ManagedDrive

English | 中文

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English

A Windows RAM disk manager built on .NET 10 and WinFsp.
Create, mount and manage in-memory volumes that appear as normal drive letters in Explorer.

Features

• Mount multiple RAM disks simultaneously, each with its own drive letter
• Configurable capacity, volume label and read-only flag
• Dynamic memory allocation — disk capacity is a ceiling, not a reservation; memory is consumed only as files are written and released when files are deleted
• Edit a mounted disk — change label, capacity, auto-mount, and image path live without data loss; changing the drive letter or read-only flag remounts the disk
• Optional persistence — save the disk contents to a .mdr image file and restore it on next mount; Save Image is always available and prompts for a file path if none is set
• Auto-mount saved profiles on application startup
• System-tray icon for quick access; minimizes to tray on window close
• Tray icon tooltip — hover to see all mounted disks with live usage percentages
• High-usage warning — system tray notification when a disk exceeds 90% capacity
• Optional start-minimized mode — launch directly to tray without showing the main window
• Temp directory redirection — right-click a disk to set it as the Windows TEMP/TMP directory; reset to the system default from the toolbar, context menu, or tray menu; automatically resets to the system default when the disk is unmounted or remounted; on startup, if TEMP/TMP points to any RAM disk profile a warning is shown — if the disk is not set to auto-mount, TEMP is also automatically reset to the system default; on user-initiated exit (menu button or tray menu), if TEMP/TMP points to any mounted RAM disk the app interrupts the exit, brings the main window to the foreground, and asks for confirmation before resetting and exiting — system-initiated shutdown bypasses this prompt
• NTFS-compatible volume identity — the RAM disk reports its filesystem type as NTFS, making it fully usable as a destination for tools that require an NTFS volume (e.g. WinGet, Windows Update staging, BITS downloads)
• Format disk — right-click a disk and choose Format to delete all files and folders instantly (read-only disks are protected); the context menu is organized into three groups: navigation, configuration, and destructive operations
• System tray menu — quick access to Reset Temp Directory (executes silently with a notification bubble result) and Settings in addition to Show, New Disk, and Exit
• Main window opens centered on the primary screen and is brought to the foreground on startup
• Bilingual UI — English and Simplified Chinese, auto-detected from system locale with manual override in Settings
• About dialog — accessible from the overflow menu; shows the app version and a link to the GitHub repository

Installation

Download the latest MSI from the Releases page and run it. The installer automatically installs WinFsp if it is not already present, and selects the UI language based on your Windows locale (English or Simplified Chinese).

Before repairing or uninstalling: if you have redirected your Windows user temporary directory (TEMP/TMP) to a ManagedDrive RAM disk, reset it to the Windows default first — either from inside the app using Reset to Default Temp Directory, or manually via System Properties → Advanced → Environment Variables. The installer will remind you of this during repair and uninstall.

Prerequisites

Requirement	Notes
Windows 10 / 11 (64-bit)	ARM64 is not currently tested
WinFsp 2.1.25156	Exactly this version must be installed before running ManagedDrive. Install via winget: winget install WinFsp.WinFsp -v 2.1.25156. The managed assembly winfsp-msil.dll is installed to C:\Program Files (x86)\WinFsp\bin\ and is referenced by the project automatically.
.NET 10 SDK	Required to build.

Getting Started

# 1. Install WinFsp 2.1.25156
winget install WinFsp.WinFsp -v 2.1.25156

# 2. Clone the repository
git clone https://github.com/coldhighsun/ManagedDrive
cd ManagedDrive

# 3. Build
dotnet build

# 4. Run
dotnet run --project src/ManagedDrive.App -c Release

Alternatively open ManagedDrive.slnx in Visual Studio 2022+ and press F5.

