5440



     (one), it indicates that the sector associated is in use.

5440           1540           DOS
     DUP.SYS initialization address. Beginning of mini-DOS; the
     RAM-resident portion of DUP. Used for the same purpose in K-
     DOS.

5446,5450      1546,154A      ....
     Contains the location (LSB/MSB) of the DOS VEC (location 10;
     $A). This is the pointer to the address BASIC will jump to when
     DOS is called.

5533           159D           DUPFLG
     Flag to test if DUP is already resident in memory. Zero equals
     DUP is not there.

5534           159E           OPT
     Used to store the value of the disk menu option chosen by the
     user.

5535           159F           LOADFLG
     If this location reads 128, then a memory file (MEM.SAV) file
     doesn't have to be loaded.

5540           15A4           SFLOAD
     Routines to load a MEM.SAV file if it exists.

5888           1700           USRDOS
     Listed in the DUP.SYS equates file but never explained in the
     listings.

5899           170B           MEMLDD
     Flags that the MEM.SAV file has been loaded. Zero means it has
     not been loaded.

5947           173B           ....
     The MEM.SAV (MEMSAVE) file creation routines begin here.
     They start with the file name MEM.SAV stored in ATASCII
     format. The write routines begin at MWRITE, 5958 ($1746). The
     DOS utility MEMSAVE copies the lower 6000 bytes of memory to
     disk to save your BASIC program from being destroyed when
     you call DOS, which then loads DUP.SYS into that area of
     memory.

6044,6045      179C-179D      INISAV
     DOSINI (see location 12, 13; $C, $D) vector save location. Entry
     point to DOS on a call from BASIC.

6046           179E           MEMFLG
     Flag to show if memory has been written to disk using a
     MEM.SAV file.