Windows 8 includes mitigation enhancements that further reduce the likelihood of common attacks. Some of these improvements include:

Address Space Layout Randomization (ASLR). ASLR was first introduced in Windows Vista and works by randomly shuffling the location of most code and data in memory to block assumptions that the code and data are at same address on all PCs. In Windows 8, we extended ASLR’s protection to more parts of Windows and introduced enhancements such as increased randomization that will break many known techniques for circumventing ASLR.

Windows kernel. In Windows 8, we bring many of the mitigations to the Windows kernel that previously only applied to user-mode applications. These will help improve protection against some of the most common type of threats. For example, we now prevent user-mode processes from allocating the low 64K of process memory, which prevents a whole class of kernel-mode NULL dereference vulnerabilities from being exploited. We also added integrity checks to the kernel pool memory allocator to mitigate kernel pool corruption attacks.

Windows heap. Applications get dynamically allocated memory from the Windows user-mode heap. Major redesign of the Windows 8 heap adds significant protection in the form of new integrity checks to help defend against many exploit techniques. In addition, the Windows heap now randomizes the order of allocations so that exploits cannot depend on the predictable placement of objects—the same principle that makes ASLR successful. We also added guard pages to certain types of heap allocations, which helps prevent exploits that rely on overrunning the heap.

Internet Explorer. “Use-after-free” vulnerabilities represented nearly 75% of the vulnerabilities reported in Internet Explorer over the last two years. For Windows 8, we implemented guards in Internet Explorer to prevent an attacker from crafting an invalid virtual function table, making these attacks more difficult. Internet Explorer will also take full advantage of the ASLR improvements provided by Windows 8.

Windows 8 Developer Preview only came out a few days ago, so many of the virtualization products on the market have not yet been updated to work well with it. We are working closely with all of the major manufacturers of virtualization products to support Windows 8 as we move toward release.

Forum members are reporting success using a few products. Of the most popular options, our baseline assessment is as follows:

Functional:
•Hyper-V in Windows 8 Developer Preview
•Hyper-V in Windows Server 2008 R2
•VMware Workstation 8.0 for Windows
•VirtualBox 4.1.2 for Windows

Non-functional:
•Microsoft Virtual PC (all versions)
•Microsoft Virtual Server (all versions)
•Windows 7 XP Mode
•VMWare Workstation 7.x or older

The software maker is currently readying a new file system as an offshoot to the original concept of Windows Future Storage (WinFS). According to sources familiar with the company’s plans, the new file system is called Resilient File System. The project originally started out as Monolithic NTFS (MNTFS) and then ended up codenamed Protogon before the final Resilient File System (ReFS) naming was chosen. Screenshots from the latest Windows 8 builds surfaced on Thursday demonstrating the new file system in action.

The naming reveals some of the concepts around what Microsoft is trying to achieve with the new file system. The idea is that server variants of Windows 8 will be able to utilise the new technology to improve file system resilience to hardware and software errors. The technology will not be widely used and is designed for specific use by server administrators. As a result, client versions of Windows 8 will not be able to utilise the new file system according to our sources.

Microsoft’s original Windows Future Storage (WinFS) concept made its way into Longhorn (Windows Vista) builds during the early beta phases. WinFS was first demonstrated in 2003 at the company’s Professional Developers Conference. Microsoft promised an advanced storage subsystem designed to manage data by means of a database. The WinFS database would allow any type of information to be stored in it alongside a defined schema for the data type. The idea was to speed up searching and data sharing between applications. Microsoft ditched the idea before Windows Vista was brought to market.

Storage Spaces in Windows 8 will link up with Microsoft’s new Resilient File System (ReFS) to create a new level of redundancy in Windows 8. Microsoft’s new Storage Spaces feature of Windows 8 will automatically correct any data that has become corrupted over the various Pool Drives in a particular data set. The feature is similar to software RAID but can utilise Microsoft’s ReFS for increased redundancy.

Storage Spaces screenshots were posted by PCBeta on Monday and demonstrate the setup process for the feature. According to our own sources, Storage Spaces will only be present in Server versions of Windows 8, with the possibility of the feature making its way to high-end client SKUs. Microsoft will support petabyte data set sizes with Storage Spaces and ReFS.

Windows Store will be the only place to get metro apps

In the beta, we’ve added a new option to the detailed conflict resolution dialog. By checking the box in the bottom left of the dialog, you can filter out all files that match on name, size (down to the byte) and time (down to the granularity of the file system timestamp: 2 seconds for FAT, 100 nanoseconds for NTFS). The system will skip copying or moving these files. This functionality adds no additional time to the operation, works both locally and across networks, and on all types of systems and storage.

