Ten things to know about Intel's Thunderbolt

 

 

Intel and Apple sent quite a shock wave through the PC and consumer electronics communities today with the launch of Thunderbolt, a high-end interconnect that leapfrogs both Firewire and USB 3.0.

 

Plenty of questions remain unanswered. But Intel has shed light on some of the major issues. Here's the EE Times FAQ on Thunderbolt.

 

1. When will a full spec be openly available?

 

Intel is so far only sharing full technical specs of Thunderbolt under non-disclosure with partners making Thunderbolt products. It plans to release a developer's kit before July that will include technical specifications for Thunderbolt. However, it currently has no plans to publish details of the spec online.

 

2. What is Thunderbolt?

 

Thunderbolt is new interconnect from Intel first available on new Apple MacBook Pro notebooks. It supports two 10 Gbits/s bi-directional channels on a common transport for 40 Gbits's max aggregate throughput. PCI Express and DisplayPort protocols are supported on top of that transport.

 

3. What are the applications for Thunderbolt?

 

Intel defines several of them.

 

Thunderbolt can be used to create flexible system designs. For instance, thin notebooks or clients can use Thunderbolt to link to high-end drives, displays and other external devices instead of building them all into one box. Essentially, it provides a PCI Express link outside the box.

 

The interface will be used to quickly send big files between PCs, cameras and drives. It will also be used with DisplayPort as a link to displays.

 

4. Will Thunderbolt kill USB?

 

No, Intel will continue to support USB and will integrate the next-generation USB 3.0 technology in its future PC chip sets. Intel sees Thunderbolt and USB as complementary, generally addressing different applications.

 

However, Intel does admit USB 3.0 and Thunderbolt will overlap in some applications, particularly in storage. Several chip makers have introduced products supporting USB 3.0 to SATA for external storage arrays.

 

"We expect [use of both USB 3.0 and Thunderbolt] will enable various price/performance models and choices for consumers," said Jason Ziller, director of Thunderbolt planning and marketing at Intel.

 

If Thunderbolt takes off it could blunt the growth trajectory for USB. But USB is used so broadly it will continue to be supported and grow for a very, very long time.

 

5. Who will supply silicon for Thunderbolt?

 

Only Intel for the foreseeable future.

 

Intel is supplying a Thunderbolt controller and is not commenting on whether it will open up the spec for others to make similar chips. Details of the controller are currently not available, leaving open questions about its price, size, power consumption and whether separate host and peripheral controller designs are required.

 

6. Will Thunderbolt support optical cables?

 

Currently it is only available for copper cables supporting distances up to three meters. Intel said it is still doing R&D work on an optical version which will be made available eventually, but that could be a few years away.

 

Like Thunderbolt itself, the full details are not available for the unique copper cable it uses.

 

7. Wasn't Thunderbolt supposed to support optical cables?

 

Yes, initially Intel announced the technology in September 2009 under the name Light Peak as an optical system-to-system link. However, that changed according to Aviel Yogev, director of Thunderbolt engineering at Intel.

 

"OEMs told us that until vendors can reduce the cost of optics significantly they have difficulties adopting that technology," Yogev said. "At some point we need to move to optical, but for the next few years it will be electrical [i.e. on copper cables]," he said.

 

"We haven't abandoned an optical connection," he added. "Optics is in our future and will be needed over time, so we are still doing R&D in that area and assessing when the time is right," he said.

 

8. What's the roadmap for Thunderbolt?

 

This too is unclear. Intel suggested it will support terabit/second throughput by 2013. It could do that by increasing the number of 10 Gbit/s lanes or increasing lane speed. Intel said it will eventually support optical cables which could bolster bandwidth and support distances of tens of meters.

 

9. Who is supporting Thunderbolt?

 

Apple struck a deal from Intel to be the first OEM to use it in a host system, the new MacBook Pro notebooks. It is not clear which OEMs, if any, will support the interface.

 

Several peripheral makers said they will support Thunderbolt. They include Aja, Apogee, Avid, Blackmagic, LaCie, Promise and Western Digital. So far only two of those companies are demonstrating working products and none have released details about what products they will ship, when and at what prices.

 

Missing from this list are any semiconductor vendors, top drive makers such as Seagate, Hitachi GST and Toshiba and any other PC makers.

 

10. How will Thunderbolt avoid the problems of Firewire?

 

This is perhaps the biggest unanswered question. Years ago, Firewire appeared to be a shoe-in as the high-end computer and consumer interface. It had broad backing from chip and systems companies and was way ahead of USB is throughput and latency.

 

Ironically, Apple was one of the companies that took the lead building Firewire into its systems, courting its users in publishing and media creation.

 

But Firewire proponents rolled out a somewhat long and confusing roadmap, leaving some to question whether they wanted to support the interface right away or wait for a future generation. Meanwhile, USB made steady progress getting design wins and regularly updating its speeds, closing the gap with Firewire.

 

USB 3.0 was poised to leapfrog Firewire which has lost broad backing until Thunderbolt struck.