I'm trying to win a bet

October 23, 2009 11:30 PM

Is Windows 7 an upgraded version of Vista (like Snow Leopard presumably is of Leopard) or completely re-built from the bottom up?
posted by metacort to Computers & Internet (19 answers total)

Best answer: Under the Hood, Windows 7 is Vista's Twin (PC World)
posted by rokusan at 11:37 PM on October 23, 2009

Oh, and Windows 7 review: 'New' OS is just Vista with small changes' (Washington Tech)

You can probably find your arguments in there somewhere.
posted by rokusan at 11:39 PM on October 23, 2009

It's an upgraded version. Vista contains over 50 million lines of code; it would be impossible and impractical to throw that away and start from scratch.
posted by lunchbox at 11:40 PM on October 23, 2009

No, it's based on Vista.

Microsoft has only rewritten their OS once, in 1993. That was Windows NT, and it took a decade for it to fully replace their older technology.

Dos -> Windows 3.1 -> Windows 95 -> Windows 98 -> Windows ME -> trash can
NT 3.1 -> NT 3.5 -> NT 4 -> Windows 2000 -> Windows XP -> Windows Vista -> Windows 7

For comparison, Apple rewrote their OS back in 2001 with OSX Cheetah, and have been making incremental changes since then.
posted by aubilenon at 11:42 PM on October 23, 2009 [6 favorites]

As much as MS might like you to forget about Vista, it's an upgrade. While I can't claim any special insight into MS's development practices, it would be insane to rewrite an established OS from scratch while maintaining backwards compatibility with previous releases.
posted by scatter gather at 11:44 PM on October 23, 2009

While it is true that it is an upgrade in the most technical sense, performance-wise it is very streamlined. There were a LOT of bloat issues with Vista and Windows 7 looks to address many of those.

I've heard the experience described as "scaled-back" and "bare-bones" if that helps at all.
posted by Elminster24 at 12:13 AM on October 24, 2009 [1 favorite]

aubilenon wrote on this, but it's important enough that it's worth mentioning twice. The software family you are asking about is Windows NT (I don't know if MS's own site network has any decent history of NT). They've been working on this software since 1989 and have been releasing it for public use since 1993 starting with NT 3.1.

Windows 7, being NT 6.1, it is without a doubt "upgraded Vista". Vista was NT 6.0; XP was 5.1 and 5.2.
posted by asciident at 12:24 AM on October 24, 2009 [1 favorite]

Farhad Manjoo loves it.
posted by ActingTheGoat at 12:48 AM on October 24, 2009

As others pointed out, Vista was an upgraded version of XP, which was in turn an upgraded version of 2000. Windows 7 is basically a 'very refined' version of vista with (in theory) all the bugs and annoyances like the incessant security queries reduced as much as possible.

If you're happy with Vista, there's probably no reason to upgrade.
posted by delmoi at 1:50 AM on October 24, 2009

Dos -> Windows 3.1 -> Windows 95 -> Windows 98 -> Windows ME -> trash can

Dos, Windows 1 through 3.1, and Windows 95-ME are really separate OSes. Windows 3.1 booted into DOS first but that was just to load drivers. Windows entirely replaced the DOS functions that were there when it loaded. They probably yanked some Windows 3.1 code for '95, but it was really a totally new OS, including lots of modern features.
posted by delmoi at 1:55 AM on October 24, 2009

Vista was a complete reboot build initially, but it was going so badly that they scrapped development in 2005 and started over as an evolution from the server 2003 baseline (which was also the baseline for XP 64). The vista kernel was then the baseline for server 2008.

Now windows 7 is out, and it shares a lot of similiarities with server 2008R2.

Windows 7 is just an upgrade to vista in that sense rather than a near complete rebuild as the NT line and 95 line were. Mostly they've fine tuned it, adjusted performance to give priority to user interface interactions.

That said, I've been running windows 7 on various machines in it's various incarnations since the first beta builds. Going back to vista computers is like wading in treacle.
posted by ArkhanJG at 2:55 AM on October 24, 2009 [2 favorites]

Windows 7 is definitely not built from the ground up. It's a very refined version of Vista.

