Index: /trunk/include/iprt/formats/fat.h
===================================================================
--- /trunk/include/iprt/formats/fat.h	(revision 66575)
+++ /trunk/include/iprt/formats/fat.h	(revision 66575)
@@ -0,0 +1,80 @@
+/* $Id$ */
+/** @file
+ * IPRT, File Allocation Table (FAT).
+ */
+
+/*
+ * Copyright (C) 2017 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+#ifndef ___iprt_formats_fat_h
+#define ___iprt_formats_fat_h
+
+#include <iprt/types.h>
+#include <iprt/assert.h>
+
+#pragma pack(1)
+
+/** @name FAT Media byte values
+ * @remarks This isn't as simple as it's made out to be here!
+ * @{ */
+#define FATBPB_MEDIA_FLOPPY_8           UINT8_C(0xe5)
+#define FATBPB_MEDIA_FLOPPY_5_DOT_25    UINT8_C(0xed)
+#define FATBPB_MEDIA_FLOPPY_3_DOT_5     UINT8_C(0xf0)
+/** @} */
+
+typedef struct FATBPB
+{
+    /** 0x0b / 0x00: The sector size in bytes. */
+    uint16_t        cbSector;
+    /** 0x0d / 0x02: Number of sectors per cluster. */
+    uint8_t         cSectorsPerCluster;
+    /** 0x0e / 0x03: Number of reserved sectors before the first FAT. */
+    uint16_t        cReservedSectors;
+    /** 0x10 / 0x05: Number of FATs. */
+    uint8_t         cFats;
+    /** 0x11 / 0x06: Max size of the root directory (0 for FAT32). */
+    uint16_t        cMaxRootDirEntries;
+    /** 0x13 / 0x08: Total sector count, zero if 32-bit count is used. */
+    uint16_t        cOldTotalSectors;
+    /** 0x15 / 0x0a: Total sector count, zero if 32-bit count is used. */
+    uint16_t        bMedia;
+} FATBPB;
+
+typedef struct FATBOOTSECTOR
+{
+    /** 0x000: DOS 2.0+ jump sequence. */
+    uint8_t         abJmp[3];
+    /** 0x003: OEM name (who formatted this volume). */
+    char            achOemName[8];
+    /** 0x00b: The BIOS parameter block.
+     * This varies a lot in size. */
+    union
+    {
+
+    } Bpb;
+} FATBOOTSECTOR;
+typedef FATBOOTSECTOR *PFATBOOTSECTOR;
+typedef FATBOOTSECTOR const *PCFATBOOTSECTOR;
+
+#pragma pack()
+
+#endif
+
Index: /trunk/include/iprt/vfslowlevel.h
===================================================================
--- /trunk/include/iprt/vfslowlevel.h	(revision 66574)
+++ /trunk/include/iprt/vfslowlevel.h	(revision 66575)
@@ -188,5 +188,5 @@
 
     /**
-     * Checks whether a given range in the underlying medium
+     * Optional entry point to check whether a given range in the underlying medium
      * is in use by the virtual filesystem.
      *
@@ -197,6 +197,5 @@
      * @param   pfUsed      Where to store whether the given range is in use.
      */
-    DECLCALLBACKMEMBER(int, pfnIsRangeInUse)(void *pvThis, RTFOFF off, size_t cb,
-                                             bool *pfUsed);
+    DECLCALLBACKMEMBER(int, pfnIsRangeInUse)(void *pvThis, RTFOFF off, size_t cb, bool *pfUsed);
 
     /** @todo There will be more methods here to optimize opening and
@@ -549,5 +548,5 @@
      * @sa      RTFileRemove, RTDirRemove, RTSymlinkRemove.
      */
-    DECLCALLBACKMEMBER(int, pfnUnlinkEntry)(void *pvThis, const char *pszEntry, RTFMODE fType, PRTVFSDIR phVfsDir);
+    DECLCALLBACKMEMBER(int, pfnUnlinkEntry)(void *pvThis, const char *pszEntry, RTFMODE fType);
 
     /**