Sponsored Link •
This article attempts to explain not how Jini works, but why it exists. It illuminates on the unique value of Jini technology, reports on the recent Jini Community Summit, and considers Bill Joy's comments on his creation.
I first read about Jini last summer in an article in the San Jose Mercury News. In the year since then, I've struggled not only to come up to speed on the technology, but also to understand its implications. Fortunately, I've had the opportunity to collect insights from many of the people at Sun who shaped the technology. In this article, I'll tell you what I learned, based mainly on my discussion about Jini with Bill Joy at the recent Jini Community Summit and on my interview with James Gosling prior to the 1999 JavaOne Developer Conference.
Another hardware revolution on the horizon?
On May 19, I flew to Aspen, CO, to attend the first Jini Community Summit. I went to Aspen to learn more about Jini, to see what other people are doing with it, and to attempt to figure out what the Jini community is all about. The first person I met was Torin Sarasas, with whom I had agreed over e-mail to share the expenses of a hotel room. At 6:30 that evening, Torin and I walked over to the community center for an informal cocktail reception. Being rather hungry, I dragged Torin over to a table of cheese, crackers, and vegetables, where I filled up a plate. Then we set out to mingle.
We wandered from group to group, mingling with people and conversing on a variety of topics. One topic that seemed to come up again and again was the rumor that a wireless network of some kind blanketed all of Aspen. I had heard this somewhere before, but I didn't know any details. No one in the groups I landed in seemed to know anything concrete either, but at one point I looked over and recognized somebody who probably would know. "Hey, that's Bill Joy over there," I said to Torin, who said, "Wow." Both Torin and I have always held the utmost respect for Joy because of the high caliber of his technical creations. For a few moments, we both stood and looked at him in awe. Then we rejoined the conversation of our group of people.
Joy was also in a mingling mood, and before long he walked over to our little circle of people. He didn't seem to know anyone in our group, so to get the conversation going, I asked him about the Aspen wireless network rumor. He confirmed the network's existence, informing us that it in fact reaches all the way down to the border of Utah. Even though the wireless network covers about 100 square miles, he told us, it actually consists of a single class C Ethernet network. Joy added that the wireless network works very well, and predicted that every major city will have something like it by 2007. So the rumor was true.
Later that evening, a Jini Community Summit attendee informed me he had checked his e-mail on a small device connected to the Internet via this wireless network. I walked outside onto the patio and located the device and its owner. The gadget in question, which was sitting in the middle of a table on the patio, was a small PC with a tiny keyboard, a tiny screen, and what appeared to be a PCMCIA network card sticking out of its side. I was granted permission to use it, so I leaned over this small PC, fired up telnet to connect to my ISP, ran pine, and read and replied to my e-mail.
Chips and bandwidth
As I worked through my e-mail on the small device, I had a strong sense that my simple act offered a glimpse of things to come. Two emerging hardware trends were to some extent already represented on that patio: the proliferation of small embedded devices -- anything with a microprocessor embedded in it that has a relatively focused functionality -- and the proliferation of high-speed, ubiquitous networks. I was impressed by two things as I checked my e-mail that day: the speed of Aspen's wireless Internet connection, and the complete lack of any wires or cords leading to the PC on the table. The device didn't contain a power cord or network cable. Checking my e-mail involved only me, the device, the electromagnetic spectrum, and a nice view of the mountains.
Examples of embedded devices include cell phones, microwave ovens, VCRs, pagers, clocks, and printers. Although a PC contains an embedded microprocessor, it isn't usually considered an embedded device because it doesn't have a focused functionality. Rather, a PC is a general platform suitable for running many kinds of software. A microprocessor-enhanced typewriter is an embedded device, focused on the job of typing. A PC running a word processor can serve the same purpose as the typewriter, but the PC doesn't qualify as an embedded device because that same PC could be used to run a spreadsheet, surf the Web, or play solitaire.
System on a chip
The proliferation of embedded devices is being driven by the decreasing costs of adding processing power to devices, which is a result of increasing the functionality of the chips -- or chip -- embedded in a system. The morning following the cocktail reception, Bill Joy gave a presentation called "The Jini Vision." During this presentation, Joy said that the personal computer revolution was spawned when Steve Wozniak, cofounder of Apple, fit everything for a computer onto a single motherboard. The single-motherboard computer, a simple but fundamental change in the hardware status quo, made it less expensive to build computers. These days, Joy continued, entire computers can be placed onto a single chip, which he called "systems on a chip." Putting an entire device on a chip, he said, makes the device cheap and reliable. At that point a fellow sitting in the audience, Bruce Christopher, mentioned that his company, a startup called JCan, is doing exactly what Bill Joy was describing. JCan is developing a chip based on Sun's picoJava core that will include the Java and Jini APIs on the chip. Christopher said he hopes to get the cost of his chip, which he called a "silicon motherboard," down to $10 in five years.
As both the cost and size of computers continue to decrease, it becomes cost-effective to include processors in more and more kinds of products. To add value to their products, manufacturers will be enhancing them with embedded processors. In the coming years, this trend will yield an explosion of embedded devices.
Connecting to high-speed networks
The other trend underway in the hardware world is the proliferation of high-speed networks. Companies are basically tripping over themselves to build this infrastructure, spending billions of dollars along the way. High-speed backbones are being built. High-bandwidth pipes are being sent into homes. Wireless networks are being developed. Increasingly over the next decade, the network will be fast, and the network will be everywhere.
The current trends in the hardware world point to a future in which more and more devices that we use every day will be enhanced with embedded processors and interconnected via networks. Over time, our environment will become "smarter," and this promises to bring profound changes in how we do things at work, at home, and everywhere else.