diff --git a/Fat.cpp b/Fat.cpp
new file mode 100644
index 0000000..ec1ead5
--- /dev/null
+++ b/Fat.cpp
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+
+#include <linux/kdev_t.h>
+
+#define LOG_TAG "Vold"
+
+#include <cutils/log.h>
+#include <cutils/properties.h>
+
+#include "Fat.h"
+
+static char FSCK_MSDOS_PATH[] = "/system/bin/fsck_msdos";
+static char MKDOSFS_PATH[] = "/system/bin/newfs_msdos";
+extern "C" int logwrap(int argc, const char **argv, int background);
+extern "C" int mount(const char *, const char *, const char *, unsigned long, const void *);
+
+int Fat::check(const char *fsPath) {
+    bool rw = true;
+    if (access(FSCK_MSDOS_PATH, X_OK)) {
+        LOGW("Skipping fs checks\n");
+        return 0;
+    }
+
+    int pass = 1;
+    int rc = 0;
+    do {
+        const char *args[5];
+        args[0] = FSCK_MSDOS_PATH;
+        args[1] = "-p";
+        args[2] = "-f";
+        args[3] = fsPath;
+        args[4] = NULL;
+
+        rc = logwrap(4, args, 1);
+
+        switch(rc) {
+        case 0:
+            LOGI("Filesystem check completed OK");
+            return 0;
+
+        case 2:
+            LOGE("Filesystem check failed (not a FAT filesystem)");
+            errno = ENODATA;
+            return -1;
+
+        case 4:
+            if (pass++ <= 3) {
+                LOGW("Filesystem modified - rechecking (pass %d)",
+                        pass);
+                continue;
+            }
+            LOGE("Failing check after too many rechecks");
+            errno = EIO;
+            return -1;
+
+        default:
+            LOGE("Filesystem check failed (unknown exit code %d)", rc);
+            errno = EIO;
+            return -1;
+        }
+    } while (0);
+
+    return 0;
+}
+
+int Fat::doMount(const char *fsPath, const char *mountPoint) {
+    int rc;
+    unsigned long flags;
+
+    flags = MS_NODEV | MS_NOEXEC | MS_NOSUID | MS_DIRSYNC;
+
+    /*
+     * Note: This is a temporary hack. If the sampling profiler is enabled,
+     * we make the SD card world-writable so any process can write snapshots.
+     *
+     * TODO: Remove this code once we have a drop box in system_server.
+     */
+    char value[PROPERTY_VALUE_MAX];
+    property_get("persist.sampling_profiler", value, "");
+    if (value[0] == '1') {
+        LOGW("The SD card is world-writable because the"
+            " 'persist.sampling_profiler' system property is set to '1'.");
+        rc = mount(fsPath, mountPoint, (const char *) "vfat", (unsigned long) flags,
+                (const void *) "utf8,uid=1000,gid=1015,fmask=000,dmask=000,shortname=mixed");
+    } else {
+        /*
+         * The mount masks restrict access so that:
+         * 1. The 'system' user cannot access the SD card at all -
+         *    (protects system_server from grabbing file references)
+         * 2. Group users can RWX
+         * 3. Others can only RX
+         */
+        rc = mount(fsPath, mountPoint, "vfat", flags,
+                "utf8,uid=1000,gid=1015,fmask=702,dmask=702,shortname=mixed");
+    }
+
+    if (rc && errno == EROFS) {
+        LOGE("%s appears to be a read only filesystem - retrying mount RO", fsPath);
+        flags |= MS_RDONLY;
+        rc = mount(fsPath, mountPoint, "vfat", flags,
+                   "utf8,uid=1000,gid=1015,fmask=702,dmask=702,shortname=mixed");
+    }
+
+    if (rc == 0) {
+        char *lost_path;
+        asprintf(&lost_path, "%s/LOST.DIR", mountPoint);
+        if (access(lost_path, F_OK)) {
+            /*
+             * Create a LOST.DIR in the root so we have somewhere to put
+             * lost cluster chains (fsck_msdos doesn't currently do this)
+             */
+            if (mkdir(lost_path, 0755)) {
+                LOGE("Unable to create LOST.DIR (%s)", strerror(errno));
+            }
+        }
+        free(lost_path);
+    }
+
+    return rc;
+}
+
+int Fat::format(const char *fsPath) {
+    unsigned int nr_sec;
+    int fd;
+
+    if ((fd = open(fsPath, O_RDWR)) < 0) {
+        LOGE("Error opening disk file (%s)", strerror(errno));
+        return -1;
+    }
+
+    if (ioctl(fd, BLKGETSIZE, &nr_sec)) {
+        LOGE("Unable to get device size (%s)", strerror(errno));
+        close(fd);
+        return -1;
+    }
+    close(fd);
+
+    const char *args[7];
+    int rc;
+    args[0] = MKDOSFS_PATH;
+    args[1] = "-F";
+    if ((nr_sec * 512) <= ((unsigned int) (1024*1024*1024) * 2)) 
+            args[2] = "16";
+    else
+            args[2] = "32";
+
+    args[3] = "-O";
+    args[4] = "android";
+    args[5] = fsPath;
+    args[6] = NULL;
+    rc = logwrap(7, args, 1);
+
+    if (rc == 0) {
+        LOGI("Filesystem formatted OK");
+        return 0;
+    } else {
+        LOGE("Format failed (unknown exit code %d)", rc);
+        errno = EIO;
+        return -1;
+    }
+    return 0;
+}