Solution Structure

ManagedDrive/
├── src/
│   ├── ManagedDrive.Core/          # In-memory file system engine (WinFsp)
│   │   ├── DiskOptions.cs          #   Immutable mount configuration record
│   │   ├── FileNode.cs             #   Single file or directory node
│   │   ├── FileNodeMap.cs          #   Thread-safe path→node dictionary
│   │   ├── MemoryFileSystem.cs     #   FileSystemBase implementation (all WinFsp callbacks)
│   │   ├── RamDisk.cs              #   Mount/unmount lifecycle wrapper
│   │   ├── MountManager.cs         #   Multi-disk manager
│   │   └── DiskImageSerializer.cs  #   Binary persistence (.mdr format)
│   │
│   └── ManagedDrive.App/           # WPF desktop application
│       ├── Localization/           #   ResourceDictionary strings (en-US, zh-CN)
│       ├── Infrastructure/         #   RelayCommand
│       ├── Models/                 #   AppConfiguration, DiskProfile
│       ├── Services/               #   SettingsStore, StartupManager, TempDirResetService
│       ├── ViewModels/             #   MainViewModel, DiskViewModel
│       ├── Views/                  #   CreateDiskDialog, SettingsDialog, ConfirmDialog, AboutDialog, TrayTooltipView
│       ├── MainWindow.xaml(.cs)    #   Main window
│       └── App.xaml(.cs)           #   Startup, tray icon, auto-mount
│
├── tests/
│   └── ManagedDrive.Tests/         # xUnit v3 unit tests (pure-managed code only)
│       ├── FileNodeTests.cs
│       └── FileNodeMapTests.cs
│
└── benchmarks/
    └── ManagedDrive.Benchmarks/    # BenchmarkDotNet sequential read/write throughput benchmarks
        ├── Program.cs
        └── ReadWriteBenchmarks.cs

How It Works

ManagedDrive uses WinFsp (Windows File System Proxy) to present an in-memory directory tree as a real Windows volume. WinFsp ships a signed kernel driver that acts as a bridge; all file I/O is forwarded to MemoryFileSystem, which stores data in .NET byte arrays.

Key classes:

• FileNode — holds Fsp.Interop.FileInfo metadata, a byte[] data buffer, and a security descriptor.
• FileNodeMap — a case-insensitive SortedDictionary<string, FileNode> that maps full paths to nodes, supports paginated child enumeration, and tracks total allocated bytes. Thread-safe via the C# 13 Lock type.
• MemoryFileSystem : FileSystemBase — overrides all 21 required WinFsp callbacks (Create, Open, Read, Write, Rename, CanDelete, ReadDirectoryEntry, etc.) and enforces a configurable capacity ceiling, returning STATUS_DISK_FULL when exceeded; memory is not pre-allocated — each FileNode holds only the bytes actually written.
• RamDisk — composes MemoryFileSystem with a FileSystemHost. The static Create() factory mounts the volume and polls until the drive letter is visible in the OS (up to 2.5 s), then broadcasts SHCNE_DRIVEADD to refresh Explorer. Dispose() unmounts.
• MountManager — thread-safe registry of active RamDisk instances. Fires DiskMounted / DiskUnmounted events.
• DiskImageSerializer — reads/writes .mdr files (full FS state including metadata, ACLs, and file data).

Disk Image Format (.mdr)

A little-endian binary format:

Field	Type	Description
Magic	byte[4]	MDRD
Version	int32	Currently 1
Capacity	uint64	Configured capacity in bytes
VolumeLabel	string	Length-prefixed UTF-8
NodeCount	int32	Number of nodes that follow
Node entries	—	Path, metadata (10 fields), security descriptor, file data

Settings & Persistence

• Settings are stored as JSON at %APPDATA%\ManagedDrive\settings.json.
• Windows startup registration uses HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run (no elevation required).
• Logs are written to {AppPath}\logs\log-.txt with daily rolling and 7-day retention (Serilog).
• Version is derived from git tags (v-prefixed, e.g. v0.1.0) via MinVer.

