Add "intent" field to a snapshot.

[cumulus.git] / doc / format.txt

diff --git a/doc/format.txt b/doc/format.txt
index 5c9d5fa..7449681 100644 (file)
--- a/doc/format.txt
+++ b/doc/format.txt
@@ -122,6 +122,18 @@ Both a checksum and a slice can be used.  In this case, the checksum is
 given first, followed by the slice.  The checksum is computed over the
 original object contents, before slicing.
 
 given first, followed by the slice.  The checksum is computed over the
 original object contents, before slicing.
 

+Special Objects
+---------------
+
+In addition to the standard syntax for objects described above, the
+special name "zero" may be used instead of segment/sequence number.
+This represents an object consisting entirely of zeroes.  The zero
+object must have a slice specification appended to indicate the size of
+the object.  For example
+    zero[0+1024]
+represents a block consisting of 1024 null bytes.  A checksum should not
+be given.
+

 
 FILE METADATA LISTING
 =====================
 
 FILE METADATA LISTING
 =====================