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Microsoft's JavaScript Engine Gets Two-Tiered Compilation
jones_supa writes: The Internet Explorer team at Microsoft recently detailed changes to the JavaScript engine coming in Windows 10. A significant change is the addition of a new tier in the Just-in-Time (JIT) compiler. In Windows 10, the Chakra JS engine now includes a second JIT compiler that bridges the gap between slow, interpreted code and fast, optimized code. It uses this middle-tier compiler, called Simple JIT, as a "good enough" layer that can move execution away from the interpreter quicker than the Full JIT can. Microsoft claims that the changes will allow certain workloads to "run up to 30% faster". The move to a two-tiered JIT compiler structure mirrors what other browsers have done. SpiderMonkey, the JavaScript engine in Firefox, has an interpreter and two compilers: Baseline and IonMonkey. In Google Chrome, the V8 JavaScript engine is also a two-tiered system. It does not use an interpreter, but compiles on a discrete background thread.
Why IE7? IE9 is the highest version of IE that will run on Vista, which is the lowest currently supported version of Windows.
For node.js and/or .NET apps on Windows?
It'd seem like a waste of effort if the shiny JS engine can only be used within IE. IE is dying anyway and they could save tons of money by embedding WebKit instead.
Even many very large e-commerce sites dropped IE7 now, as it accounts for a very small amount of sessions, and an even smaller amount of conversion. Software engineers are expensive, and you need a lot to maintain a moderately complex website/app that supports IE7.
IE8 is a little more awkward. If your target audience is the general public (again, ecommerce site selling stuff to a general audience), you'll have to support it. If, however, you have a more sophisticated product (let say you target a more professional user base), you generally can get away with only supporting IE9 and up (ie: thats what Amazon EC2 does i beleive).
And if you develop an actual specialized web "app" that you license to a small group, something that will only be used internally by a few users, let say an HR management software or an ERP, you can have pretty constrained supported browser lists. This is where you can start wiping out the "Firefox/Chrome edge or IE10+". Developing with only green browsers as targets is pretty nuts. Lots of features you've never thought about become available. You can have offline mode because of local storage, webGL can be assumed, performance is rarely an issue, you pretty much don't need librairies like underscore anymore to do functional stuff because Array.prototype has most of it...
Fun stuff.
I can see this going the same way as number of shaving blades on a razor with 5 tiered JIT js.
Great minds think alike; fools seldom differ.
Safari offers *four* tiers with their FTL (Fourth Tier LLVM). Lots of detail here: https://www.webkit.org/blog/33....
Of course, our HR and ERP systems took the exact opposite approach. They only support IE6.5 through IE8, or Firefox 14 - 19. Of course, they also force us to have Java 1.6 still installed because while their app runs on Java 1.7 and 1.8, they do some version checking and artificially block it.
Vista, which is the lowest currently supported version of Windows.
That's actually not true, strictly speaking... XP is still supported, for those (usually governments and large companies) who are willing to pay Microsoft for it...
Need to type accents and special characters in Windows? Use FrKeys
Would you rather they didn't? You'd get to be smug either way, it seems.
You say it dismissively, but the big thing lately is that Microsoft can play catch-up and is really trying to do it. Did you ever think you'd see the day? Starting around MSIE 9 they made huge strides toward becoming fairly normal, rather remaining forever obsolete, as a weird, special, anachronistic case. You never would have heard anyone say this in 2009 or 2004 but it now looks like a fresh Windows install might be able to surf the web, right out-of-the-box.
It used to be that if someone had problems and you found out their browser was .. well, they didn't know, but they said they just "clicked the internet" .. you'd tell 'em they need to get a browser, any reasonably modern browser. But I rebooted to do some testing just yesterday, and MSIE 11 does not suck. Seriously, I found more problems with Safari on Windows, than I did with MSIE.
Today's web browsers, in general, are pretty damn good. Even Microsoft can do this now.
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The Windows version of Safari has not be updated in forever (browser time), you can probably drop "Safari Windows" from your testing list.
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