Leopards Flash Cache Secret
?"> But for Apple, a software feature can also be a hardware feature. Heres my own very circumstantial conjecture to support another rumored Leopard feature. Back in the summer, I wrote about Intels progress on Robson, the companys forthcoming flash cache architecture. Supporting Windows Vistas ReadyDrive and ReadyBoost acceleration technologies, Robson offers an alternative to the use of "hybrid" flash-enabled hard disks and external flash thumb drives. The architecture comprises a flash cache of up to 4GB, a controller ASIC on a PCI Express minicard and driver software on the host computer.There are several advantages that Robson has over the use of thumb drives and hard disk caches for this system acceleration. First, because its placed inside the computer, its considered "safe" and the system trusts its data integrity between sleep states or even shut downs. Vista rebuilds the cache on a thumb drive in between sleeps. This saves time and creates a better user experience. In the case of flash on hard drives, Robson can economically support a larger cache than drive makers might consider. Currently, no hybrid drive is being manufactured, although a couple of companies say they expect to ship product by the end of March. On the other hand, Robson has some downsides for computer vendors. The architecture would add extra cost to PC notebooks in a market that frowns upon extras. And theres currently little perceived value in these caches. Intels control over the flash chips used for Robson implementations may also be a problem for some. In presentations at Junes Flash Memory Summit conference, Knut Grimsrud, director of storage architecture for Intels storage technologies group, said Robson machines would only use Intel NAND flash for QA (quality assurance) reasons. Click here to read more about Vista and hybrid hard drives. Yet for Apple, these points might not be deal breakers. The company is used to including proprietary interfaces or connectors on its hardware, especially for its notebooks. For example, Apples MacBook Pro uses MagSafe, a magnetic power connector that can keep your notebook on the table instead of being pulled down to the floor. In addition, Intel would be seen as a trustworthy partner for this outside technology. The company is Apples technology partner now. Since Robson takes control of the flash management and will use its own home-grown wear-leveling algorithms for the onboard cache, this might be a plus for Apples concerns about QA. Certainly, the inclusion of Robson on Apple systems would bring an improved user experience, something that Apple values. Finally, at the June 2006 conference, Intel representatives kept pointing to June 2007 as the expected arrival date for the Robson technology. Now, that date may have been bandied about because Microsoft at that time was pushing a requirement that mobile systems include a flash cache or hybrid drive in order to receive the highest Vista logo. But that timing also fits well for Mac systems that ship after the release of Leopard. In a ironic touch, Apple could become the first system vendor to ship a machine with an expanded flash cache architecture as standard equipment. Currently, no PC vendor has announced support for Robson or for including a hybrid drive. Of course, neither Apple nor Intel has said anything about Robson on a Mac. Just as we would expect. However, Intels Grimsrud told me last June that there was nothing to prevent Robson technology from being used by other OSes. "Theres no commitment yet for other operating system support based on what customers want," he said. Sounds like a go to me. Next Page: Lessons From a WWDC Past
Read more here about Robson, ReadyBoost and ReadyDrive.