With IE8, Microsoft is attempting to solve one of the most annoying problems with today's multi-window, multi-tab browsers; namely, the disastrous effect that a browser crash has. It is an unfortunate feature of most browsers that a crash in one tab takes down the whole browser instance. Whether the cause is a bug in the browser itself, a malicious script, or a badly-written plug-in, the effect is the same; not only does the tab that caused the problem disappear, so does the tab with your half-composed forum post, the train timetable you need to get home, and the audio stream you're listening to.
IE8 tackles this by separating each tab into its own process, a feature it calls "Loosely Coupled IE." Starting IE8 actually creates two processes; one process for the window frame, address bar, toolbar, and tab bar, and a second process for the tab itself. Subsequent tabs may also open in new processes. Running a tab in its own process allows that tab to crash (for any reason) without disrupting any other tab. This feature was present in Beta 1; in Beta 2, Microsoft has worked to reduce the overhead it causes and improve its performance. For example, now the processes creating the window frames are merged, so starting IE several times will only create new tabs in the existing frame.
The ratio between tabs and processes is not exactly 1:1; although this provides the most isolation, the ratio of processes to tabs will depend on machine capabilities. This process separation also resolves a major annoyance in IE in Windows Vista. In Vista, sites in different zones cannot be open in the same IE window. A file opened from the hard disk cannot coexist with a file opened from the Internet; instead, two different IE processes are required, one for each security zone. Because IE8 uses different processes for each tab, this restriction is lifted; different security zones will still use different processes behind the scenes, but they will be able to share the same window.
The final piece of the puzzle is Automatic Crash Recovery. As with LCIE, this was present in Beta 1, but has been improved for Beta 2. ACR is designed to improve the experience when the the inevitable occurs and a tab crashes. Instead of losing everything you were doing in the tab, ACR restarts the process and restores the tab's context—in Beta 1, this meant it opened the same URL and kept the back/forward browser history.
ACR had promise in Beta 1; however, it neglected to recover the most important things—text entered into forms, and session cookies. Without these, the experience is a little frustratring; the browser reopens the right page, but you find yourself logged out and with your half-written e-mail gone. Beta 2 fixes this by recovering both form data and session cookies. This means that Beta 2 will be able to put you right back where you were before the tab crashed, with virtually no interruption.
As well as being incomplete, ACR in Beta 1 was not itself particularly reliable; it was easy to make the browser get into a never-ending cycle of crashing, restarting, recovering, and then immediately crashing (because the URL being recovered caused the crash in the first place). Microsoft has not said anything about whether this will continue to be a problem.
Of course, while better handling of crashes is no bad thing, it would be even better for the browser not to crash in the first place. Microsoft has long had an (opt-in) system for reporting crashes and hangs back to the company—Windows Error Reporting (aka, Watson). This data allows the company to locate bugs and determine which are in need of the most attention. On the blog, the IE team stated that they have committed to fixing the top 50 percent of all the Watson errors they have; this should provide a significant boost to reliability.
When IE8 is released later this year it will undoubtably be the best version of Internet Explorer ever. IE's competition is improving all the time, and gaining in popularity, and—at least when it comes to standards compliance—is already superior today to what IE8 will deliver later in the year. Microsoft's uphill battle to stop the rot and turn IE around is far from over.
Source :
ArsTechnica
Its a bit old news (before the launch of IE 8 Beta 2) but i thought its worth sharing. Also these features are more visible in Beta 2 then they were in Beta 1. And Yes, ACR has definately been improved in Beta 2. i am runnin IE 8 contineously for last 2 days and seen just a single crash in a single tab today which when i tried to dig deeper, was caused by the integration DLL of Free Download manager. I have, ofcourse, reported it to FDM team.
IE 8's Crash Recovery and Performance Improvement Features
Re: IE 8's Crash Recovery and Performance Improvement Features
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