Performance

Sequential read/write throughput measured with BenchmarkDotNet on:

CPU	Intel Core Ultra 7 255H, 16C/16T, 2.0 GHz base
RAM	32 GB
Disk	Samsung MZVLC512HFJD NVMe SSD (512 GB)
OS	Windows 11 25H2 (Build 26200.7462)
Runtime	.NET 10.0.9 · BenchmarkDotNet 0.15.8

Each benchmark creates or reads a single file via FileStream. Writes use FileOptions.WriteThrough (no OS write-back cache) and reads use FileOptions.SequentialScan.

File Size	Operation	RAM Disk	NVMe SSD	Ratio
4 KB	Write	1.6 MB/s	0.9 MB/s	1.8× faster
4 KB	Read	3.1 MB/s	6.4 MB/s	0.5× slower
1 MB	Write	424 MB/s	87 MB/s	4.8× faster
1 MB	Read	562 MB/s	1,290 MB/s	0.4× slower
64 MB	Write	3,281 MB/s	918 MB/s	3.6× faster
64 MB	Read	1,955 MB/s	3,224 MB/s	0.6× slower

Why are RAM disk reads slower?
Physical disk reads appear fast because the OS page cache keeps recently-written files in DRAM. The RAM disk reads go through WinFsp's kernel–userspace bridge, which adds IPC overhead compared to the direct page-cache path. In workloads where data is written once and read many times from cold cache (e.g. build outputs, temp files that outlive page-cache pressure), the RAM disk will consistently outperform SSD on reads too.

4 KB note: small-file results are dominated by file-open/close syscall overhead, not transfer speed.

Raw latency (DefaultJob mean):

File Size	RamDisk Write	RamDisk Read	NVMe Write	NVMe Read
4 KB	2,440 μs	1,259 μs	4,399 μs	610 μs
1 MB	2,361 μs	1,779 μs	11,446 μs	775 μs
64 MB	19,506 μs	32,746 μs	69,695 μs	19,852 μs

Running Tests

dotnet test tests/ManagedDrive.Tests

Tests cover FileNode (allocation unit alignment, index numbers) and FileNodeMap (CRUD, case-insensitive lookup, child pagination, rename, capacity tracking). Mount/unmount integration tests require the WinFsp driver and must be run manually.

Running Benchmarks

Drive letter R: must be free. WinFsp must be installed.

dotnet run --project benchmarks/ManagedDrive.Benchmarks -c Release

Results are written to BenchmarkDotNet.Artifacts/results/ in the working directory.

Known Issues

Certain installers may fail when TEMP is set to a RAM disk

WinFsp mounts drives in the current user's session device namespace. If an installer is extracted to TEMP and then launched by a system-level process — such as the Windows Package Manager service used by winget — that process operates in the global device namespace and cannot resolve user-session drive letters. Attempting to execute such an installer from a path like Z:\Temp\WinGet\...\setup.exe fails with:

0x800704b3 — The network path was not found / 网络路径键入不正确

Known affected packages include WeChatWin_*.exe (WeChat installer). Not all winget packages are affected — many install without issue.

This is an architectural limitation of WinFsp user-mode file systems and cannot be worked around in user space.

Recommendation: If you encounter installation errors, restore TEMP to the Windows default using the toolbar button in ManagedDrive. ManagedDrive will warn you when you attempt to set a RAM disk as TEMP. On every subsequent startup, if TEMP still points to a RAM disk, a warning is shown again — reset TEMP to the Windows default to stop the recurring prompt.

