Click here to close now.


Microsoft Cloud Authors: Jordan Sanders, Carmen Gonzalez, Pat Romanski, Keith Mayer, Jayaram Krishnaswamy

Related Topics: Microsoft Cloud

Microsoft Cloud: Article

WinFS: The Windows Storage Platform of the Future

How to Write Applications that Take Advantage of WinFS

The next version of the Windows operating system (codenamed "Longhorn") has a new storage subsystem (codenamed "WinFS"). In this article, we will try to understand the need for "WinFS"; define "WinFS", its type system, and its data model; and learn how to write applications that take advantage of "WinFS".

Why Does Windows Need a New Storage Subsystem?
The hardware industry is confidently striding towards conquering the 3T challenge (a teraflops processor, a terabyte hard disk, and a terabits per sec bandwidth). Increase in the size of hard disk storage has been complemented by the exponential increase in the production of digital data. The amount of digital data being born daily is so phenomenal that the pen, the paper, and the typewriter have achieved the status of endangered stationery. Digital data is stored by operating systems on magnetic media - like hard disks. Windows uses file systems like NTFS and FAT32 to organize data on hard disks that are divided into logical drives. Each drive has a root folder, which can have one or more files and folders. Data is stored in files.

Data has personality. It can be documents (text, DOC, PDF, RTF, PostScript formats), images (bitmap, GIF, JPEG, PNG, WMF formats), audio (WAV, MP3, WMA, AIFF, formats), video (MOV, MPEG, AVI, ASF, QuickTime formats), and more. Along with data, these formats also store rich metadata. NTFS and FAT32 are capable of reading only basic metadata from files, like their name, size, date modified, and type (derived from the file extension). So, if I want to search all songs of a particular artist, I can't do it just by using the file system. I'll need a specialized application like Windows Media Player, which is capable of reading the rich metadata provided by all audio files.

What is "WinFS"?
"WinFS" is the Windows storage platform of the future. It solves many of the problems associated with current file systems by storing data and its metadata together. This way data can be organized, searched, shared, and related depending upon what it is and not what it's called (filename)! "WinFS" also makes it easy to deal with non-file-backed data like personal contacts, e-mail messages, and event calendar.

"WinFS" allows a user to organize data with great flexibility. Using "WinFS", a user can group data according to common characteristics, create a customized containment hierarchy to hold data, and associate one piece of data to another via relationships. This organizational flexibility provides the user with greater flexibility when searching for data. The user can search for data based on its attributes, its relationship with other data, and by its storage location.

Searching Data
Because of its ability to organize data based on various parameters, "WinFS" presents data as a directed acyclic graph (DAG) instead of as a tree (as in NTFS and FAT32). In NTFS and FAT32, since data is stored as a tree, it can be located based only on a single criteria (its directory path), while in "WinFS", since data is stored as a graph it can be searched based on multiple criteria.

Sharing Data
"WinFS" facilitates data sharing among various applications by giving file-backed data (documents, audio video, media, and so on) as well as non file-backed (e-mail, contacts, appointments, and so on), permanent residency status in the operating system and providing a unique API to access them. Now different applications can use these common pieces of data without worrying about maintaining individual data stores and the associated synchronization.

WinFS Building Blocks
Figure 1 illustrates the various building blocks of "WinFS".

Core "WinFS"
"WinFS" does not supplant NTFS; rather, it utilizes the basic file system services of NTFS. The core building block of "WinFS" includes the relational storage engine that provides file system services like ACL support, import/export, and quota management.

Data Model
"WinFS" defines a rich data model that resides on top of a relational storage engine. "WinFS" represents a piece of data (item) as a tuple in a relation. The attributes of the tuple describe the piece of data. Items can be related to each other by defining relationships between the tuples. "WinFS" also provides the ability to extend items and relationships.

"WinFS" has built-in schemas to understand the rich metadata associated with your data. Some of the built-in schemas are for common data like documents, e-mail, contacts, appointments, tasks, and more. "WinFS" also allows you to write custom schemas for your own data.

"WinFS" provides certain services like synchronization and rules. These services are layered on top of core "WinFS" and provide "WinFS" with extended functionality. For example, the synchronization service enables you to synchronize two or more "WinFS" stores.

"WinFS"provides support for multiple programming models: object-oriented, relational, and XML based. "WinFS" can also be programmed using the Win32 API.