JL asked:

You know when you start a big copy job and realize that you are doing it over the wireless so you grab a network cable and plug it in? Does the file copy know to utilize the faster connection now?

If both sides of the copy operation are on Windows 8 machines, yes, it will be able to take advantage of the increased network throughput on the fly, thanks to advancements in the Server Message Block (SMB) protocol to support multiple channels.

Tobi asked:

Will it be possible to pause the copy operation and resume it after reboot/sleep/hibernate?

In the beta, when a system sleeps or hibernates, the copy operation will automatically pause, and when the machine wakes, you can choose to resume the copy by clicking the depressed pause button. (We decided not to have copies automatically resume on wake, as the system environment may have changed significantly in the interim and we do not want to cause an error.)

gawicks asked:

Please please display all the copy 'error dialogs' after the copying has completed so I don't have to sit in front of the machine all the time.

We have two types of user interaction that can occur during a copy job - we break these into two groups, “confirmations” and ”interrupts.” Confirmations like “Are you sure you want to permanently delete this file?” need to be completed before the copy operation can start. Interrupts are issues that the system encounters while copying, things like “File not found,” “File in use,” and file name conflicts.

The system presents all confirmations before it starts to move or copy files. While copying, any interrupt issues are queued and presented once the system has completed all the work it can. In the beta, we’ve made improvements in how confirmations are presented, making sure they don’t get lost amongst existing running copies.

When Microsoft killed Windows Home Server's "Drive Extender" technology, we mourned its loss but held up hope that the company would persevere with the concept. The company has done just that with a new Windows 8 feature called Storage Spaces, described in a lengthy post to its Building Windows 8 blog.

With Storage Spaces, physical disks are grouped together into pools, and pools are then carved up into spaces, which are formatted with a regular filesystem and are used day-to-day just like regular disks.

Unlike RAID systems of old, but in common with other modern storage technologies such as Solaris' ZFS and Linux's btrfs, pools can use disks of different interface technologies—USB, SATA, Serial Attached SCSI—and different, mismatched sizes. New disks can be added to a pool at any time. Pools can also include one or more hot spares: drives allocated to a pool but kept in standby until another disk in the pool fails, at which point they spring into life.

Storage in a pool is then distributed among one or more spaces. Each space can have its own redundancy policy, with three kinds of fault tolerance offered: 2-way mirroring, 3-way mirroring, and RAID 5-like parity. With the mirrored options, a space's data is stored either twice or three times within a pool. With the parity option, the system will compute additional information and store this within the pool. If any disk in the pool fails, the data can be reconstructed using this additional information.

Spaces can be thinly provisioned, allowing the creation of spaces that are larger than the underlying pool. This allows potentially simpler management—a large "media" space for TV shows and movies could be created with some large size, say 50 TB, with only 2 TB of physical capacity in the pool. As more shows are recorded or downloaded, and space becomes tighter, additional drives can be added to the pool; the space will then use this extra capacity with no further configuration required.

The new technology appears to be superior to Windows Home Server's Drive Extender technology in just about every regard, and its integration into the core operating system indicates that it's robust enough for mainstream usage. The blog post implies that Storage Spaces are ready even for enterprise workloads, making mention of the ability to scale up to "very large-scale enterprise datacenter[s]", with pools made up of "hundreds of disks"—not a promise anyone would make of the home user-oriented Drive Extender.

Perhaps the only fly in the ointment for most home users is that in Windows 8, Storage Spaces will not be bootable. The company says that guidance will be offered on how to partition disks so that a partitioned boot disk can be added to a pool, but that straightforward booting unfortunately won't be possible. On some levels, this is unsurprising: many advanced filesystem and storage systems are not bootable in their initial version, and Storage Spaces certainly won't be the first. On the other, it would certainly be a desirable addition, as it would ensure that even if a boot disk failed, your PC would remain operational.

The first mention of Storage Spaces were made at Microsoft's BUILD conference in September 2011. At BUILD, the company did not offer significant details about the technology, and spoke of it in relation to Windows Server 8. Judging by the nature of the usage scenarios outlined in the blog post—storing videos and photographs, using USB external disks—it appears that Storage Spaces will be a feature of the desktop operating system too. We've asked Microsoft for clarification on this point.

Update: As expected, Storage Spaces will indeed be a feature of both desktop and server editions of the operating system.

When the feature does indeed ship in desktop Windows, it will overnight obsolete a range of SOHO-oriented storage systems; products like Drobo and ReadyNAS will find it hard to survive in a Windows 8 world.

Storage Spaces will give Windows 8 flexible, fault-tolerant pooling of disk space, and will make storage management simpler and much more powerful. But there's more to robust file storage than replicating data between disks: preventing and detecting corruption, and ensuring that damage to one file does not spread to others are also important. When describing Storage Spaces, Microsoft was silent on how it hoped to tackle these needs. The answer has now been revealed: a new file system, ReFS (from "Resilient File System").

