Preface:
We are using a Windows-7-Embedded image, for making client-ready copies of our software.
The flow is pretty standard:
Take a blank hard-drive.
Restore an in-house Windows-7-Embedded image on the hard-drive.
Install additional software on-top.
Hard-drive ready!
The Problem:
Sometimes, probably due to system crashes, some configurations that are already configured inside the image - reset.
My current problem is with a 'Disable Write Caching' option on the disk.
In the image, the option is off.
Sometimes, it just resets and turns on.
My Question:
How can I programmatically disable the disk write caching property?
Design Restrictions:
Can run an .exe on startup. The system is mostly c++ so that is that would be the optimal language for a code based solution.
Can run a .bat file.
can run a .vbs file. Not sure which version our current infrastructure are compatible with.
Images (Inside Image -> After Crash):
Clarifications:
Did my research. did not find anything related to windows write caching option in SO or SE as a whole. Did find a bunch of linux related questions.
The system crashes are by-design, at the moment. This is the obvious root cause, but cannot be fixed due to design restrictions and budget issues.
There is a registry setting EnableCache you may try to experiment with. It applies to FAT file systems and setting it to 0 shall theoretically disable disk caching. Though I have not tested it.
Look into:
HKEY_LOCAL_MACHINE\SYSTEM\StorageManager\FATFS or HKEY_LOCAL_MACHINE\SYSTEM\StorageManager\EXFAT
Related
I've been going through the windows documentation for the Dism API with the goal of writing an exe in C++ (or whatever language can accomplish this) that can create a WIM image while running in Windows PE. I found a .NET Wrapper for the Dism API that seems like it might be useful for this purpose, but I'm unsure if a .NET app will successfully run in Windows PE. Overall, my problem is that I don't see a function that can create--and doesn't simply modify--a wim file.
If I didn't care about encapsulating this in an .exe file, the Dism documentation does show how to initially create a wim--which makes me curious why a similar function wouldn't exist within the api. Please advise if the simplest solution is to have my code call a function such as system() within the code.
To summarize, I'm looking for a way to create a wim file programmatically (called from executing an exe file) from within Windows PE.
As always, thank you for the help and advice.
I work on a project that works with DISM in WinPE quite a bit. We configure WinPE with all the .net packages as described here. Then WinPE can be configured to start an application.
I use c#, but you can do managed apps in c++ as I'm sure you know. I find putting c# code into WinPE substantially easier, but that's more a function of my experience, I suppose.
The main way we use to interact with DISM is run a command using System.Diagnostics.Process. The process runs in a separate thread, but the API is simple, and you can wait on (and/or timeout) your process for synchronization purposes. This just uses the DISM command line interface, although you can also use powershell cmdlets if you've added that package to your WinPE image. It may seem like a hacky "interface" from your app to DISM, but it works reliably, and you can keep the process window from showing up on the screen. This makes for a decent asynchronous platform for running bunches of windows imaging utilities, such as DISKPART, DISM and BCDEDIT.
The principal way you'd capture a new image is with DISM /Capture-Image. Sounds like you've already discovered this fact. Lots of options that are somewhat beyond the scope of this q/a, but I hope this gets you on a useful path.
Even though this post is a bit older, here is a possibly still relevant resource for you. Perhaps this one will help.
I've written a small GUI-based tool, project-named WIM-Backup, that uses the Windows Imaging Format (WIM) to create full backups of computer systems (operating system images) within WinPE and then restore them.
The application is hosted on GitHub, is open source, and is offered under the Apache 2.0 license.
In addition, the repository includes an illustrated step-by-step guide to help get it up and running.
Brief summary:
WIM-Backup always requires an external bootable media such as a USB flash drive.
From this drive WinPE is booted to perform a backup or restore to or from an external medium (e.g. a USB hard drive).
On the bootable USB flash drive the WinPE must be set up before (is documented illustrated in the readme).
After completion of the respective operation, a status message is displayed whether the operation was successful or failed.
After restoring a backup, you can boot normally from the destination drive.
Both the backup and restore process are relatively simple (not "rocket science").
To set up the solution, you need about 30 minutes time in the best case due to the necessary downloads (e .g. ADK)
Last but not least: it has a permissive license (non-proprietary) and is open source.
The project can be found here: WIM-Backup
So I need to simulate Isis2 in ns-3. (I am also to modify Isis2 slightly, wrapping it with some C/C++ code since I need at least a quasi real-time mission-critical behavior)
Since I am far from having any of that implemented it would interesting to know if this is a suitable way of conduct. I need to specifically monitor the performance of the consensus during sporadic wifi (ad hoc) behavior.
Would it make sense to virtualize a machine for each instance of Isis2 and then use the tap bridge( model and analyze the traffic in the ns-3 channel?
(I also am to log the events on each instance; composing the various data into a unified presentation)
You need to start by building an Isis2 application program, and this would have to be done using C/CLI or C++/CLI. C++/CLI will be easier because the match with the Isis2 type system is closer. But as I type these words, I'm trying to remember whether Mono actually supports C++/CLI. If there isn't a Mono compiler for C++/CLI, you might be forced to use C# or IronPython. Basically, you have to work with what the compiler will support.
You'll build this and the library on your mono platform and should test it out, which you can do on any Linux system. Once you have it working, that's the thing you'll experiment with on NS/3. Notice that if you work on Windows, you would be able to use C++/CLI (for sure) and then can just make a Windows VM for NS3. So this would mean working on Windows, but not needing to learn C#.
