Add new under construction system calls to the readme and change the one for loading files to accomodate them, move the disk parameters to the main namespace in anticipation of restructuring the disk operations with the addition of the new system calls, rewrite parts of system to remove essentially duplicate code, and rewrite the explanation of the file system in the readme.

README.MD

@@ -39,14 +39,11 @@ The input system is inspired by typewriters. Typing a character
 overwrites the cursor location and the erase (=tab) key erases it. The
 space and backspace keys move the cursor.
 
-EttinOS assigns the drives letters from A to D and uses the FAT12 file
-system. The BIOS parameter block sections for hidden and total sectors,
-the entire extended BIOS parameter block, and the directory entry
-sections for file attributes, creation date and time, and access date
-are not supported and are ignored if present: as a result disk labels
-and subdirectories are not supported. Drive letters and file names are
-case-insensitive and the latter follow the 8.3 format. Text files use
-CRLF line endings.
+EttinOS assigns the drives letters from A to D and uses a version of the
+MS-DOS 3.0 FAT12 file system (in actual use since 2.1) without support
+for file attributes and thus disk labels and subdirectories. Drive
+letters and file names are case-insensitive and the latter follow the
+8.3 format. Text files use CRLF line endings.
 
 Drives and files are specified as ([A-D]:) and ([A-D]:)FILENAME.EXT
 respectively. Specifying the current drive, indicated in the prompt, is