Windows 8 Developer Preview was released last fall. And not
coincidentally, this was the fourth time in a row I spoke exclusively
about Windows 8: People are fascinated by--and scared by--Microsoft's
next operating system in ways they haven't been since Longhorn or,
perhaps, Windows 95. It's something that I even I need to keep in the
back of my mind since of course I have my own doubts, most of which are
directly related to Microsoft's refusal to speak clearly about its
plans.
That said, the groups I speak to are largely made up of
very technical people with a business focus, so they have specific
concerns about Windows 8, as well as specific kinds of concerns. Still,
many of their questions are generally interesting even to non-technical
people. So I figured I could address some of these questions in a series
of articles about Windows 8 that will serve as background for the
material I'm preparing for the book Windows 8 Secrets.
First
up is the new Windows Runtime, or WinRT, since this forms the core of
the new operating system and is, perhaps, the centrally most confusing
concept in Windows 8 thanks to its position, or relationship, with the
Start screen and Metro-style apps, and, of course, the classic Windows
desktop and those applications as well.
Note:
This is a guide for end users, not developers or Windows internals
experts. The goal here is to be accurate conceptually, and it's likely
that there are some technical omissions or shortcuts in this article,
given the nature of the topic. While I'm not hugely concerned about that
sort of thing, I am interested in any errors you do find. So do let me
know.
It's also worth noting that this is one area where
Microsoft has been very forthcoming. We criticize them for silence, but
with WinRT, the company has been transparent, though of course the topic
is complex and confusing.
OK, let's dive in.
As a modern
operating system, Windows has, of course, always had a runtime engine,
an environment in which native applications run. One of these native
applications is very special, since it provides the interface with which
users interact with that runtime and environment; that application is
called the shell. In the Windows 3.x days, Program Manager was the
Windows shell. But that changed in Windows 95 to Windows Explorer, a
situation that continued through the most recent Windows version,
Windows 7.
In Windows 8, the Explorer shell is being replaced by
the Start screen. But this isn't just a surface change, and the Start
screen isn't "a thing on a thing." Instead, the Start screen, as the new
Windows shell, is the visual representation of a new runtime engine
which in this case is simply called the Windows Runtime, or WinRT for
short.
And the Explorer desktop, interestingly, is essentially an
app, or at least a separate environment, that runs alongside the new
shell. One might conceptually (though not technically) compare this to
the situation with MS-DOS and Explorer in Windows 9x: Both existed, both
ran next to each other for all intents and purposes. And both had
various tendrils into the other such that, for example, Explorer and the
Windows 9x runtime actually relied on DOS in some ways. These things
are never as clean as depicted in Microsoft's diagrams.
Architecturally,
WinRT fits into Windows at a very deep level, which makes sense. Thanks
to componentization work that began in the buildup to Windows Vista in
the mid 2000s, Windows is now highly componentized, a modular system in
which different components, or parts, can be mixed and matched, like a
puzzle with multiple solutions, to form different Windows 8 versions,
including the phone, the desktop versions, Server, and so on.
At
the base of this architectural view of Windows is Windows Core, or what
used to be called MinWin. This includes the Windows kernel, user mode,
services, and other low-level bits. WinRT, interestingly, does not
completely sit on top of Windows Core. Instead, much of WinRT is part of
Windows Core. This, of course, explains Microsoft's contention that the
new Windows runtime is not "a thing on a thing". It's the Windows
runtime engine, pure and simple.
As with Windows itself, the
Window Runtime is itself also made up of layers that provide levels of
functionality to the shell and to Metro-style apps. At the bottom,
conceptually, are low-level services such as memory management,
cryptography, and globalization; these are considered part of the
Windows Runtime Core. Above them are layers related to devices
(including sensors), media, and communications and data (contacts, local
and cloud storage, web, notifications, and much more). And above that
is the UI layer, with the various WinRT-supported app development
models: HTML5/CSS, XAML, DirectX, and the like.
(Developers use
APIs for each of these layers, contained in the Windows 8 SDK, to create
Metro-style apps. These APIs are, for now, horribly (un)documented, so
its unclear what quantity of high-quality apps we can expect without a
lot of handholding from Microsoft. That situation, of course, will
improve over time.)
