+typedef size_t (*disk_page_write_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_t addr, const void *buf, size_t);
+
+/**
+ * Type interface for disk page erase function.
+ * \a page is the page address.
+ * \return true if all is ok, false otherwise.
+ */
+typedef bool (*disk_page_erase_t) (struct BattFsSuper *d, pgcnt_t page);
+
+/**
+ * Type interface for disk deinit function.
+ * \return true if all is ok, false otherwise.
+ */
+typedef bool (*disk_close_t) (struct BattFsSuper *d);
+
+
+typedef uint32_t disk_size_t; ///< Type for disk sizes.
+
+/**
+ * Context used to describe a disk.
+ * This context structure will be used to access disk.
+ * Must be initialized by hw memory driver.
+ */
+typedef struct BattFsSuper
+{
+ disk_open_t open; ///< Disk init.
+ disk_page_read_t read; ///< Page read.
+ disk_page_write_t write; ///< Page write.
+ disk_page_erase_t erase; ///< Page erase.
+ disk_close_t close; ///< Disk deinit.
+
+ pgaddr_t page_size; ///< Size of a disk page, in bytes.
+ pgcnt_t page_count; ///< Number of pages on disk.
+
+ /**
+ * Page allocation array.
+ * This array must be allocated somewhere and
+ * must have enough space for page_count elements.
+ * Is used by the filesystem to represent
+ * the entire disk in memory.
+ */
+ pgcnt_t *page_array;
+
+ /**
+ * Lowest free page counter.
+ * This is the counter of the first availble free page.
+ */
+ mark_t free_start;
+
+ /**
+ * Highest free page counter.
+ * This value is the next to be used to mark a block as free.
+ */
+ mark_t free_next;
+
+ disk_size_t disk_size; ///< Size of the disk, in bytes (page_count * page_size).
+ disk_size_t free_bytes; ///< Free space on the disk.
+
+ /* TODO add other fields. */
+} BattFsSuper;