License

MIT

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中文

基于 .NET 10 和 WinFsp 构建的 Windows RAM 虚拟磁盘管理器。
创建、挂载并管理内存盘，它们在文件资源管理器中以普通驱动器号的形式呈现。

功能特性

• 同时挂载多个 RAM 磁盘，每个磁盘拥有独立的驱动器号
• 可配置容量、卷标和只读标志
• 动态内存分配——磁盘容量为上限而非预分配；内存随文件写入而占用，随文件删除而释放
• 编辑已挂载磁盘——修改卷标、容量、自动挂载和镜像路径无需重挂即可实时生效；更改盘符或只读标志时自动重挂
• 可选持久化——将磁盘内容保存为 .mdr 镜像文件，下次挂载时自动还原；保存镜像功能始终可用，未设置镜像路径时自动弹出选择对话框
• 应用启动时自动挂载已保存的磁盘配置
• 系统托盘图标，关闭窗口时最小化到托盘
• 托盘图标悬浮提示——鼠标悬停时显示所有已挂载磁盘及其实时使用率
• 高用量警告——磁盘使用率超过 90% 时通过系统托盘发出通知
• 可选最小化启动——直接启动到托盘，不显示主窗口
• 临时目录重定向——右键单击磁盘可将其设为 Windows TEMP/TMP 目录；通过工具栏、右键菜单或托盘菜单恢复系统默认值；卸载或重挂时自动恢复为系统默认临时目录；启动时若 TEMP/TMP 指向任一内存盘配置，均会显示警告——若该磁盘未设置自动挂载，还会自动将 TEMP 恢复为系统默认值；用户主动退出（菜单按钮或托盘菜单）时，若 TEMP/TMP 指向任一已挂载内存盘，程序将中断退出、将主窗口带到前台，并由用户确认重置后再退出——系统发送关闭信号时不触发此流程
• NTFS 兼容卷标识——内存盘以 NTFS 文件系统类型上报，可作为需要 NTFS 卷的工具（如 WinGet、Windows Update 暂存、BITS 下载）的目标路径
• 磁盘格式化——右键单击磁盘并选择格式化可立即删除所有文件和文件夹（只读磁盘受保护）；右键菜单按导航、配置、破坏性操作三个分组排列
• 系统托盘菜单——在显示、新建磁盘、退出之外，新增重置临时文件夹（静默执行，结果通过气泡通知反馈）和设置快捷入口
• 主窗口启动时居中显示于主屏幕并置于前台
• 双语界面——中文与英文，根据系统语言自动切换，也可在设置中手动更改
• 关于对话框——可从溢出菜单打开，显示应用版本及 GitHub 仓库链接

安装

从 Releases 页面下载最新的 MSI 安装包并运行。安装程序会在 WinFsp 未安装时自动安装，并根据 Windows 系统语言自动选择界面语言（中文或英文）。

修复或卸载前请注意： 如果您已将 Windows 用户临时目录（TEMP/TMP）重定向到 ManagedDrive 内存盘，请先将其恢复为系统默认值——在应用内使用恢复默认用户临时文件夹功能，或手动在「系统属性」→「高级」→「环境变量」中修改。安装程序在执行修复和卸载时会提示您完成此操作。

环境要求

要求	说明
Windows 10 / 11（64 位）	暂未测试 ARM64
WinFsp 2.1.25156	必须安装此特定版本。可使用 winget 安装：winget install WinFsp.WinFsp -v 2.1.25156。托管程序集 winfsp-msil.dll 将安装至 C:\Program Files (x86)\WinFsp\bin\，项目会自动引用。
.NET 10 SDK	编译所需。