However, let's be clear that while Vista is "built on NT", it still represented an insanely comprehensive rewrite of large components and features of the operating system. Things like abstracting the display layer, Windows Presentation Foundation (though WPF is available in XP SP3), an entirely rewritten network and audio driver stack, and a good deal of other sweeping changes to the code represent more than just a bolted on feature set over XP.

XP itself is probably more similar (in terms of shared code) to 2000 than Vista is to XP.

Windows 7 is probably closer to Vista than Vista is to XP, or XP is to 2000.

However, Windows 7 fixed many, many of the things that were "wrong" with Vista. In my mind, Vista didn't get a particularly fair shake. Because of the rewriting of the driver stacks, manufacturers really needed to, in some cases, completely rewrite their drivers to work with it. This took longer than anyone would've liked. The result was an operating system that, at launch, appeared to not play nice with hardware at all.

Windows 7 can, in almost every case, use the Vista drivers, because not enough has changed to the structure of the OS and how it manages those resources to warrant a significant change again. Vista paved the way for how things needed to be handled going forward (which is why upgrading your display drivers no longer requires a reboot, for instance) but it was painful. The other common complaint is UAC, which has been made more granular in W7, but which only annoyed me as much as I'd let it.

My personal biggest complaint about Vista was the fact that file transfers, decompressing zipped files (using the Explorer extracter) and network transfers were EXCRUCIATINGLY slow in many cases. I don't really understand what caused this dramatic of a failure, but Windows 7 has addressed that entirely, on all fronts. They've also reduced from-scratch install times to about 25 minutes-til-desktop, and bootup and shut down times as well. Oh, and they've gotten Sleep mode working the way it should.

Basically, Microsoft set themselves up for failure with Vista because they wanted to do a lot of spring cleaning and foundation building, to empower machines to work properly going forward. They didn't offer enough compelling features and interface components, or things that the end user would care about, to overshadow the issues people were having with incompatible hardware and software, though. So everyone just flat out thought the OS sucked. Aside from the file transfer and zip issues, all of my hardware worked just fine, and I thought Vista was a perfectly fine OS. (I turned off the UAC stuff.)

And yet I bought Windows 7. I've been running it since January, and I love it. It represents probably the biggest step forward in usability to hit Windows since Windows 95 brought about the taskbar and start menu. The new docked "superbar" taskbar is brilliant. It took some getting used to, but now I love it. The Aero Peek functionality (hover over a thumbnail and the window comes to the forefront with everything else fading out so that you can see what's there) is remarkably useful. And the gesture-based controls are great, even on a mouse/keyboard setup. (You can drag a window to the top of the screen and it will maximize it on mouse release. You can pull the entire bar down and it'll "snap" out of maximize mode as well. This sounds minor but is insanely useful after you play with it a bit.)

A handful of other great changes really put everything where you need it and make things work for you. The operating system is stable (much like Vista was, really, about a year in and after everyone got their drivers right) and very polished. Let's be clear: when your programs crash, it's probably because the software was written poorly, or because of bad drivers. The operating system itself rarely-if-ever seizes up and, frankly, hasn't much since the XP/2000 revolution. It does what I need it to do and it works really well. Windows 7 is a great evolution of Vista and fixes basically every flaw that caused it to frustrate people so much.
posted by disillusioned at 3:09 AM on October 24, 2009 [5 favorites]

Windows 7 is more similar to Vista than Snow Leopard is to Leopard. While Microsoft's baby has more immediately user-visible differences from its predecessor, the guts are pretty much the same old thing. OSX 10.6 may seem similar to 10.5 in visible features apart from the moderate speed boost, but the underlying machinery has been changed in many substantial ways that represent a modernization of a large portion of the Apple platform. In simplistic terms: Win7 is meant to address the errors of the recent past; Snow Leopard is meant to lay a foundation for the future.
posted by majick at 4:34 AM on October 24, 2009

This is mostly a meaningless question. A 2010 Honda Civic is an "upgraded" version of a 1985 Honda Civic. Linux-based operating systems have been upgrading for decades, etc.

