Update Readme

README.md

@@ -1,6 +1,21 @@
 # SerialFlash
 
-Use SPI Flash memory with a filesystem-like interface.
+SerialFlash provides low-latency, high performance access to SPI Flash memory with a filesystem-like interface.  Familiar file-based functions, similar to the SD library, are used to access data.
+
+In-progress file write and erase operations do NOT block read access on other files.  SerialFlash automatically allocates files with Flash page and sector awareness, and supports suspending in-progress write and erase operations, to minimize read latency even while the Flash memory is "busy" writing data.
+
+Performance oriented design does impose some usage limitations.  Files are created with a fixed size which can never change or grow.  Once created, files can not be renamed or deleted (except for erasing the entire chip).  Files begin with all bytes erased (255).  Each byte may be written only once.  Files created as erasable may be fully erased, to allow new data to be written.  Best performance is achieved by writing in 256 byte chunks, though individual bytes may be written.
+
+
+## Hardware Compatibility
+
+Winbond W25Q128FV is the only chip actually tested so far.
+
+Spansion and Micron SPI Flash chip testing is planned...
+
+TODO: add a list of chips, with verified, should work, or unsupported status.
+
+SerialFlash automatically detects SPI Flash chip type and capacity to automatically handle differences between supported chips.
 
 ## Accessing Files
 
@@ -19,7 +34,7 @@ Use SPI Flash memory with a filesystem-like interface.
 
     file.size();
     file.position()
-    file.seek();
+    file.seek(number);
     
 ### Write Data