Windows 7 To Break Backwards Compatibility

Everton | May 23, 2008 | Comments

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Previous versions of Windows provided backwards compatibility with older versions of windows, making it easy for users to upgrades as their favorite programs would still work.

However, with Windows 7 Microsoft are approaching backwards compatibility differently, and Windows 7 will not be binary compatible with older versions. This won’t mean that older programs won’t run, but that virtualisation will be used to make them run. The key drivers for this are performance improvements, but also in an attempt to sidestep regulatory programs.

Vista struggles with performance because Microsoft choose to incorporate regulatory challenged features like Internet Explorer and Windows Media Player using a modular design, rather than the monolithic processes used in previous versions of windows. The greater use of componentisation led to performance issues due to the increased number of libraries within the operating system. Simply put, the more separate files your hard drive has to load, the slower your system is going to run.

Another reason why Vista runs so slowly is:

The operating system stores multiple copies of core system libraries, as each revision of a library typically adds/removes functions, and applications compiled with dynamic links to a specific version of a DLL file may call on functions not present in the currently installed library. Vista aims to solve this issue through the WinSxS collection; essentially a massive store of every differing version of libraries present on the system. That way, when an application makes a call for a dynamically linked library, Vista queries the WinSxS cache for the correct version, which is then loaded into memory. On the average system, this directory can be several gigabytes in size, with much of the code duplicated between the separate versions many times.

By not being binary compatible with previous versions of Windows and being built from the ground up, will give Windows 7 significant performance improvements. This will make it easier for developers to produce faster apps as they won’t have to worry about backwards compatibility, but it will increase the upgrade pain for users who may find that some of their existing applications will no longer work and will need upgrading.

Where do you lie on the trade-off between compatibility and speed? Do you think Microsoft are making a mistake here?

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About the Author: Everton is based in London and has worked in the internet and mobile space for over ten years now, and before that worked in corporate strategy and consulting. He has a degree in Economics from Cambridge University, and currently runs the Portal and online operations for one of the largest ISPs in the UK.He also writes for Windows 8 News, Connected Internet and One Tip A Day.

  • Windows in its current, bogged-down state sucks bad enough as it is, that it might not be a bad thing that people will have to get rid of everything-Windows that they already own to start fresh with Win7. But unless we're coming up to a major hardware curve that'll be happening right around the time of Win7's release and computers suddenly get significantly better than they are now and people have a decent incentive to upgrade, and unless application writers actually begin porting their programs to Win7 and many of them are ready in time for release, then people are probably not going to buy it. It's a gamble, but I think it could really pay off for Microsoft if they get their part right and get the SDK out to developers well ahead of time.
  • jimw7
    You dummy, in the days of DOS programs were efficient, it's modern programmers who don't know how to program efficiently that require more memory to run their junk. There were some very efficient business applications written in dbase 3+.
  • lefthandpisces
    That's true. The first mission to the moon ran on computer software that could fit on a floppy disk (about 2 MB). It included rocket fuel calculations, memory management, trajectory correction, and hundreds of other features.

    Programmer didn't have much to work with back in the day so they had to write very efficient code. Nowadays memory isn't a problem, so sloppy code persists in several mainstream software
  • amj2008
    it won't happen, that's my opnion, because mikeysoft won't kill the hen that lays golden eggs...(the business wolrd)
  • Matej
    If the backward compatibility is about to be broken then it is also time to make one more step forward and also brak free from propriatery software and start switching to free and open source operating systems.  Switching to Linux would also be less risky as it already exists, is already well tried and tested, has lots of software already and thus the switch would probably be faster than the switch to Windows 7. Not to mention all the advantages athat a truly open and free (both as in freedom and no cost) platform like Linux provides to the consumer. if we have to do the switch/port we might as well do it properly and completely.
  • Avatar
    @Jesse, Windows core is not big at all and will fit in very little ram, But after adding all the gui etc it becomes heavy

    Developers won't have the SDK before it's release that's a fact, They may release it like a few months before so they can start *cough* Vista */cough*

    Buy I for one can for see many problems with breaking the backward compatibilty, Busineses will have a hard time as they have to but all new software or try and hope the emulation will work and their app doesn't break,
    The general user (like all those who use Windows cause it was preinstalled) wouldn't really care as all they want is a system that works (efficently or not)

    If Windows Seven does break the Windows platform then I for one will be switching completely to *nix/gnu based OS's
  • Florent L
    As a power user (and profesionnal uses) , my easy answer is : performance/speed is better than compatibility!
    Yes, that represents a cost. But it will be compensated by the time-saver obtained. Moreover, I think that this will take part in a better stability.
  • James
    I have to say that Vista is tantamount to Windows ME (Mistake Edition).  It's almost like Microsoft intentionally screwed up with Vista so that they could make the business community more willing to go for anything, and hope it turns out to be like XP where it was 10 times more stable and useable.
       I don't have any real issue with breaking backwards compatibility, IMO it's the bloat of the "integration" of unnecessary components, like Media player and copywrite protection, into the "Operating System" that cause the larger amount of slowdown.  If breaking compatibility with older systems is necessary to make a less bloated, faster, and more user friendly system, I say lets do it!!!  But I agree with several on here that if that's the case, why not take a look at Linux/BSD systems that are free, and significantly more stable already. Heck, if nothing else, a Linux system will cut down on the need for a "better system" to run it, given that many linux distributions run just as well on older machines, unlike ANY of the latest and greatest Windows offerings, which ALWAYS require more power than the last version.
  • jabberwolf
    Simple option that I hope MS incorporates.

    Allow a VIRTUAL version of Vista/XP that allows installing of older programs. This should keep the installs and everything else out of Windows 7. Have an "import feature, that allows this for people with older computers, and have them convert their older PC into a virtual one.

    Virtual machines are all the rage and I dont see this slowing down. And as storage gets cheaper and larger this would be a great option for Microsoft to provide.

    This might also help them once and for all get some attention away from VMWARE and on MS's virtual ideas.
  • Mike
    Windows versions when they've first come out have been slow and have required more HP(horsepower) and hardware has to catch up, its taken 5 years for xp to become a fast OS. Linux however runs on everything fast period! I personally think a re-write from the ground up is excellent but will cost them their large sales at the start but like auto updates and OEMS people are gonna end up with stuff they dont like weather they like it or not. you buy a new pc.. im sorry you get MS shovelled down your throat. Mac sales will increase and many will stay on vista and xp for a few years till software is available to suit. I think its about time to email/lobby to software giants like adobe to make Linux software, wouldnt take much to switch the mac versions to linux.
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