If you want to be specific, Windows 7 is version 6.1.7100 of the NT kernel. Windows Vista is version 6.0, and XP was 5.1. But this is largely meaningless.
posted by blue_beetle at 6:34 AM on October 24, 2009 [1 favorite]

majick: "OSX 10.6 may seem similar to 10.5 in visible features apart from the moderate speed boost, but the underlying machinery has been changed in many substantial ways that represent a modernization of a large portion of the Apple platform."

Umm wut? They rebuilt some binaries for 64bit and added yet another multithreading library. Perhaps you can offer me some citations I can to add to wikipedia?
posted by pwnguin at 10:29 AM on October 24, 2009

pwnguin - I think they also re-wrote a lot in cocoa (like Finder), stripped out PPC and tried to tighten up the code. On the other hand, at least based on initial reports, Snow Leopard seems to have a lot of teething problems compared to Win 7 - many people experience substantially worse performance compared to Leopard, which is an outrage considering that Apple only has to address very limited range of hardware, and in fact controls the entire hardware/software stack, unlike Windows which has to deal with basically infinite number of configurations of hardware. And can you imagine the publicity and hullabaloo if Win 7 lost all your data upon upgrading from Vista, the way Snow Leopard managed to do for many people - a bug of epic proportions.
posted by VikingSword at 11:30 AM on October 24, 2009

Dos, Windows 1 through 3.1, and Windows 95-ME are really separate OSes. Windows 3.1 booted into DOS first but that was just to load drivers. Windows entirely replaced the DOS functions that were there when it loaded. They probably yanked some Windows 3.1 code for '95, but it was really a totally new OS, including lots of modern features.

Well, 16-bit windows apps used DPMI (DOS Protected Mode Interface) to do a bunch of things. Heck, some TSRs were compatible with Windows 3.1 and you could tell Windows to do things with them in your SYSTEM.INI. And Win95 still did include DOS 7 (you could get to it using the boot menu and everything). So there wasn't that clear a break. But DOS provided so little OS functionality that it is true that most everything interesting (drivers, task scheduling, memory management) had to be written (not re-written!) from the ground up.
posted by aubilenon at 12:25 PM on October 24, 2009

"Perhaps you can offer me some citations I can to add to wikipedia?"

I'm not your bibliography desk and am slightly hostile toward expending effort pushing a boulder up a Wikipedia hill, but there's a bit more than a recompile involved in the Snow Leopard release. Moving to LLVM, the ObjC Runtime 2 stuff, the addition of a 64 bit kernel and drivers, complete reimplementation of NeXT Browser / Finder under Cocoa 64, deprecation of a ton of Carbon transition cruft from the Toolbox / 68K / PPC days, stripping out some of the unfinished bits that were languishing in release (like the dead-ended ZFS implementation) introduction of the new Quicktime frameworks (arguably a mixed bag of improvements, considering the holes in the first shot at it), introduction of compressed app bundles, the dropping of PPC binaries, the GPGPU stuff and integrating it to the "new multithreading library" you mention, plus the usual generational improvements to existing frameworks.

Compared to the Windows 7 changes which largely amount to "we changed the shell a bit, added some awful looking visual bling and clunky visual effects, spent more time on the WHQL cycle, and polished the hell out of the negative publicity pain points" Snow Leopard's a pretty substantial upgrade.

Product-cycle wise, Snow Leopard is in some respects equivalent to the Vista release: A big housecleaning release that ought to result in improved products down the line. The difference? Apple didn't botch their OS release, wasted nearly no effort trying to build "hard" end to end DRM infrastructure for media, and avoided the driver model transition nightmare that Vista had by virtue of (for the most part) controlling the hardware.

Frankly, LLVM and Runtime 2.0 are in and of themselves justification for calling it a major platform improvement. You may not know the details about them, and that's fine as you don't have to, but the whole frickin point of the 10.6 release was to get these significant changes into the ecology with as little pain as possible. That goal clearly seems to have been met.
posted by majick at 2:58 PM on October 24, 2009 [1 favorite]

For comparison, Apple rewrote their OS back in 2001 with OSX Cheetah

Well, OS X is really a direct descendant of NeXTSTEP, first released in 1989, which itself runs on the Mach kernel (which first surfaced in 1985) and inherits a bunch from BSD (1977), so let's just say it's difficult to compare these things meaningfully with a soundbite.
posted by chrismear at 9:34 AM on October 26, 2009