In the past, I used to worry about optimizing the startup time of my Windows 7 system. For this reason, I also bought a solid-state hard disk and a motherboard that can do Smart Cache for optimization. After that, I often used the security guard 360 startup time optimization as an evaluation. The optimized computer can start the system in 17 seconds and display 99% of the computer in the Security Guard 360, which can't help but float. However, the laptop used in recent work upgraded the Windows 8 RTM version for work reasons, but was surprised to find that on my big black Thinkpad W520, the startup time is 7 seconds, no mistake, it is really amazing 7 seconds!! Compare the Mac Air in the home that was also started with SSD and even better. So what exactly is hidden in Windows 8? Let's take a closer look!
I wonder if everyone has been bothered to optimize the startup time? Smart you may use the way I used in the past - sleep mode, but This approach is clearly due to the need to maintain a power-on state to maintain a memory state or is not conducive to the life of the laptop battery or to the desktop or power. Windows 8 came in order to meet our efficient and fast cold start. In fact, in Windows 7, the boot process has been properly optimized and improved, such as parallel loading of device drivers and service startup, but Windows 8 is clearly a step further, specifically Windows 8 innovative combination of cold boot and sleep mode To speed up the startup process.
So what are the steps involved in the startup and shutdown process in Windows 7?
A complete shutdown process includes:
Selecting the close button in the Start menu or pressing the power button or the application by calling the API Start shutdown with ExitWindowsEx() or InitiateShutdown().
The Windows system broadcasts shutdown information to the running application, giving them the opportunity to save active data and settings status; the application can also request a little extra time.
Windows will shut down each logged in user session.
The Windows system sends the system shutdown information to all services and informs that the shutdown process has started, and then shuts it down in an orderly manner. The shutdown process is a parallel stop service, which is serially closed for services with dependencies. If the service does not respond, the system will force the shutdown.
The system will also tell all devices to turn them off.
Windows shuts down its own system session (session 0)
Windows system flushes all pending data to the hard drive and ensures full save.
The Windows system notifies the underlying power module to shut down through the ACPI power interface.
For the boot process of the system? (I will also discuss in the future diskless SAN Boot boot Windows Server 2012 blog)
After pressing the power button, the PC firmware starts the boot self-test process (everyone Well-known POST) and load firmware settings. At the end of this pre-boot process, a valid system disk is detected to continue. (Of course we need to set the boot order after detecting the hardware in the BIOS.)
Firmware's embedded boot program reads the master boot record (MBR) and then starts Bootmgr.exe. Bootmgr.exe finds and starts the Windows loader (Winload.exe) on the Windows boot partition.
Loading the basic drivers needed to start the Windows kernel and then the Windows kernel program starts running, during which the system registry hive is loaded and the driver labeled BOOT_START is attached to memory.
The Windows kernel passes control to the Session Manager process (Smss.exe) to initialize the system session, then load and start devices and drivers that are not marked as BOOT_START.
Winlogon.exe starts, displays the user login screen, the Service Control Manager starts the service, and the corresponding Group Policy script runs. When a user logs in, Windows creates a session for that user.
Explorer.exe starts, the system will create an initialization desktop and display its Desktop Window Manager (DWM) process.
From the above shutdown process, you can find that the system needs to close all user sessions and kernel sessions, shut down the services and devices and then shut down completely.
The key change that Windows 8 can get up to quickly is that
user sessions are turned off in Windows 8, but the kernel session is no longer closed but handled in a flexible sleep mode. Compared with the full sleep mode, because the application uses a lot of memory pages, the relative sleep data of the system session 0 is actually much smaller, which will greatly reduce the time that the memory used for hibernation is written back to the disk. Hibernation means that the file written to disk (hiberfil.sys) effectively saves the system state and memory content information, and then reads and restores the contents back to memory. The cold boot of Windows 8 uses this technique, and it takes much faster to read the hibernation file and reinitialize the driver, which is a significant 30-70% improvement on most hosts. This is also easier to see, smart people look at you know:
The speed of recovery from sleep mode is obviously much faster than reinitialization recovery (this is not the reason why we can choose to sleep before speculation). In addition, Windows 8 also adds multi-stage recovery features, similar to the distributed job disassembly of stand-alone systems, for example, if you are an i5 or i7 quad-core host will take full advantage of all the kernel concurrently read and decompress hibernate Hibernate files, you must know Decompression is still more CPU-intensive; this feature has also been greatly improved for us to restore the system from hibernation!
Also worth mentioning how to treat hibernation files, use dir /s in Windows 8 system /ah hiberfile.sys Maybe you will find this is quite a big one. The default is 75% of physical memory as the size of the hibernation file. Basically, it is the size reserved for the state data written by the system when it enters the sleep state. In fact, as a quick start, it is usually only 10 to 15% of physical memory (depending on driver, service, and other factors).
Another important feature of Windows 8's quick start is that although this method does not fully enumerate all "plug and play" device drivers, the fast drive mode still initializes the driver. Therefore, the cold start in the quick start mode can still cope with the change of the hardware environment as before. Of course, if you have the conditions to use SSD to quickly start the effect will be more obvious, you also know that even reading a small number of dormant files SSD is more powerful than mechanical hard disk.
There is another one worth mentioning. In fact, if you have a PC that is not old, then of course the boot is faster with the old BIOS. The new UEFI (Unified Extensible Firmware Interface) BIOS is still faster. A lot of. UEFI will initialize the CPU and memory first after power-on. Unlike the BIOS, the loading and initialization of other devices will be processed in parallel, which will greatly improve the startup speed of the system. Of course, most motherboards now support UEFI mode:)
Finally, check if your Windows 8 has started this function, of course, the default should be open:
Run at the command line Powercfg /a, you can see that my system has enabled the fast start function.
The control panel can also be set and viewed:
At the end of the description, you may know that you can disable hibernation and reclaim disk space by running the powercfg /hibernate off command, but see the previous introduction. You may understand this in the Quick Start section, not only will you disable the hibernate and the Quick Start feature will be lost. If you want to go directly to the startup state of Windows 7
, you can run shutdown /s /full /t 0 to shut down or choose to restart from the graphical interface will trigger an old cold boot process, but why should you go back? Br>