This is because Isis2 is a library for group communication, multicast, file replication and sharing, DHTs and so forth and to access any particular functionality you need an application program to "drive" it. I wouldn't expect performance issues if you follow the recommendations in the video tutorials and the user manual; even for real-time uses the system is probably both fast enough and steady enough in its behavior.
Then yes, I would take a virtual machine with the needed binaries for Mono (Mono is loaded from DLLs so they need to be available at the right virtual file system locations) and your Isis2 test program and run that within NS3. I haven't tried this but don't see any reason it wouldn't work.
Keep in mind that the default timer settings for timeout and retransmission are very slow and tuned for running on Amazon AWS, inside a data center. So once you have this working, but before simulating your wifi setup, you may want to experiment with tuning the system to be more responsive in that setting. I'm thinking that ISIS_DEFAULTTIMEOUT will probably be way too long for you, and the RTDELAY setting may also be too long for you. Amazon AWS is a peculiar environment and what makes Isis2 stable in AWS might not be ideal in a Wifi setting with very different goals... but all of those parameters can be tuned by just setting the desired values in the Environment, which can be done in bash on the line that launches your test program, or using the bash "Export" command.
I'm trying to make a software that backups my entire hard drive.
I've managed to write a code for reading the raw data from hard disk sectors. However, i want to have incremental backups. For that i need to know the changed made to OS settings, file changes, everything.
My question is -
Using FileSystemWatcher and Inotify, will i be able to know every change made to every sector in the hard drive ? (OS settings etc)
I'm coding it in C++ for linux and windows.
(Saw this question on Stackoverflow which gave me some idea)
Inotify is to detect changes while your program is running, I'm guessing that FilySystemWatches is similar.
One way to solve this is to have a checksum on each sector or multiple of sectors, and when making a backup you compare the checksums to the list you have and only backup blocks that have been changed.
The MS Windows FileSystemWatcher mechanism is more limited than Linux's Inotify, but both probably will do what you need. The Linux mechanism provides (optional) notification for file reads, which causes the "access timestamp" to be updated.
However, the weakness from your application's perspective is that all file modifications made from system boot up to your program getting loaded (and unload to shutdown) will not be monitored. Your application might need to look through file modification timestamps of many files to identify changed files, depending on the level of monitoring you are targeting.
Both architectures maintain a timestamp for each file tracking when the file was last accessed. If that being updated is a trigger for a backup notification, the Windows mechanism lacking such notification will cause mismatched behavior on the platforms. Windows' mechanism can also drop notifications due to buffer size limitations. Here is a real gem from the documentation:
Note that a FileSystemWatcher does not raise an Error event when an event is missed or when the buffer size is exceeded, due to dependencies with the Windows operating system. To keep from missing events, follow these guidelines:
Increasing the buffer size with the InternalBufferSize property can prevent missing file system change events.
Avoid watching files with long file names. Consider renaming using shorter names.
Keep your event handling code as short as possible.
At least you can control two out of three of these....
I need to analyse some malware that I have on a vmware image (vmware is a virtual machine), in particular I need to do a full dump of a certain process. I know that vmware,on pausing, writes the whole RAM into a .vmem file. The platform the image is taken of is Windows XP. I know that there are certain tools that do this but they are mostly closed source or don't work for Windows XP. I need it to be done in reasonable time (under one second if that is possible somehow) and to run it from my own C++ program, any help would be really appreciated.
You seem to be asking to interact with processes and their memory from a suspended VM.
Give some forensic tools a shot. This one looks promising:
http://code.google.com/p/volatility/
I am trying to fix an Audacity bug that revolves around portmixer. The output/input level is settable using the mac version of portmixer, but not always in windows. I am debugging portmixer's window code to try to make it work there.
Using IAudioEndpointVolume::SetMasterVolumeLevelScalar to set the master volume works fine for onboard sound, but using pro external USB or firewire interfaces like the RME Fireface 400, the output volume won't change, although it is reflected in Window's sound control panel for that device, and also in the system mixer.
Also, outside of our program, changing the master slider for the system mixer (in the taskbar) there is no effect - the soundcard outputs the same (full) level regardless of the level the system says it is at. The only way to change the output level is using the custom app that the hardware developers give with the card.
The IAudioEndpointVolume::QueryHardwareSupport function gives back ENDPOINT_HARDWARE_SUPPORT_VOLUME so it should be able to do this.
This behavior exists for both input and output on many devices.
Is this possibly a Window's bug?
It is possible to workaround this by emulating (scaling) the output, but this is not preferred as it is not functionally identical - better to let the audio interface do the scaling (esp. for input if it involves a preamp).
The cards you talk about -like the RME- ones simply do not support setting the master or any other level through software, and there is not much you can do about it. This is not a Windows bug. One could argue that giving back ENDPOINT_HARDWARE_SUPPORT_VOLUME is a bug though, but that likely originates from the driver level, not Windows itself.
The only solution I found so far is hooking up a debugger (or adding a dll hook) to the vendor supplied software and looking at the DeviceIOControl calls it makes (those are the ones used to talk to the hardware) while setting the volume in the vendor software. Pretty hard to do this for every single card, but probably worth doing for a couple of pro cards. Especially for Audacity, for open source audio software it's actually not that bad so I can imagine some people being really happy if the volume on their card could be set by it. (at the time we were exclusively using an RME Multiface I spent quite some time in figuring out the DeviceIOControl calls, but in the end it was definitely worth it as I could set the volume in dB for any point in the matrix)