快速开始

# 1. 安装 WinFsp 2.1.25156
winget install WinFsp.WinFsp -v 2.1.25156

# 2. 克隆仓库
git clone https://github.com/coldhighsun/ManagedDrive
cd ManagedDrive

# 3. 编译
dotnet build

# 4. 运行
dotnet run --project src/ManagedDrive.App -c Release

或者在 Visual Studio 2022+ 中打开 ManagedDrive.slnx 并按 F5。

解决方案结构

ManagedDrive/
├── src/
│   ├── ManagedDrive.Core/          # 内存文件系统引擎（WinFsp）
│   │   ├── DiskOptions.cs          #   不可变挂载配置记录
│   │   ├── FileNode.cs             #   单个文件或目录节点
│   │   ├── FileNodeMap.cs          #   线程安全的路径→节点字典
│   │   ├── MemoryFileSystem.cs     #   FileSystemBase 实现（所有 WinFsp 回调）
│   │   ├── RamDisk.cs              #   挂载/卸载生命周期封装
│   │   ├── MountManager.cs         #   多磁盘管理器
│   │   └── DiskImageSerializer.cs  #   二进制持久化（.mdr 格式）
│   │
│   └── ManagedDrive.App/           # WPF 桌面应用程序
│       ├── Localization/           #   ResourceDictionary 字符串（en-US、zh-CN）
│       ├── Infrastructure/         #   RelayCommand
│       ├── Models/                 #   AppConfiguration、DiskProfile
│       ├── Services/               #   SettingsStore、StartupManager、TempDirResetService
│       ├── ViewModels/             #   MainViewModel、DiskViewModel
│       ├── Views/                  #   CreateDiskDialog、SettingsDialog、ConfirmDialog、AboutDialog、TrayTooltipView
│       ├── MainWindow.xaml(.cs)    #   主窗口
│       └── App.xaml(.cs)           #   启动、托盘图标、自动挂载
│
├── tests/
│   └── ManagedDrive.Tests/         # xUnit v3 单元测试（仅纯托管代码）
│       ├── FileNodeTests.cs
│       └── FileNodeMapTests.cs
│
└── benchmarks/
    └── ManagedDrive.Benchmarks/    # BenchmarkDotNet 顺序读写吞吐量基准测试
        ├── Program.cs
        └── ReadWriteBenchmarks.cs

工作原理

ManagedDrive 使用 WinFsp（Windows 文件系统代理）将内存目录树呈现为真实的 Windows 卷。WinFsp 附带一个已签名的内核驱动程序作为桥接层；所有文件 I/O 均转发至 MemoryFileSystem，后者将数据存储在 .NET 字节数组中。

核心类：

• FileNode — 持有 Fsp.Interop.FileInfo 元数据、byte[] 数据缓冲区及安全描述符。
• FileNodeMap — 不区分大小写的 SortedDictionary<string, FileNode>，将完整路径映射到节点，支持分页子节点枚举，并追踪已分配字节总量。通过 C# 13 Lock 类型保证线程安全。
• MemoryFileSystem : FileSystemBase — 覆写全部 21 个所需的 WinFsp 回调（Create、Open、Read、Write、Rename、CanDelete、ReadDirectoryEntry 等），并强制执行可配置的容量上限，超出时返回 STATUS_DISK_FULL；内存不预分配——每个 FileNode 仅保留实际写入的字节数。
• RamDisk — 组合 MemoryFileSystem 与 FileSystemHost。静态工厂方法 Create() 挂载卷，并轮询直至驱动器号在系统中可见（最长 2.5 秒），随后向资源管理器广播 SHCNE_DRIVEADD。Dispose() 执行卸载。
• MountManager — 线程安全的活动 RamDisk 实例注册表，提供 DiskMounted / DiskUnmounted 事件。
• DiskImageSerializer — 读写 .mdr 文件（保存完整文件系统状态，包含元数据、ACL 和文件数据）。

磁盘镜像格式（.mdr）

小端序二进制格式：

字段	类型	说明
魔数	byte[4]	MDRD
版本	int32	当前为 1
容量	uint64	配置的容量（字节）
卷标	string	长度前缀 UTF-8
节点数	int32	后续节点数量
节点条目	—	路径、元数据（10 个字段）、安全描述符、文件数据

配置与持久化

• 配置以 JSON 格式存储于 %APPDATA%\ManagedDrive\settings.json。
• 开机自启通过 HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run 注册表项实现（无需提升权限）。
• 日志写入 {AppPath}\logs\log-.txt，每日滚动，保留 7 天（Serilog）。
• 版本号由 MinVer 从 git 标签派生（v 前缀，例如 v0.1.0）。