"WinFS" Type System Basics
"WinFS" is a "strongly typed" storage system. All data stored in "WinFS" is typed; that is, it is an object of some "WinFS" type. To understand the "WinFS" type system, we first have to understand the following four concepts:

  • Items: All data is stored in WinFS  as a type specialized from Item (System.Storage.Item). Examples of types that derive from the Item are: Contact, Document, Task, and Event (all of which are found in the System.Storage.Core namespace)
  • ScalarTypes: An atomic piece of information that describes an item.
  • NestedTypes: A set of information that can be stored about an item. A nested type can have other nested types and scalar types in it.
  • Relationships: Relate one item (source) to another (target). Relationships can be of three types:
    - Holding relationship: The source controls the lifetime of the target. These relationships are many-to-many, that is, a source can "hold" multiple targets and a target can be "held" by multiple sources. If a target looses all sources, it's deleted.
    - Reference relationship: Similar to a holding relationship but without the lifetime management of the target.
    - Embedding relationship: The source embeds the target. Strictly one-to-one.

Programming "WinFS"

In this section, we'll take a brief look at the object-oriented managed API provided by "WinFS". This API allows us to search, relate, and act upon data stored by WinFS

.An installation of Longhorn will have a single instance of "WinFS" service running on it. A "WinFS" instance can maintain multiple data stores. Each data source is referenced by its UNC path syntax as shown below:


All "WinFS" instances have a default store (DefaultStore). The default store on your "Longhorn" system will be called:


To program "WinFS", you have to get hold of an ItemContext object. This is done by calling the static Open method of the ItemContext class. The method is passed the UNC path of the store you want to program. If you pass nothing, the ItemContext refers to the default store.

All the types that are required to program "WinFS" can be found in three assemblies: System.Storage. dll, System.Storage.Schema.dll, and WinCorLib.dll.

As an example, Listing 1 is code that prints out all folders in the default store.

A very useful class provided by "WinFS" is the ItemSearcher (System.Storage.ItemSearcher) class, which allows you to search for items in a particular item type. Each item type (for example, Contact, Document, Folder, Event, and so on) has a static method called GetSearcher that takes in the ItemContext object and returns the ItemSearcher. Using the ItemSearcher, you can search for the items you need.

For example, Listing 2 uses the ItemSearcher to search for all documents whose title begins with the string 'Result'.

In this brief survey of "WinFS", we have seen that the future of data is with context-based storage systems. "WinFS" will provide the basis on which advanced data-mining tools are going to be built for the personal computer.

More Stories By Mujtaba Syed

Mujtaba Syed works as a software architect with Marlabs Inc. He is an MCSD
(early achiever) and loves to speak about and write on Microsoft .NET. Mujtaba has been programming the Microsoft .NET Framework since its beta 1 release. His current interests are focused on Longhorn.

Comments (2) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

Most Recent Comments
Mujtaba Syed 06/08/04 03:11:22 PM EDT

It''s corrected now.

Mujtaba Syed 06/08/04 02:29:18 PM EDT

Somehow the online version is showing WinFX at all places it should show WinFS! We will get this rectified ASAP. Thanks.

