Basic working SD card.'

src/storage/storage_config.h

@@ -97,3 +97,18 @@
 // Maximum directory depth printed during the recursive boot listing. Guards
 // the StorageTask stack against pathological directory nesting.
 #define STORAGE_LIST_MAX_DEPTH   10
+
+// --- Write-speed estimation -------------------------------------------------
+
+// Path of the temporary scratch file used to measure write throughput. It is
+// created, written, measured, then deleted, so it never appears in listings.
+#define STORAGE_SPEED_MEASURE_PATH   STORAGE_MOUNT_POINT "/.writespeed.tmp"
+
+// Size of the scratch file written per measurement (bytes).
+#define STORAGE_SPEED_MEASURE_BYTES       (0.5 * 1024 * 1024)
+
+// How often to re-measure write speed (ms). This is a bring-up ESTIMATE only:
+// it writes STORAGE_SPEED_MEASURE_BYTES to the card on every tick. Once real
+// logging exists, throughput should be derived from actual logging writes and
+// this benchmark disabled by setting the interval to 0 (measure once at boot).
+#define STORAGE_SPEED_MEASURE_INTERVAL_MS 0