性能基准

使用 BenchmarkDotNet 测量顺序读写吞吐量，测试环境：

CPU	Intel Core Ultra 7 255H，16C/16T，基础频率 2.0 GHz
内存	32 GB
磁盘	Samsung MZVLC512HFJD NVMe SSD（512 GB）
系统	Windows 11 25H2（Build 26200.7462）
运行时	.NET 10.0.9 · BenchmarkDotNet 0.15.8

每个 benchmark 通过 FileStream 对单个文件进行创建或读取操作。写入使用 FileOptions.WriteThrough（禁用操作系统写回缓存），读取使用 FileOptions.SequentialScan。

文件大小	操作	内存盘	NVMe SSD	倍率
4 KB	写入	1.6 MB/s	0.9 MB/s	快 1.8×
4 KB	读取	3.1 MB/s	6.4 MB/s	慢 0.5×
1 MB	写入	424 MB/s	87 MB/s	快 4.8×
1 MB	读取	562 MB/s	1,290 MB/s	慢 0.4×
64 MB	写入	3,281 MB/s	918 MB/s	快 3.6×
64 MB	读取	1,955 MB/s	3,224 MB/s	慢 0.6×

为何内存盘读取反而更慢？
物理磁盘的读取速度之所以快，是因为操作系统页面缓存将最近写入的文件保留在 DRAM 中。内存盘的读取则需要经过 WinFsp 的内核–用户态桥接，引入了额外的 IPC 开销，比直接走页面缓存路径更慢。在数据写入一次、多次读取且页面缓存已失效的场景下（如构建产物、临时文件），内存盘的读取性能同样会超越 SSD。

4 KB 说明： 小文件结果主要受文件打开/关闭的系统调用开销主导，不反映实际传输速率。

原始延迟（DefaultJob 均值）：

文件大小	内存盘写入	内存盘读取	NVMe 写入	NVMe 读取
4 KB	2,440 μs	1,259 μs	4,399 μs	610 μs
1 MB	2,361 μs	1,779 μs	11,446 μs	775 μs
64 MB	19,506 μs	32,746 μs	69,695 μs	19,852 μs

运行测试

dotnet test tests/ManagedDrive.Tests

测试覆盖 FileNode（分配单元对齐、索引编号）和 FileNodeMap（增删改查、大小写无关查找、子节点分页、重命名、容量追踪）。挂载/卸载集成测试需要 WinFsp 驱动程序，须手动运行。

运行基准测试

驱动器号 R: 须处于空闲状态，且已安装 WinFsp。

dotnet run --project benchmarks/ManagedDrive.Benchmarks -c Release

结果将写入工作目录下的 BenchmarkDotNet.Artifacts/results/。

已知问题

将 TEMP 设为内存盘后，某些安装包可能报错

WinFsp 将驱动器挂载在当前用户的会话设备命名空间中。若安装包被解压到 TEMP 后由系统级进程启动（例如 winget 所使用的 Windows 软件包管理器服务），该进程运行于全局设备命名空间，无法解析用户会话级别的驱动器号。尝试从 Z:\Temp\WinGet\...\setup.exe 之类的路径执行安装程序时，会报错：

0x800704b3 — 网络路径键入不正确 / The network path was not found

已知受影响的安装包包括 WeChatWin_*.exe（微信安装程序）。并非所有 winget 包都受影响——大多数包可正常安装。

这是 WinFsp 用户态文件系统的架构性限制，无法在用户空间层面绕过。

建议： 如遇安装报错，可通过 ManagedDrive 工具栏的按钮将 TEMP 恢复为 Windows 默认值。每次将内存盘设置为临时目录时，ManagedDrive 均会弹出警告提示。此后每次启动，只要 TEMP 仍指向内存盘，警告便会再次弹出——将 TEMP 恢复为 Windows 默认值后即可停止重复提示。

许可证

MIT