Add additional documentation

Author: tannewt

Diff for: docs/workflows.md

@@ -19,10 +19,30 @@ The workflow APIs are documented here.
 These USB interfaces are enabled by default on boards with USB support. They are usable once the
 device has been plugged into a host.
 
-### CIRCUITPY drive
+### Mass Storage
 CircuitPython exposes a standard mass storage (MSC) interface to enable file manipulation over a
-standard interface. This interface works underneath the file system at the block level so using it
-excludes other types of workflows from manipulating the file system at the same time.
+standard interface. (This is how USB drives work.) This interface works underneath the file system at
+the block level so using it excludes other types of workflows from manipulating the file system at
+the same time.
+
+CircuitPython 10.x adds multiple Logical Units (LUNs) to the mass storage interface. This allows for
+multiple drives to be accessed and ejected independently.
+
+#### CIRCUITPY drive
+The CIRCUITPY drive is the main drive that CircuitPython uses. It is writable by the host by default
+and read-only to CircuitPython. `storage.remount()` can be used to remount the drive to
+CircuitPython as read-write.
+
+#### CPSAVES drive
+The board may also expose a CPSAVES drive. (This is based on the ``CIRCUITPY_SAVES_PARTITION_SIZE``
+setting in ``mpconfigboard.h``.) It is a portion of the main flash that is writable by CircuitPython
+by default. It is read-only to the host. `storage.remount()` can be used to remount the drive to the
+host as read-write.
+
+#### SD card drive
+A few boards have SD card automounting. (This is based on the ``DEFAULT_SD`` settings in
+``mpconfigboard.h``.) The card is writable from CircuitPython by default and read-only to the host.
+`storage.remount()` can be used to remount the drive to the host as read-write.
 
 ### CDC serial
 CircuitPython exposes one CDC USB interface for CircuitPython serial. This is a standard serial

Diff for: locale/circuitpython.pot

@@ -82,7 +82,7 @@ msgstr ""
 msgid "%q and %q contain duplicate pins"
 msgstr ""
 
-#: ports/atmel-samd/common-hal/audioio/AudioOut.c
+#: shared-bindings/audioio/AudioOut.c
 msgid "%q and %q must be different"
 msgstr ""
 
@@ -154,7 +154,7 @@ msgstr ""
 msgid "%q length must be >= %d"
 msgstr ""
 
-#: py/modsys.c py/objmodule.c py/runtime.c
+#: py/modsys.c py/runtime.c
 msgid "%q moved from %q to %q"
 msgstr ""
 

Diff for: shared-bindings/storage/__init__.c

@@ -97,6 +97,14 @@ MP_DEFINE_CONST_FUN_OBJ_1(storage_umount_obj, storage_umount);
 //| ) -> None:
 //|     """Remounts the given path with new parameters.
 //|
+//|     This can always be done from boot.py. After boot, it can only be done when the host computer
+//|     doesn't have write access and CircuitPython isn't currently writing to the filesystem. An
+//|     exception will be raised if this is the case. Some host OSes allow you to eject a drive which
+//|     will allow for remounting.
+//|
+//|     Remounting after USB is active may take a little time because it "ejects" the drive for one
+//|     query from the host. These queries happen every second or so.
+//|
 //|     :param str mount_path: The path to remount.
 //|     :param bool readonly: True when the filesystem should be readonly to CircuitPython.
 //|     :param bool disable_concurrent_write_protection: When True, the check that makes sure the