Microsoft explained this even more simply at
the BUILD conference last September, as it turns out. Microsoft WinRT
development manager Martin Lovell said during his session "Lap Around
the Windows Runtime" that "WinRT is the Windows platform."
Accepting
Microsoft's contention that WinRT is indeed the new Windows runtime
engine, we arrive at an obvious question: Why? Why would Microsoft
replace something that has worked so well and so efficiently with
something that is so new, so different, and--for now, at least--this
untested and, to developers, unknown?
I think the simplest way to
explain this is that Microsoft had hit a brick wall with its existing
technologies. To understand this, I'm going to need to take a short
detour into how Windows software has been developed over the past 15
years.
Win32, the API/developer basis for its Explorer-based
platform, isn't just long in the tooth--it was created for Windows NT in
the early- to mid-1990s--it's been usurped by more modern APIs several
times, starting with the C++-based MFC (Microsoft Foundation Classes),
but more recently by managed code, .NET-based environments including the
.NET Framework, Windows Presentation Foundation and Silverlight.
For
all the advantages of .NET, the central problem is that it does not
produce "native" code. That is, .NET environments, by nature, are
abstractions of the native environment that are, yes, more elegant, but
also further removed from the core of Windows. So they suffer from
performance issues above all, but also from the fact that they offer
only a subset of the full spectrum of possible platform capabilities. So
developers often turn to C or even assembly language when they need
better performance, or to access functionality that is simply not
exposed by whatever .NET environment they chose.
But what if .NET-style development were to become "native" Windows development? Doesn't this sound like the best of both worlds?
Hard
core developers may bristle at the notion that WinRT development is
"native" development, but it's a fair enough assertion. Using the new
WinRT-based APIs available in Windows 8, developers can use the modern,
managed code languages they love from .NET--like C# and Visual
Basic--along with the XAML user experience markup language and the
familiar, clean, and modern managed code-style APIs. WinRT is also more
egalitarian than .NET since it also offers even more choice: Now you can
also use web technologies--HTML 5, CSS, and JavaScript--which are
simpler and more approachable, or those with serious performance needs
can use DirectX. In each case, however, the developer benefits from over
a decade of improvements to these types of programming interfaces.
Win32, suddenly, isn't just out of date. It's passé.
There's a
bit more to this evolution, some of which involves the notion of
asynchronous programming and so on, but let's not get too far afield.
The point is that Microsoft is modernizing everything here: The runtime
engine and shell for users, but also the development tools, languages,
APIs, frameworks, environment, and more. Everything is being overhauled
to be better, simpler, and more modern.
That's the theory, anyway.
From
the user's perspective, these changes will have important
ramifications, not just in the way you interact with Windows on a
day-to-day basis but also in such areas as how Windows and the apps that
run in it are updated over time. This isn't a surface coat of paint,
it's a complete reset, though of course the addition of the "legacy"
Windows desktop provides the important backwards compatibility that
customers expect and Microsoft always delivers. Microsoft calls this a
"no compromises" approach. Again: The best of both worlds.
As
with any evolution, there will be growing pangs. This is what happened
when we moved from DOS/Windows 3.x to Windows 95 to NT as well. During
that transition, DOS migrated from being the core OS to being an
integrated runtime engine and then, finally, to being a simple command
line interpreter that ran on top of the "real" OS.
In Windows 8,
WinRT and the Start screen will run alongside Win32 and the Explorer
desktop. Both environments will be available to the user, and each will
have its strengths and weaknesses in different scenarios. Win32 will,
for now, include functionality that is simply not available in WinRT,
though hopefully that will change over time. But WinRT, of course, is
where the action is: Though some small updates to the Win32 APIs have
indeed been introduced in Windows 8, Win32 is largely deprecated and
heading towards maintenance mode. All of the big changes and
improvements are, and will be, occurring in WinRT.
Over time, I
expect Explorer to be further deprecated and eventually removed. Knowing
Microsoft, this will happen slowly because of compatibility concerns.
But WinRT and its Metro-style user experience is the future, regardless,
and WinRT is the runtime engine that will drive a new generation of
Windows versions. It's as exciting as it is scary.
Thanks & Regards,
"Remember Me When You Raise Your Hand For Dua"
Raheel Ahmed Khan
System Engineer
send2raheel@yahoo.com
send2raheel@engineer.com
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