Windows 8.1 architecture
If you want to truly know how Windows 8.1 works and what makes it tick, you need to dig under the hood. Windows 8.1 doesn’t start from an initialization file. Instead, the operating system uses the Windows Boot Manager to initialize and start the operating system.
The boot environment dramatically changes the way the operating system starts. The boot environment was created by Microsoft to resolve several prickly problems related to boot integrity, operating system integrity, and firmware abstraction. The boot environment is loaded prior to the operating system, making it a pre–operating system environment. As such, the boot environment can be used to validate the integrity of the startup process and the operating system itself before actually starting the operating system.
The boot environment is an extensible abstraction layer that allows the operating system to work with multiple types of firmware interfaces without requiring the operating system to be specifically written to work with these firmware interfaces. Rather than updating the operating system each time a new firmware interface is developed, firmware interface developers can use the standard programming interfaces of the boot environment to allow the operating system to communicate as necessary through the firmware interfaces.
Firmware interface abstraction is the first secret ingredient that makes it possible for Windows 8.1 to work with BIOS-based and EFI-based computers in exactly the same way, and this is one of the primary reasons Windows 8.1 achieves hardware independence.
The next ingredient for hardware independence is Windows Imaging (WIM) format. Microsoft distributes Windows 8.1 on media by using WIM disk images. WIM uses compression and single-instance storage to dramatically reduce the size of image files. Using compression reduces the size of the image in much the same way that zip compression reduces the size of files. Using single-instance storage reduces the size of the image because only one physical copy of a file is stored for each instance of that file in the disk image.
The final ingredient for hardware independence is modularization. Windows 8.1 uses modular component design so that each component of the operating system is defined as a separate, independent unit or module. Because modules can contain other modules, various major features of the operating system can be grouped together and described independently of other major features. Because modules are independent from each other, modules can be swapped in or out to customize the operating system environment.
Windows 8.1 includes extensive support architecture. At the heart of this architecture is built-in diagnostics and troubleshooting. Microsoft designed built-in diagnostics and troubleshooting to be self-correcting and self-diagnosing or, failing that, to provide guidance while you are diagnosing problems.
Windows 8.1 includes network awareness and network discovery features. Network awareness tracks changes in network configuration and connectivity. Network discovery controls a computer’s ability to detect other computers and devices on a network.
Network awareness allows Windows 8.1 to detect the current network configuration and connectivity status, which is important because many networking and security settings depend on the type of network to which a computer running Windows 8.1 is connected. Windows 8.1 has separate network configurations for domain networks, private networks, and public networks and is able to detect the following:
- When you change a network connection
- Whether the computer has a connection to the Internet
- Whether the computer can connect to the corporate network over the Internet
Windows Firewall in Windows 8.1 supports connectivity to multiple networks simultaneously and multiple active firewall profiles. Because of this, the active firewall profile for a connection depends on the type of connection.
If you disconnect a computer from one network switch or hub and plug it into a new network switch or hub, you might inadvertently cause the computer to think it is on a different network, and depending on Group Policy configuration, this could cause the computer to enter a lockdown state in which additional network security settings are applied. As shown in Figure 1-6, you can view the network connection status in the Network And Sharing Center. In Control Panel, under Network And Internet, tap or click View Network Status And Tasks to access this management console.
Figure 1-6 Determine the network state.
Windows 8.1 tracks the identification status of all networks to which the computer has been connected. When Windows 8.1 is in the process of identifying a network, the Network And Sharing Center shows the Identifying Networks state. This is a temporary state for a network that is being identified. After Windows 8.1 identifies a network, the network becomes an Identified Network and is listed by its network or domain name in the Network And Sharing Center.
If Windows 8.1 is unable to identify the network, the network is listed with the Unidentified Network status in the Network And Sharing Center. In Group Policy, you can set default location types and user permissions for each network state, as well as for all networks, by using the policies for Computer Configuration under Windows Settings\Security Settings\Network List Manager Policies.
When you are working with the Network And Sharing Center, you can attempt to diagnose a warning status by using Windows Network Diagnostics—another key component of the diagnostics and troubleshooting framework. To start diagnostics, tap or click Troubleshoot Problems, tap or click Internet Connections, and then tap or click Next. Windows Network Diagnostics then attempts to identify the network problem and provide a possible solution.
The Windows diagnostics and troubleshooting infrastructure offers improved diagnostics guidance, additional error reporting details, expanded event logging, and extensive recovery policies. Although early versions of Windows include some help and diagnostics features, those features are, for the most part, not self-correcting or self-diagnosing. Windows now can detect many types of hardware, memory, and performance issues and resolve them automatically or help users through the process of resolving them. For more information, see the “Working with the automated Help and support system” section in Chapter 8.
Error detection for devices and failure detection for disk drives also are automated. If a device is having problems, hardware diagnostics can detect error conditions and either repair the problem automatically or guide the user through a recovery process. With disk drives, hardware diagnostics can use fault reports provided by disk drives to detect potential failure and alert you before this happens. Hardware diagnostics can also help guide you through the backup process after alerting you that a disk might be failing.
Windows 8.1 can automatically detect performance issues, which include slow application startup, slow boot, slow standby/resume, and slow shutdown. If a computer is experiencing degraded performance, Windows diagnostics can detect the problem and provide possible solutions. For advanced performance issues, you can track related performance and reliability data in the Performance Monitor console, which is an administrative tool.
Windows 8.1 can also detect issues related to memory leaks and failing memory. If you suspect that a computer has a memory problem that is not being automatically detected, you can run Windows Memory Diagnostic manually by completing the following steps:
From Start, type mdsched.exe, and then press Enter. Normally, text that you type on Start is entered into the Apps Search box by default.
Choose whether to restart the computer and run the tool immediately or schedule the tool to run at the next restart, as shown in Figure 1-7.
Figure 1-7 Test memory for problems.
Windows Memory Diagnostic runs automatically after the computer restarts and performs a standard memory test. If you want to perform fewer or more tests, press F1, use the up and down arrow keys to set the Test Mix as Basic, Standard, or Extended, and then press F10 to apply the desired settings and resume testing.
When testing is complete, the computer restarts. The test results will be displayed when you log on.
If a computer crashes because of failing memory and Memory Diagnostic detects this, you are prompted to schedule a memory test the next time the computer is started.