Drive and Disk Information

Overview

The library does not have a "drive" concept. Drives are a Windows-centric idea, and they get the wrong answer in many real-world scenarios: UNC paths, Unix mount points, per-user quotas, drives mounted into a subdirectory. Disk-space and file-system metadata is exposed instead on every IAbsoluteDirectoryPath, where it can answer the question for the actual location you care about.

What's Available

Every absolute directory path exposes:

Member Description
AvailableFreeSpace Bytes available to the current user, taking quotas into account.
TotalFreeSpace Bytes free on the volume, ignoring per-user quotas.
TotalSize Total volume size in bytes.
DriveType Fixed, Removable, Network, CDRom, etc.
FileSystem The file system name (e.g. "NTFS", "ext4").
IsUnc true if the path is a UNC path (Windows only). 
IAbsoluteDirectoryPath installDir = appBase.CombineDirectory("data");

Console.WriteLine($"File system : {installDir.FileSystem}");
Console.WriteLine($"Drive type  : {installDir.DriveType}");
Console.WriteLine($"Free space  : {installDir.AvailableFreeSpace:N0} bytes");
Console.WriteLine($"Total size  : {installDir.TotalSize:N0} bytes");
Note

These properties touch the file system on each access. If you'll read more than one in a tight loop, capture them into local variables.

Pre-Flight Free-Space Check

A common installer / writer pattern: before writing data, check that the eventual location will have enough room. The trick is that the eventual location may not exist yet. Walk up to the nearest existing directory and ask there:

IAbsoluteDirectoryPath target = userInstallPath;
IAbsoluteDirectoryPath checkAt = target.GetLastExistingDirectory();

if (checkAt.AvailableFreeSpace < requiredBytes)
    throw new IOException($"Not enough free space at {checkAt.PathDisplay}.");

target.Create();

GetLastExistingDirectory() walks up the path until it finds a directory that exists, which is always somewhere on the volume the new path would land on.

Mounting Points

DirectoryPath.GetMountingPoints() returns the file system roots (drives on Windows, mount points on Unix):

foreach (IAbsoluteDirectoryPath mount in DirectoryPath.GetMountingPoints())
{
    if (mount.DriveType is DriveType.Fixed)
    {
        Console.WriteLine(
            $"{mount.PathDisplay,-6} {mount.FileSystem,-6} " +
            $"{mount.AvailableFreeSpace,15:N0} / {mount.TotalSize,15:N0}");
    }
}

This is the cross-platform equivalent of DriveInfo.GetDrives(), except every entry is a fully usable IAbsoluteDirectoryPath. You can immediately combine it with relative paths, enumerate it, query free space, and so on.

UNC Paths

UNC paths (\\server\share\...) are first-class citizens. All disk-space and file-system properties work on UNC paths the same way they do on local paths:

var share = DirectoryPath.ParseAbsolute(@"\\fileserver\projects\my-app");
share.AvailableFreeSpace;   // works
share.IsUnc;                // true
Important

System.IO.DriveInfo cannot answer questions about UNC paths. If you previously special-cased UNC handling because of DriveInfo limitations, those workarounds can be removed when migrating to this library.

Drive Type and File System

DriveType and FileSystem are useful for selecting a behavior based on the underlying volume:

if (target.DriveType is DriveType.Network)
    options |= FileOptions.WriteThrough;   // skip OS write cache for network shares

if (target.FileSystem.Equals("FAT32", StringComparison.OrdinalIgnoreCase) && payload.Length > 4L * 1024 * 1024 * 1024)
    throw new IOException("Single file would exceed FAT32 4 GB limit.");

Next Steps