MFT Tidier

Disclaimer

Please do not email me about this project without reading the disclaimer above.

Introduction

This is a project for with an interest in going deep under the hood. You will have to write this in C probably with some assembler. You will write a utility to tidy the Windows MFT (Master File Table) Basically, each MFT slot keeps track of where the various where the pieces (extents) for one file are. One of the advantages of defragging your files is the there is only one extent per file and easily fits into a single MFT slot. It does not contain any file names, directory names or attributes. That information in contained in the directory.

The Paragon people discontinued their MFT tidier. There is no other.

Why does the MFT need Tidying?

• The table as a whole needs to be defragged. Several commercial defraggers will do that.
• It can sometimes grow far bigger than needs be. It needs to be chopped back. No commercial tool will do that.
• It can contain empty slots. MFTs (Master File Tables) can get full of holes if someone installs and uninstalls software. These need to be compacted out. No commercial tool will do that.
• It needs to be sorted so that the most commonly used slot are near the end. This makes it more efficient for Windows to keep the most active part of the MFT in RAM (Random Access Memory). You have to look in the directory for the last access date, and put recently accessed MFT slots near the end. No commercial tool will do that.

How Does It Work

Ideally it would boot, tidy the MFT by sorting the entries by last-access or last-update time putting the newest at the end, compacting out the deadwood pruning the MFT to just enough to contain current contents, then defrag. Normally windows does not maintain the last-access dates. You can persuade it to with:

For safety, write a complete new MFT, then at the last second flip the pointer(s) over to the new one.

It would allow processing multiple partitions on one reboot (Paragon could not).

If you can get exclusive access to the partition, you don’t need the reboot, but that would mean writing a second version of the utility.

I am not that familiar with the NTFS (New Technology File System) internals. It seems probably you would also have to patch the directory to the new slot numbers.

The thing that makes this project tricky in you are not running under Windows. You running is some very stripped down environment available to boot-time code. You might first write a version that does not require rebooting (for data partitions without open files), then tackle that complication later.

Native Mode

Before windows has booted, the Windows API (Application Programming Interface) is not available. You must use the native core API. Windows itself uses this core API. Your code to run before Windows has booted must be written as a native program.

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