This is an excerpt from the first chapter of SAP HANA Essentials book which will be released at Sapphire NOW Orlando in May, 2012. This section is part of the conceptual discussion of the shift from disk-based to in-memory data storage and retrieval.
There’s another fundamental law of the technology industry: Faster, Better, Cheaper. That is, each new generation of product or technology has to be faster, better and cheaper than the generation it is replacing or customers won’t buy it. Geoffrey Moore has some great thoughts on how game-changing technologies “cross the chasm” and faster, better, cheaper are fundamental characteristics that must be present for a successful product introduction.
In-memory computing perfectly fits the faster, better, cheaper model. RAM memory is hundreds to thousands of times faster I/O than disks, so there’s really no comparison in how much faster you can get memory off of a database in RAM than a database on disk. In-memory databases are better architecture due to their simplicity, tighter integration with the apps, hybrid row/column store and ease of operations. When you compare the cost of an in-memory database versus a disk-based database on the right metric – cost per gigabyte per second – they’re actually cheaper. Also, when you compare TCO of in-memory databases, they’re even more economical to operate than traditional databases.
But faster, better, cheaper has an even more important role than just looking at the technology. If you really look at what the switch from an “old” platform to a “new” platform can do for overall usability of the solutions on top of the platform, there are some amazing possibilities.
Take the ubiquitous iPod for example. When Apple introduced the iPod in 2001, it revolutionized the way that people listened to music, even though it certainly wasn’t the first MP3 player on the market. The key innovation was that Apple was able to fit a tiny 1.8 inch hard drive into its small case so you could carry 5gb of music in your pocket, at a time when most other MP3 players could hold ~64mb of music in flash memory (“changing the rules of the game”). I/O speed (input/output) wasn’t a terribly big concern to play MP3s, so the cost per megabyte per second calculation wasn’t terribly relevant. By that measure, 5gb of disk for roughly the same price as 64mb of RAM was a huge difference. It wasn’t significantly faster than its competitors, but it was so phenomenally better and cheaper per megabyte (even at $399) that it became a category killer.
However, in hindsight, Apple had to make quite a few architectural compromises to squeeze that hard drive into the iPod. First, the hard drive took up most of the case, so there was very little room for anything else. There was a tiny monochrome display, a clunky mechanical “click wheel” user interface, a fairly weak processor and most importantly, pretty short battery life. The physics needed to spin a hard disk drained the battery dry pretty quickly, but the iPod experience was still so much better than anything else out there it soon took over the market.
Fast forward six years and Apple was selling millions and millions of the 160gb version of the “classic” iPod with 32 times more storage than the original model—at the same price as the original 5gb model. They had added a color screen and a pressure-sensitive “click wheel”, but the latest model was significantly similar to the original in most ways. But now, Moore’s Law had been working for four full cycles and 16gb of memory was about the same price as a 160gb hard drive. Suddenly, the storage capacity of the hard drive wasn’t that big of a deal anymore, hard drives had gotten so big that nobody had enough music to fill it with. In 2001, people had been thrilled with 5gb of storage, basically their entire CD collection fit on the iPod. In 2007, Apple could build an iPod with 16gb of RAM storage (10x less than the current hard drive model) for the same price as the 2001 model.
It’s that shift to solid-state memory as the storage medium for iPods that really changed the game for Apple. Removing the hard drive had a huge impact on their design parameters. First, by getting rid of the disk, they could shrink the thickness of the iPod and reduce the weight. Second, getting rid of the disk meant they had more room in the case for a bigger motherboard and a larger display. In fact, they could now turn the entire front of the device into a display and make the display a touch-screen interface (simplifying the design even further). Now that they had a bigger motherboard, they could put a larger, more powerful processor in the device. But most impressively, by getting rid of the physical hard drive and its spinning disks, they could more than double the battery life.
Now, instead of a music player, they had a miniature computer that you could carry in your pocket. It had an operating system, long battery life, audio and video capabilities and a sufficient amount of storage. Oh, and they could build another model with nearly all of the same parts that could also make phone calls.
Apple iPod model comparison.
Source: Apple Inc.
Once you have people carrying around a computer in their pocket, it only makes sense that developers would build new applications to exploit the capabilities of the new platform. It’s obvious that Apple couldn’t have predicted the success of games like “Angry Birds”, but they did know that innovation couldn’t be unleashed on their new platform until they removed the single biggest piece of the architecture that was imposing all the constraints. Ironically, it’s the same piece of technology that made the original iPod so successful. Think about that for a second: Apple had to eliminate the key feature of the iPod that had made them so successful in order to move to the next level of success with the iPod Touch and iPhone. Not a bad choice in retrospect, but at the time, it was a big leap of faith to take.
In essence, getting rid of the hard drive in the iPods was the most critical technology decision Apple made to deliver the iPod Touch, iPhone and eventually the iPad. Most of the other pieces of technology in the architecture improved as expected over the years. But the real game-changer was the switch from disk to memory. That single decision freed Apple to innovate without constraints and allowed them to change the rules of the game again, back to the memory-as-storage paradigm that the portable music player market had started with.
SAP believes that SAP HANA is a similar architectural shift for its application platform. By getting rid of the disk-based database underneath SAP applications, customers will have a faster, better and cheaper architecture for the future. SAP also believes that this new architecture will have a similar effect on the development of a new breed of business applications that are built natively to take advantage of this new platform.
Note: as of early 2012, Apple still makes and sells the “classic” iPod (160gb/$249), but it is a tiny fraction of their overall iPod sales. So, somebody must be buying the “old” iPods and Apple must be making some money off of them, but do you know anyone who’s bought a hard-drive based iPod in the last five years? You’d have to really need all that storage to give up all the features of the iPod touch.
SAP thinks that there will also be a small category of its customer who will continue to want the “old” architecture- so they’ll continue to support that option, but they’re predicting a similar adoption trend once the SAP Business Suite is supported on SAP HANA. At that point, you’ll need an overwhelmingly compelling business reason to forego all the goodness of the new architecture and renovated SAP apps on top of SAP HANA.