
your backup drive.
USB-C introduced “alternative mode,” the ability to transmit DisplayPort /
HDMI video from a Type-C port, but the current 3.x spec doesn’t provide a
good way to split up resources. According to Saunders, DisplayPort alt mode
can split the bandwidth between USB data and video data exactly 50/50, and
HDMI alt mode doesn’t allow simultaneous USB data at all.
“With USB SuperSpeed, we didn’t have quite the flexibility in architecture
to really manage those two distinct bandwidths [data and video] in a
combined fashion over the connector,” Saunders said. “So this is really
optimized for more scalability between the different application types.”
Rather than using alternative mode, many current docking stations use
DisplayLink technology, which compresses the video signal and turns it into
USB data. It will be interesting to see whether most USB 4 docks use
alternative mode instead.
All USB 4 Hosts Support USB PD
Where some current-day USB Type-C devices support the USB Power Delivery (
USB PD) standard for carrying electricity to high-powered devices, not all
of them do. Every USB 4 device and host will have to comply with USB PD,
which allows for higher wattages and better power management.
USB PD can theoretically provide up to 100 watts, but charging devices do
not have to support that amount of power. So there’s no guarantee that a
given USB 4 port would give or take the amount that a particular notebook
requires to operate, but you can expect it to follow the spec.
Backward Compatible With Older Device
The best thing about all generations of USB is how well they work together.
USB 4 will work with USB 3 and USB 2 devices and ports. It should go without
saying, though, that you’ll only get the speed and capabilities of the
weakest part of your connection. A USB 4 device won’t be able to transfer
at 40 Gbps when you hook it to a USB 3.2 port and an old-school USB 2 port
won’t suddenly get faster just because you connect it to a brand new USB 4
backup drive.
Your Old Cables Will Work At Their Maximum Speeds
Credit: Shutterstock
Credit: Shutterstock
Your existing USB cables and adapters will work with USB 4, but as with
everything else that’s backward compatible, they will only operate at their
maximum rated speeds. So, if you have a USB 3.1 cable that can operate at 5
Gbps, you’ll only get up to 5 Gbps, even if you are using it to connect a
USB 4 port to a USB 4 device. To get Thunderbolt 3 support, you’ll likely
need a Thunderbolt 3 cable.
Not Coming Anytime Soon
The USB Promoter forum plans to release the specs for USB 4 in the middle of
2019, but don’t expect to see any products based on the standard until
2020. Saunders told us that a typical development cycle for new products is
12 to 18 months.
When it comes to USB 4-enabled laptops and desktops, even 18 months seems
optimistic. The spec for Type-C was announced in 2014 and It took a really
long time for USB Type-C to go mainstream--many laptops still don’t have it.
Will Cost More to Manufacture Than USB 3.2
Another hurdle for mass adoption is the added cost of USB 4. While we don’t
know exactly how much it will cost for PC and device vendors to add USB 4
connectivity, we know that it will require more expensive components than
the latest current standard, USB 3.2.
“I think it’s going to be something less than Thunderbolt, but not as
inexpensive as SuperSpeed in terms of the actual material cost to the
product developer,” Saunders said. “It takes a lot of gates to do it and
the product still does all the SuperSpeed stuff.”
Saunders added that he hopes the costs will come down quickly. However, we’
d guess that the cost differential will push USB 4 onto higher end PCs, at
least at first.
Why USB 4 is Officially Spelled as “USB4” (No Space)
Unlike every other version of USB, the new spec is officially spelled
without a space before the version number. While we think that most people
will probably write it as USB 4, the official name is USB4. USB Promoter
Group CEO Brad Saunders explained that his goal in removing the space was to
take the focus off of version numbers and onto a brand name.
“One of the things I’ve trying to signal right now is that we don’t plan
to get into a 4.0, 4.1, 4.2 kind of iterative path,” he told us. “And we
don’t want it to be associated and used with products as a differentiator .
. . we want to keep it as simple as possible.”
The USB 3.x spec has been filled with different version numbers, including
USB 3.0, USB 3.1 Gen 1, USB 3.1 Gen 2 and four different versions of USB 3.2
, in addition to the presence or absence of optional features such as USB PD
and alternate mode. But Saunders told us that those numbers are really for
developers and he wishes that OEMs would use simpler terms like “SuperSpeed
USB” when marketing their products.
Perhaps because of his concern about marketers throwing too many digits at
consumers, Saunders said the organization does not plan to use version
numbers for spec updates. So, even if there’s a faster iteration in two
years, it will likely still be called USB 4 but with the speed number after
(we imagine something like USB 4 80 Gbps). He and his team still haven’t
decided on a branding strategy, so there may also be a marketing name for
USB 4. Much like USB 3.x is known as “SuperSpeed USB,” USB 4 could end up
with its own moniker (we suggest “Super Duper Speed USB”).
“I want it to be a clear distinction. USB 4 is its own architecture with
its own set of speeds and try not get trapped on these dot releases for
every single speed,” he said. “When and if it goes faster, we’ll simply
have the faster version of the certification and the brand.”
Bottom Line
There’s still a lot more that we don’t know about USB 4 than we do. We’ll
learn a lot more when the spec is released later this year, but whatever
happens, don’t expect to see devices with USB 4 until at least late 2020,
but more likely 2021 and beyond.