Storage Spaces make it easy to cope from a failed disk, but are no help if a disk is merely producing bad data. The Storage Space will be able to tell you if two mirrored drives differ or if the parity check fails, but have no way of determining which drive is right and which is wrong. Erasures, where the data is missing altogether, can be corrected; errors, where the data is wrong, can only be detected.

ReFS is designed to pick up where Storage Spaces leave off. To protect its internal data structures, file system metadata, and, optionally, user data against corruption, ReFS calculates and stores checksums for the data and metadata. Each piece of information protected by the checksum is fed into a checksum algorithm, and the result is a number, the checksum; in ReFS's case, the checksum is a 64-bit number. Checksum algorithms are designed such that a small change in the input causes a large change in the resulting checksum.

Every time ReFS reads file system metadata (or data that has opted in to the checksum protection) it will compute the checksum for the information it has read, and compare this against the stored value. If the two are in agreement then the data has been read correctly; if they aren't, it hasn't.

This checksum protection guards against a range of problems. When writing, two particular issues are "lost writes," where the data never makes it to disk, and "misdirected writes," where a bug in either the file system driver or the firmware of the drive or its controller causes a write to go to the wrong location on disk. When reading data, the biggest concern is "bit rot"—the corruption of correctly-written data due to failures of the disk's magnetic storage.

This solves the problem of not knowing which side of a mirrored pair is the correct one. When used with a Storage Spaces mirror, ReFS will test the checksums of each side of the mirror independently, and then use this to determine which one is correct and which is not.

To further improve protection against bit rot, ReFS will perform scrubbing: it will periodically read all the data and metadata in a volume, verify the checksums are correct, and if necessary use mirrored copies to repair the bad data.

ReFS is also designed to provide greater protection against power failures during write operations. Windows' current file system, NTFS, performs in-place updates of its data structures and metadata. For example, if a file is renamed, NTFS will read the sector of the drive that contains the filename, calculate a new sector with the new filename, and then write the whole sector back out. This means that a whole sector could be corrupted if the write is interrupted by a power failure, a problem known as "torn writes". Traditionally, this meant that 512 bytes could be damaged; on modern hard drives, that's now increased to 4096 bytes. ReFS will work differently; instead of updating the metadata in-place, it will write new metadata to a different location, preventing damage from torn writes.

Like NTFS, ReFS will also prevent cascading failures. If an uncorrectable problem does occur—corruption of data that isn't mirrored, or has no valid mirrors—ReFS will be able to make a record of the problem and then remove access to the damaged data, without taking the volume offline or interrupting access to any other data on the same volume.

The decision to change file systems is not one to be taken lightly. A bug in a file system can cause catastrophic data loss for millions of people. The two file system implementations with the most real-world testing are both Microsoft's; its NTFS and FAT32 drivers have more users than any other file system drivers in the world. That's not something to be discarded on a whim: the enormous amount of real-world testing means that bugs and unusual corner case situations are more likely to have been found—and fixed—in those file systems than any other.

Microsoft is not discarding these tried and trusted NTFS code entirely with ReFS. The ReFS driver will take parts of the existing NTFS driver, including its API and handling of caching and security, and re-use them. Only the lower-level parts of the driver, the parts concerned with how data is laid out on disk, have changed.

Understandably, Microsoft is taking a conservative approach to rolling out ReFS support. Only Windows Server 8 will include the ReFS; desktop-oriented Windows 8 will stick with NTFS. Just as with Storage Spaces, ReFS will not be usable as a boot drive, either. Future versions of Windows will extend ReFS support to the client, and eventually make it bootable. Windows Server 8 will also have no facility for converting NTFS volumes to ReFS; creating a new volume and copying data will be the only migration path.

More surprisingly, ReFS contains a number of feature regressions relative to NTFS. Most remarkably, it doesn't support hard links, a feature found on NTFS and all UNIX file systems that allows one file to be given multiple names at multiple paths. This is particularly surprising, because Windows uses hard links extensively for its side-by-side storage of different library versions. Using hard links in this way is relatively new to Windows; Windows Vista was the first to do so.

Another new-in-Windows Vista feature, transactional updates to user data, also won't be included. Windows Vista and Windows 7 allow database-like transactions to be made to the file system, wherein a batch of updates to the file system can be made atomically. Per-file encryption and per-file compression also aren't supported in ReFS. Nor are named data streams, handy as these are for working with Mac OS X clients. Storage quotas are also gone.

Not all the missing features are surprising. Two features that exist only for backwards compatibility—generation of short (8.3) filenames, for DOS compatibility, and support for Extended Attributes, for OS/2 compatibility—are removed.