@ThingsExpo Stories
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data shows "less than 10 percent of IoT developers are making enough to support a reasonably sized team....
Just over a week ago I received a long and loud sustained applause for a presentation I delivered at this year’s Cloud Expo in Santa Clara. I was extremely pleased with the turnout and had some very good conversations with many of the attendees. Over the next few days I had many more meaningful conversations and was not only happy with the results but also learned a few new things. Here is everything I learned in those three days distilled into three short points.
DevOps is about increasing efficiency, but nothing is more inefficient than building the same application twice. However, this is a routine occurrence with enterprise applications that need both a rich desktop web interface and strong mobile support. With recent technological advances from Isomorphic Software and others, rich desktop and tuned mobile experiences can now be created with a single codebase – without compromising functionality, performance or usability. In his session at DevOps Summit, Charles Kendrick, CTO and Chief Architect at Isomorphic Software, demonstrated examples of com...
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningful and actionable insights. In his session at @ThingsExpo, Paul Turner, Chief Marketing Officer at...
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
In his General Session at 17th Cloud Expo, Bruce Swann, Senior Product Marketing Manager for Adobe Campaign, explored the key ingredients of cross-channel marketing in a digital world. Learn how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects).
The Internet of Everything is re-shaping technology trends–moving away from “request/response” architecture to an “always-on” Streaming Web where data is in constant motion and secure, reliable communication is an absolute necessity. As more and more THINGS go online, the challenges that developers will need to address will only increase exponentially. In his session at @ThingsExpo, Todd Greene, Founder & CEO of PubNub, exploreed the current state of IoT connectivity and review key trends and technology requirements that will drive the Internet of Things from hype to reality.
Two weeks ago (November 3-5), I attended the Cloud Expo Silicon Valley as a speaker, where I presented on the security and privacy due diligence requirements for cloud solutions. Cloud security is a topical issue for every CIO, CISO, and technology buyer. Decision-makers are always looking for insights on how to mitigate the security risks of implementing and using cloud solutions. Based on the presentation topics covered at the conference, as well as the general discussions heard between sessions, I wanted to share some of my observations on emerging trends. As cyber security serves as a fou...
We all know that data growth is exploding and storage budgets are shrinking. Instead of showing you charts on about how much data there is, in his General Session at 17th Cloud Expo, Scott Cleland, Senior Director of Product Marketing at HGST, showed how to capture all of your data in one place. After you have your data under control, you can then analyze it in one place, saving time and resources.
With all the incredible momentum behind the Internet of Things (IoT) industry, it is easy to forget that not a single CEO wakes up and wonders if “my IoT is broken.” What they wonder is if they are making the right decisions to do all they can to increase revenue, decrease costs, and improve customer experience – effectively the same challenges they have always had in growing their business. The exciting thing about the IoT industry is now these decisions can be better, faster, and smarter. Now all corporate assets – people, objects, and spaces – can share information about themselves and thei...
The cloud. Like a comic book superhero, there seems to be no problem it can’t fix or cost it can’t slash. Yet making the transition is not always easy and production environments are still largely on premise. Taking some practical and sensible steps to reduce risk can also help provide a basis for a successful cloud transition. A plethora of surveys from the likes of IDG and Gartner show that more than 70 percent of enterprises have deployed at least one or more cloud application or workload. Yet a closer inspection at the data reveals less than half of these cloud projects involve production...
Continuous processes around the development and deployment of applications are both impacted by -- and a benefit to -- the Internet of Things trend. To help better understand the relationship between DevOps and a plethora of new end-devices and data please welcome Gary Gruver, consultant, author and a former IT executive who has led many large-scale IT transformation projects, and John Jeremiah, Technology Evangelist at Hewlett Packard Enterprise (HPE), on Twitter at @j_jeremiah. The discussion is moderated by me, Dana Gardner, Principal Analyst at Interarbor Solutions.
Discussions of cloud computing have evolved in recent years from a focus on specific types of cloud, to a world of hybrid cloud, and to a world dominated by the APIs that make today's multi-cloud environments and hybrid clouds possible. In this Power Panel at 17th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists addressed the importance of customers being able to use the specific technologies they need, through environments and ecosystems that expose their APIs to make true change and transformation possible.
Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
Microservices are a very exciting architectural approach that many organizations are looking to as a way to accelerate innovation. Microservices promise to allow teams to move away from monolithic "ball of mud" systems, but the reality is that, in the vast majority of organizations, different projects and technologies will continue to be developed at different speeds. How to handle the dependencies between these disparate systems with different iteration cycles? Consider the "canoncial problem" in this scenario: microservice A (releases daily) depends on a couple of additions to backend B (re...
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound effect on the world, and what should we expect to see over the next couple of years.
Container technology is shaping the future of DevOps and it’s also changing the way organizations think about application development. With the rise of mobile applications in the enterprise, businesses are abandoning year-long development cycles and embracing technologies that enable rapid development and continuous deployment of apps. In his session at DevOps Summit, Kurt Collins, Developer Evangelist at, examined how Docker has evolved into a highly effective tool for application delivery by allowing increasingly popular Mobile Backend-as-a-Service (mBaaS) platforms to quickly crea...
Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Day 2 Keynote at 17th Cloud Expo, Sandy Carter, IBM General Manager Cloud Ecosystem and Developers, and a Social Business Evangelist, wil...
PubNub has announced the release of BLOCKS, a set of customizable microservices that give developers a simple way to add code and deploy features for realtime apps.PubNub BLOCKS executes business logic directly on the data streaming through PubNub’s network without splitting it off to an intermediary server controlled by the customer. This revolutionary approach streamlines app development, reduces endpoint-to-endpoint latency, and allows apps to better leverage the enormous scalability of PubNub’s Data Stream Network.
Apps and devices shouldn't stop working when there's limited or no network connectivity. Learn how to bring data stored in a cloud database to the edge of the network (and back again) whenever an Internet connection is available. In his session at 17th Cloud Expo, Ben Perlmutter, a Sales Engineer with IBM Cloudant, demonstrated techniques for replicating cloud databases with devices in order to build offline-first mobile or Internet of Things (IoT) apps that can provide a better, faster user experience, both offline and online. The focus of this talk was on IBM Cloudant, Apache CouchDB, and ...