Section V
                                                                                                              Useful RAM Locations

Address             Description

0054                Current drive number (DRVNUM)                 
0055                Current track search number                 
0056                Current sector search number                
0069-006A           Points to last buffer used for directory search                 
C077                Serial/IEEE listen address (usually $28)                 
O078                Serial/IEEE talk address (usually $48)                 
007A-0091           24 byte table of buffer oointers (2 bytes*12 buffers)       
0092-0093           Points to the command buffer                 
0094-0095           Points to the error buffer                 
00A8                RAM image of the hardware latch @ $A000                 
00B6                Current job number being executed by the controller   
00B7                Number of active drives (O=single / l=dual)                 

4000-40FF           Buffer number 0                 
4100-41FF           Buffer number 1                 
4200-42FF           Buffer number 2                 
4300-43FF           Buffer number 3
4400-44FF           Buffer number 4                     
4500-45FF           Buffer number 5                      
4600-46FF           Buffer number 6                
4700-47FF           Buffer number 7                
4800-48FF           Buffer number 8
4900-49FF           Buffer number 9
4A00-4AFF           Buffer for Drive 0 BAM            
4B00-4BFF           Buffer for Drive 1 BAM                  

4C00-4C0B           Job cue for 12 buffers                 
4C0C-4C17           Track number for the 12 jobs                 
4C18-4C23           Sector number for the 12 jobs                 
4C24                Disk ID. Byte 0 of Drive 0
4C25                Disk ID. Byte 0 of Drive 1
4C26                Disk ID. Byte 1 of Drive 0          
4C27                Disk ID. Byte 1 of Drive 1                
4C28-4C2C           Five byte header image (used after read & before write)     
4C2D                Write protect change flag for drive 0
4C2E                Write protect change flag for Drive 1  
4C2F                Last position of write protect, drive 0                                 
4C30                Last position of write protect, Drive 1                 
4C31-4C32           User vector for NMI interrupt                 
4C35                Sector interleave count (normally 10)    
4C36                Error recovery count (normally 5)                 
4C37                Flag for head "landing". When motor stops, the drive 
                    head normally Goes to track 40. To override this feature 
                    set this byte to a non-zero number.
4C88-4C89           Disk version from Track 18, Sector 0.                 
4CF1                Talk delay byte for serial communications (normally a
                    $0D in the "C64" mode, set to a 01 in the VIC mode).                
4CF2-4CF3           IEEE attention service vector                 
4CF4-4CF5           Serial attention service vector                
4CF6                Maximum track # for both drives +1 (normally 36)

4D00-4DFF           Unused RAM available to user

4E00-4E28           Command buffer (SA=15)       
4E64-4E87           Error message buffer      
4E88                Current physical track number of Drive 0
4E89                Current physical track number of Drive 1
4E8C                Delay count for head step in mS (normally 5)
4EA2                Header block ID byte (normally $08)
4EA5                Next track the current job requests
4EA6                Next sector the current job requests
4EA9                Current job number (0-11)
4EAC                Data block ID byte (normally $07)