The Compact-Flash Wildcard and
CF Card Software Package User Guide

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C: int Init_File_Heap( uint maxopen_files, uint file_bufsize, xaddr xheap_start, xaddr xheap_end )
4th: Init_File_Heap ( maxopen_files\file_bufsize\xheap_start\xheap_end -- error)
Initializes a heap in the memory region defined by heap_start to heap_end to contain the arrays and buffers used by the file system. All arrays in the specified file heap are dimensioned, and all except the File_Contents buffer are zeroed. This function is typically not called directly by the programmer; rather, it is called via Init_File_IO or Init_File_System functions. See the glossary entry of Init_File_System for the default parameter values passed to this function. FI must point to a 300 byte block of available RAM before this function is called; this initialization is handled by Init_File_IO or Init_File_System. The parameter maxopen_files specifies the maximum number of files that can be open at one time, and file_bufsize indicates the size of a file contents buffer that is available to the user and is also used by the File_Copy and File_Type functions (see File_Contents). A minimum size of 512 bytes (i.e., 1 sector) is enforced on file_bufsize to ensure that File_Copy, File_To_Memory, and File_Type will work properly. The returned error parameter is -1 if the specified heap is too small to accommodate the required arrays and buffers. The heap size must be at least:
    2.5K + [ (1.6K + file_bufsize) * maxopen_files ]
The heap may span multiple contiguous pages.

C: int Init_File_IO( uint maxopen_files, uint file_bufsize, xaddr xheap_start, xaddr xheap_end,
    xaddr xfat_info )
4th: Init_File_IO (maxopen_files\file_bufsize\xheap_start\xheap_end\xfat_info -- error)
Initializes all of the data structures needed by the ATA/FAT file system as described below. Note that the Set_CF_Module must be executed before calling this function. The module number must correspond to the module address set by the module address selection jumpers and the module port (see Table 1 above). See the glossary entry of Init_File_System for the default parameter values passed to this function. The xfat_info parameter must point to a 300 byte block of available RAM in either common memory or paged memory. The xheap_start and xheap_end parameters are the extended addresses that define the boundaries of the heap that contains the arrays and buffers used by the file system. This function calls Init_File_Heap to set up the heap, dimension the required arrays in the heap, and zero all arrays except the File_Contents array. The parameter maxopen_files specifies the maximum number of files that can be open at one time, and file_bufsize indicates the size of a file contents buffer that is available to the user (see File_Contents). A minimum size of 512 bytes (i.e., 1 sector) is enforced on file_bufsize to ensure that File_Copy, File_To_Memory, and File_Type (which use File_Contents) will work properly. The returned error parameter is nonzero if the specified heap is too small to accommodate the required arrays and buffers. The heap size must be at least:
    2.5K + [ (1.6K + file_bufsize) * maxopen_files ]
The heap may span multiple contiguous pages. The returned error parameter is 0 if there are no errors. The error parameter is -1 if the specified heap is too small to accommodate the required arrays and buffers; the error parameter may also equal ERR_NON_DOS_DRIVE or ERR_ATA_READ or ERR_FAIL_ID_DRIVE (see their glossary entries).
Initialization Procedure: This function stores the specified xfat_info as the base address of the master parameter (see the FI glossary entry), sets the hardware control signals to their inactive states, calls Init_File_Heap (see its glossary entry) to configure the heap and dimension the arrays and buffers used by the file system, zeros the CF resource variable at the base of FI and, if there are no heap errors, calls ATA_ID_DRIVE to obtain necessary information about the ATA flash card. Then this function reads the boot sector on the flash disk. The relevant information obtained by these queries is stored in the appropriate data structures for use by the file system routines. This function or Init_File_System should be called any time (that is, after) a new ATA Flash card is placed into the CF Card socket.

C: int Init_File_System( void )
4th: Init_File_System ( -- error )
This is the highest level initialization routine for the ATA/FAT file system. This function calls Init_File_IO with the following parameters:

C: void Link_File_IO( void )
4th: Link_File_IO ( -- )
A do-nothing function included for backward compatibility with prior kernel-resident versions of this software. The legacy kernel-resident version supports only the Memory Interface Board (MIB) hardware.

C: ulong Max_File_Size( void )
4th: Max_File_Size ( -- d.numbytes )
Returns the maximum number of bytes per file for the flash card that was present when Init_File_System or Init_File_IO was performed. The returned value is the product of the implementation-defined maximum of 128 allowed clusters per file times the number of bytes per cluster for the installed flash disk. A "cluster" is a group of sectors (see SECTOR_SIZE) that is allocated at one time by the FAT file system; cluster size is determined when a disk is originally formatted. This function may be called anytime after the file system is initialized to determine the maximum file size that can be managed for a given ATA flash card. Zero is returned if the file system is not initialized. The implementation-defined maximum of 128 clusters per file supports a minimum file size of 64 Kbytes at 1 sector per cluster, which is typical of a 1 MByte card. The maximum file size increases to 512 Kbytes for a typical 10 Mbyte flash disk with 8 sectors/cluster.

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