invalid FAT - basic block=-1

Author: sreerajsivadas

filesystem/filesystem.pdf

@@ -177,7 +177,7 @@ \subsection{Structure of FAT}
 	\item \textbf{Block number of basic block :} It contains the block number where the basic block of a file resides in the disk. It occupies one word in the FAT entry.
 \end{enumerate}
 
-
+For an invalid FAT entry, the value for basic block is stored as -1.
 
 \section{Disk Free List}
 \index{Disk Free List}