Saturday, March 03, 2007

Mobilizing Mobiles

Ah, the power of blog! You publish a simple idea, and back comes real gold. My thanks to eric and xiris for their comments, and for pointing out that much of what I "predicted" in my last post about mobiles replacing desktops has already happened! Nokia have already ported the Apache web server to run under the Symbian operating system which many of their phones use, and they have built "cgi scripts" that expose much of the phone's data (messages, address lists, images captured) to any browser that connects to the phone's IP address and (I guess) authenticates itself. So if you leave your phone at home by mistake, you can browse it from the office, check for messages and reply to them, check for missed calls, and so forth. Very clever! Of course this requires each phone to have a distinct IP address, and there aren't enough to go around, but IP Version 6 is gradually getting implemented and that will over time give us more than enough addresses.

Eric points out that much of what I "predicted" happening on mobiles is already available on PDAs such as the Nokia Tablets.

Xiris is concerned about the lack of storage space on mobiles. Storage size has been growing a lot faster than Moore's law, but so has our appetite for using it. Three years from now, mobiles might offer 20Gbytes of storage, and we'll be demanding terabytes. The good news is, we don't need all of our data all of the time – our attention span is simply too limited. Our mobiles' storage can operate as a level one cache, with the bulk of our files residing on a file server somewhere in cyberspace. We'll be able to search an index of all of our files, and choose the one we want. If it isn't already in our mobile, it will fetch it for us. And once the mobile's storage starts getting full, it will upload some files that we haven't used for a while and free up the space that they were using.

Worried about how long the download will take? HSUPA will soon offer better than 4Mbps downloads to our mobiles, and of that isn't fast enough, HSOPA will offer us up to 100Mbps.

Worried about who's going to store all your files and maintain an index across them, and deliver them to you when you need them, and how much it will cost? At the rate they're going, Google will probably do all this for free, unless you beat them off with a stick. Other folk will surely be happy to do it for money.

Xiris is also concerned about the lack of processor power in mobiles. They typically have a 200MHz 32 bit processor today, some have 400MHz, and they're "only" improving at the rate of Moore's law. If you want to to do serious spreadsheeting, for example, how responsive will your mobile be? And how much power would it gobble, running the battery down? Xiris also suggests the answer – to embed a utility processor in the docking station, which is a fixture and which can draw line power, and to offload some of the processing workload onto this processor while you're docked. This is a very realistic approach. The dinky screen size of the mobile is going to limit how much serious processing you do with it. If you need to crunch a serious spreadsheet, or update a large document, you will probably seek out a docking station for its big screen and keyboard if nothing else, and get the use of its processor at the same time.

So how can we offload processing onto the docking station? Let's get back to the way in which we deliver the mobile's applications to the docking station. I suggested that we should web-enable them, so that the user can use a browser on the docking station to view and drive the mobile's applications. But think about it – do we really want to code every mobile application twice, once to run on the mobile itself and a second time to run in a browser in a docking station? Life is too short, programmers too scarce (I know, I am one, and I can't get around to programming all the stuff that I want for myself). So let's assume that the mobile's applications are delivered in the same way to either its own screen or to a docking station – as a web app. Most modern mobiles have browsers built into them. Many only support the WAP or WML subsets of HTML, which doesn't include JavaScript, but a fair number of mobile browsers can handle JavaScript, and this number is increasing as the amount of memory available for phone apps grows.

So let's assume that the mobile of the future delivers its applications to a browser in much the same way that Google delivers its Docs and Spreadsheets applications, whether to a docking station or to its own screen. A lot of the processing now takes place in the browser instead of on the web server, courtesy of some clever JavaScript code. And the JavaScript code in Google's spreadsheet web app isn't nearly as smart as it could get. Currently, it sends every cell that you change to the web server via AJAX so that the server can decide how to format the cell's content, and update any formulae that might depend on that cell's value. Most times we change a cell, it's to write in a simple number or character string. It would not be hard to write JavaScript to check whether this is the case, and to format the cell accordingly. Nor would it be hard to check whether any formula includes the changed cell in its scope; if not, there's no need to recalculate the formula. Nor would it be hard to check if the user had previously specified a particular format for the cell that has changed, or a range of cells that includes the changed cell, and to apply the appropriate format. Nor would it be very hard to implement many of the functions that spreadsheets offer, and especially the ones most often used, in JavaScript code, so that any changes to the cells in their scope could be calculated in JavaScript in the browser. Only the way-out and weird cases would have to be sent up to the server, and that would be rare. The browser would handle the regular stuff on its own, offloading the server.

I have had a look at the HTML page that implements Google spreadsheets. It includes about 380KB of JavaScript code, most of which has had the comments and white space stripped out. When JavaScript is downloaded to a browser, it will be zip-compressed if both web server and browser support zip, which most do. That would bring the JavaScript download down to about 125KB. On a dedicated 1Mbps link, this would take about a second. That's about as long as it takes to open a spreadsheet package on my current laptop. And almost all browsers cache the files that they download, so if you get into the spreadsheet application several times in a day, your browser would only need to download the JavaScript code once – unless it ran short of buffer space and needed to prune its buffer.

Likewise when users of http://blogger.com like me :) use its posting page to write up and format a new post, clever JavaScript code in the posting page handles all our text input, editing, and formatting instructions in the browser, only involving the server once we have completed the document preparation. I have just had a look at the posting page. It includes about 23 JavaScript files and has a small amount of JavaScript embedded within it. In total, it uses less than 234KB of JavaScript code to implement what is a pretty handy document composition and editing facility. Most of the JavaScript files still have their comments and white space intact, for readability. There are utilities that can strip out comments and white space and spit out just the code that does the useful work. With zip-compression, the JavaScript download would be less than 60KB. On a dedicated 1Mbps link, this would take half a second. That' a lot quicker than opening your average word processor. And JavaScript file buffering wold help here too.

In short, we could offload most of the spreadsheet and document processing overheads onto the browser, reducing the load on the web server and the network at the same time. If the web server is running on your mobile and the spreadsheet or document processing is taking place in a browser on a docking station, then the processor in the docking station will be doing most of the work. So you wouldn't need a very fast processor in your mobile, nor would you burn up its battery while you do these tasks.

On the other hand, if you're on the road and only have your mobile to access one of the documents or spreadsheets on it and maybe make a few changes, then the browser and JavaScript will run on your mobile. Your processing rates will not be great, and you will burn your battery while you're busy, but at least it's possible. The constraints of your mobile's screen and keyboard will probably keep this mode of operation to a minimum, but it would be nice to know that when you really need to do it, you can.

The JavaScript language was developed originally by one man, Brendan Eich, rather than a committee. It was loosely based on the Java computer language. It's a much smaller, simpler language, and is not gaining features and fat as quickly as is Java, which has locked horns with .NET's C# in a sequel to the browser wars movie. Folk who know JavaScript well find it really elegant and powerful. It's not the language that anyone would make their first choice for coding a spreadsheet or document processor, but it's there in almost all browsers. As Woody Allen once said, 80 percent of success is just showing up, and JavaScript is showing up much more than any other in-browser language. Its biggest current drawback is that it's an interpretive language, and runs slower than a compiled language. But then, Java and C# are also inherently interpretive languages. Maybe it's time the open source community started working on a Just In Time compiler for JavaScript. Because of the small size of the language, it wouldn't be very hard to do.

By the way, I don't hold any stock in Google, but after researching for this post ... hmm.

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