● File system mounted. Active write buffer is holding uncommitted directory updates.
Host OS Page Cache (RAM)
Dirty Write Buffers 8 / 32 blocks
USB 3.2
External SSD / Flash Media
NAND Flash Sectors (FTL) 24 Committed
Idle / Free
Dirty RAM (Pending Flush)
In-Flight Flashing
Clean / Committed
Corrupted Block / Zero-Byte
Directory / Superblock

File System Integrity & Cluster Map

Diagnostic Scan: RUNNING
File / Cluster Target Target Size Committed Blocks Pending Cache Integrity Status
Sector LBA 0x00000000 - 0x0000000F (Volume Boot Record & File Allocation Table) Clean Mount Signature [0x55AA]
00000000: EB 76 90 45 58 46 41 54 20 20 20 00 00 00 00 00 .v.EXFAT ..... 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000040: 00 00 08 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA ..............U.

Why Write Caching Exists

Flash memory (NAND) writes are orders of magnitude slower than system RAM. Operating systems immediately return control to applications by storing writes in the kernel Page Cache (RAM) and writing to disk in asynchronously batched blocks. If you pull the drive before the write pipeline flushes, data that the OS reported as "saved" actually vanishes.

exFAT vs Journaled Filesystems

Most flash drives use exFAT for cross-platform compatibility between Windows and Mac. However, exFAT lacks journaling! When unplugged during a directory tree update, its File Allocation Table is desynchronized with data clusters, causing orphaned clusters, missing directories, or zero-byte video headers.

What "Safely Eject" Actually Does

Safe Removal is not just polite UI etiquette. Clicking "Eject" triggers a SCSI SYNCHRONIZE CACHE or NVMe Flush command, forces all dirty kernel buffers to physically write to NAND flash, marks the volume clean bit, and powers down the controller interface so no voltage spikes hit the flash translation layer (FTL).

Enjoy this tool? Build your own with Super