The dump file downloaded by Production Environment, opened with mat, found that there were too many reference objects, which could not be recovered smoothly. I don’t know where to start.
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This is going to be a question with a lot of hypotheticals, but it's been on my mind for a while now and I finally want to get some perspectives on how to tackle this "issue". For the sake of the question, I'll make up an example requirement of how the program I want to make would work on a conceptual level without too many specifics.
The Problem
I want to create a program to keep track of miscellaneous info for files and folders. This miscellaneous info can be anything from comments, authors, to more specific info like the original source of the file (a URL for example), categories, tags, and more. All this info is kept track of in an SQLite database.
Now... how would you create a connection to the file (or folder) to the database? Whatever file is added to the program, the file should continue to operate on an independent level from the program, meaning you should be able to edit, copy, move, rename or do anything else with the file you would usually do with your OS of choice - even deleting it.
You should even be able to archive it, zip it, upload it somewhere or do other things that temporarily or permanently removes the file from your system, without losing the connection to the database. The program itself doesn't actually ever touch the files themselves, unless to generate a new entry in the database, but obviously, there should be some kind of reference in the file to a database entry in the program.
Yes, I know that if you delete the file, you would have a dead entry in the database. For now, just treat this as an unfortunate reality that can't be solved unless you incorporate the file more closely into the program.
Possible solutions and why I decided against them
Reference inside Filename
Probably the most obvious choice, you could just have a reference inside the filename to point to a database entry, for example by including the id at the start of the filename:
#1 my-example-file.txt
#12814 this-is-one-of-many-files.txt
Obviously, that goes against what I established earlier, as you would be restricted from freely renaming the file. You would always have to keep in mind to not mess with the id inside the filename, or else the connection to your program is broken. Unfortunately, that is the best bet I currently have, but I would like to avoid using that approach if possible.
Alternate Data Streams (ADS)
A pretty cool feature I recently discovered that's available on NTFS file systems, ADS allows you to store different streams of data for your files, to grossly simplify it. You could attach a data stream to your file that saves the id for the database entry in the program, and a regular user would never be able to mess directly with that.
However, since this is a feature reserved for specific file systems, there's some ugly side effects to ADS, as you can easily lose that part of the file by:
moving/copying it to a file system that doesn't support ADS, such as the file systems most often used in removable drives
uploading it to a cloud then later downloading it
moving it to another OS that might not support ADS or treats it in an unexpected way
zipping it
Thus I can't really rely on ADS either.
I am confused about how people analyze crash dump files generated by exe/dll files which were protected by VMProtect(3.0 or later). Even though I have the original exe/dll, the map file, and the pdb file, I can not find the original call stack or the crash point in the C++ source code. Does anyone know how to analyze these dump files? I'v got a huge amount of dump files to be handle...
You can use "MiniDump Fixer" to fix minidump files:
https://vmpsoft.com/20111114/minidump-fixer/
I was just reading this https://en.wikipedia.org/wiki/Clustered_file_system#Distributed_file_systems
The definition of a DFS seems to exactly describe Dropbox to me but it isn't in the list of examples, which of course it would be if it was one I think.
So what is different about Dropbox which makes it not fall into this category?
Usually, when talking about distributed file-systems, you expect properties that Dropbox doesn't support. For example, if you and I share a folder, I can create a file called "work.txt" in it and you can create a file "work.txt" in it, and if we do it fast enough (or when we're not syncing with dropbox) we'll have conflicting copies of the same file.
A similar example would be if we both edit the same file concurrently - we'll have conflicting copies, which is something a distributed file system should prevent. In the link you refer to, this is called "Concurrency transparency; all clients have the same view of the state of the file system".
Another example of a property dropbox doesn't support: if my computer fails (e.g., my hard-drive is corrupted) I might lose data that wasn't uploaded to Dropbox. There is a small window in which I think my data was written to the local disk, but if my computer fails, I lose that data.
Lastly, I'm not sure how Dropbox will operate with file locks. For example, MS office takes locks on .doc files, to ensure no one else is working on them at the same time. I don't think Dropbox supports this feature.
I've written a blog post about some of complexities of implementing a distributed file-system, you might find it helpful as well.
How would one go about associating a file type with his application? I know how to read the command line arguments but I am not sure how I can "register" the file extension with Windows. Furthermore, my application is a stand-alone executable, so how would I keep Windows up-to-date on the location of my program?
I did a fair amount of searching and all I could find were old articles that didn't explain everything. How can I create file associations to a stand-alone executable in VB.NET?
Everything is handled by the registry. If you want to make your program self-register it's current location when run see this example.
http://www.codeproject.com/KB/dotnet/System_File_Association.aspx
I've always backed up all my source codes into .zip files and put it in my usb drive and uploaded to my server somewhere else in the world.. however I only do this once every two weeks, because my project is a little big.
Right now my project directories (I have a few of them) contains a hierarchy of c++ files in it, and interspersed with them are .o files which would make backing up take a while if not ignored.
What tools exist out there that will let me just back things up efficiently, conveniently and lets me specify which file types to back up (lots of .png, .jpg and some text types in there), and which directories to be ignored (esp. the build dirs)?
Or is there any ingenious methods out there that people use?
Though not a backup solution, a version control manager on a remote server responds to most of your needs:
only changes are saved, not the whole project
you can filter out what you don't want to save
Moreover, you can create archives of your repository for true backup purposes.
If you want to learn about version control, take a look at Eric Sink's weblog, in particular:
Source Control HOWTO, for the basics of source control
Mercurial, Subversion, and Wesley Snipes for the links to articles on distributed version control systems
I use dropbox, im a single developer developing software. In some projects I work out from my dropbox which means they synchronize every time i build. Other projects i copy the source code there my self. But most important is that i can work on all my computers with dropbox installed on them... works for my simple needs
Agree with mouviciel. If you do not want that, consider rsync or unison to efficiently keep an up-to-date copy, be it on the same or a different machine.