While the backwards compatibility features can safely stay gone forever, it's hard to see ReFS accepted as a full-on NTFS replacement until the other omissions are resolved.

In spite of its limited availability and feature set, Microsoft says that ReFS will be production-ready, and decidedly not a beta, at Windows Server 8's launch. In addition to the re-use of existing code, the company has also tested the new file system extensively, claiming that it has achieved an "unprecedented level of robustness" for a Microsoft file system.

Though Microsoft has continued to improve NTFS in Windows Vista and Windows 7, it has looked increasingly long in the tooth, particularly when compared to Oracle's ZFS and Linux's btrfs. Both of these file systems have offered flexible storage handling, and integrated fault tolerance, advancing the state of the art of mainstream file systems. Storage Spaces go a long way towards providing Windows with comparably capable volume management. ReFS fills most of the remaining gaps, adding a file system structure that's fundamentally more robust than current NTFS.

A test, or "beta", version of the revamped operating system will be unveiled Wednesday in Barcelona, nudging Windows 8 a step closer to its anticipated mass market release in September or October. The company will offer the most extensive look at Windows 8's progress since it released an early version of the system to developers five months ago.

Microsoft has overhauled its gestures in Windows 8 Consumer Preview. A lot of work has been focused on ensuring the relevant mouse and keyboard equivalent of touch gestures work better than the company’s Developer Preview build. There are seven key gestures in the new OS:

System commands and previously used apps: Swiping from the right of the screen using touch will reveal the charms bar with access to system commands. A swipe to the left will bring up the previously used applications. The mouse equivalent is activated by pointing to the lower-right corner of the screen, and keyboard users can use Windows logo + C to open the charms bar.

App commands and swipe to close: swiping from the bottom edge of a screen towards the top will reveal the app bar for Metro style apps, and swiping from the top down allows you to close the app. Mouse users can right click to access app commands and drag apps to the lower edge to close them. Keyboard users can use Windows logo + Z to open the app bar.

Press and hold to learn: Microsoft is surfacing detailed information in Metro apps by using a press and hold gesture. In some cases this will bring up a menu, but the majority of times it will let Windows 8 users surface information without committing to an action. Mouse users can point to an item to see more options, and keyboard users can use the context menu key.

Tap to perform an action: as you would expect, tapping a live tile or an element will launch an action. Mouse users can simply click and keyboard users will be able to use the enter key.

Slide to drag: this gesture is used to scroll through lists and pages, but it can also be used to move an object or for drawing and writing. Mouse users simply point to the bottom of an app and use the scroll bar and keyboard users can dock an active window to the left or right half of the screen using keyboard shortcuts and navigate using the Windows logo + left / right arrow.

Pinch or stretch to zoom: zooming can be used to jump from the beginning, end, or a specific location within a list. You can start zooming by pinching or stretching two fingers on the screen. Mouse users can press the control key while moving the mouse wheel to zoom in and out, and keyboard users can use Windows logo + Minus / Plus keys to zoom in and out.

Rotate to turn: rotating two or more fingers turns an object. You can turn the whole screen by 90 degrees by rotating a physical device. Mouse and keyboard users can rotate objects in a variety of ways depending on how and whether an app supports it.

Continuing with installation or creating bootable media
Once the download is complete, you are presented a choice to continue the installation, or install on another partition. The latter option takes you to advanced setup, and allows you to save an ISO or create a bootable USB drive before completing other advanced setup options. (This is the option you’ll need to choose if you want to dual boot, for example.)

Microsoft has preinstalled a number of Windows Communications apps in the Windows 8 Consumer Preview. Mail, Calendar, People, and Messaging are all present and provide access to the typical Windows Live features found in Windows 7. The metro style applications all have basic functionality, and work as a quick way to access Microsoft's online applications.

The mail application acts as a fully functional email client with access to Exchange, Google, and Hotmail accounts. Windows 8 Consumer Preview users can simply add an account in without any setup, and get access to the powerful functionality of Exchange accounts without the need for Outlook — a big move for Microsoft in what is essentially a core free Mail product. The Messaging application shows no signs of rumored SMS integration but it does provide a simple way to message Facebook and Windows Live Messenger contacts. Similar to Windows Phone, there is also a way to switch accounts in the interface to chat between the different services. Contacts are populated from the People app of Windows 8 for use in Messaging.

Microsoft's Photos application includes access to SkyDrive, Facebook, and Flickr photos. The application will automatically pull in these photos providing you have linked a Windows Live ID to your local Windows 8 account. The same applies to the rest of the preinstalled Windows 8 applications that use Microsoft's online services, they will all open preconfigured. Although the applications are fairly basic right now, we expect their functionality to be extended by the time Windows 8 is ready later this year.