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Annotation of driverkit/notes/FloppyParams, revision 1.1

1.1     ! root        1:                        Floppy disk param notes
        !             2:                        
        !             3: Current driver
        !             4: 
        !             5: fd_attach_com {
        !             6: 
        !             7:        recal, abort if error (do some retries);
        !             8:        get status (MID, WP, etc.);
        !             9:        get struct fd_disk_info (fd_format_info.fd_disk_info) via MID;
        !            10:        for(fd_format_info.density_info.density= 4 to 1) {
        !            11:                seek to read_id_cyl (should ++);
        !            12:                if read_id works
        !            13:                        goto found_dens;
        !            14:        }
        !            15:        
        !            16:     found_dens:
        !            17:        if density = none {
        !            18:                disk unformatted:
        !            19:                
        !            20:                // get defaults for density, sect_size
        !            21:                density = fd_format_info.fd_disk_info.max_density; 
        !            22:                sect_size = fd_get_sectsize_info(density)[0].sect_size
        !            23:                set_density_info(density); 
        !            24:                set_sector_size(sect_size);
        !            25:                return;
        !            26:        }
        !            27:        
        !            28:        mark disk as formatted to allow reading;
        !            29:        for each legal sect_size for the fd_sectsize_info for this density {
        !            30:                set_sector_size(sect_size);
        !            31:                do a retry loop {
        !            32:                        read(test_sector++);
        !            33:                        if good
        !            34:                                goto found_sect_size;
        !            35:                }               
        !            36:        }
        !            37:        mark disk unformatted;
        !            38:        return;
        !            39:        
        !            40:     found_sect_size:
        !            41:        return good;
        !            42:        
        !            43: }
        !            44: 
        !            45: set_density_info(int density) 
        !            46: {
        !            47:        // don't have to save sect_size; sectsize_info won't change by the 
        !            48:        // time we need it...
        !            49:        
        !            50:        save current sect_size from fd_format_info.sectsize_info.sect_size;
        !            51:        find fd_density_info for spec'd density, write it to
        !            52:                fd_format_info.density_info;
        !            53:        set_sect_size(saved_sect_size);
        !            54:        if density == none
        !            55:                mark disk unformatted;
        !            56: }
        !            57: 
        !            58: set_sect_size(sect_size) 
        !            59: {
        !            60:        validate that this sect_size is legal for current 
        !            61:                fd_format_info.density_info;
        !            62:        set fd_format_info.sectsize_info;
        !            63:        set disk formatted;
        !            64: }
        !            65: 
        !            66: .........................
        !            67: 
        !            68: what are all of these weird structs?
        !            69: 
        !            70: fd_disk_info (fd_disk_info_t): fd_extern.h
        !            71:        maps media_id to tracks_per_cyl and num_cylinders.
        !            72:        One per media_id in fdDiskInfo[].
        !            73: 
        !            74: fd_sectsize_info (fd_sectsize_info_t): fd_extern.h
        !            75:        contains ector size, 82077 sector size codem sects_per_track, gap.
        !            76:        One of these for each legal density/sectsize combo in ssi_Xmb[].
        !            77: 
        !            78: fd_density_info (fd_density_info_t) : fd_extern.h 
        !            79:        Maps density to capacity and mfm.
        !            80:        One per density in fdDensityInfo[].
        !            81:        
        !            82: fd_format_info (fd_format_info_t, fdFormatInfo_t) : fd_extern.h
        !            83:        Contains all current info about inserted disk. 
        !            84:        fd_disk_info, fd_density_info, fd_sectsize_info, total_sects, flags.
        !            85:        Obtained via ioctl(FDIOCGFORM).
        !            86:        
        !            87: fdDensitySectsize_t : FloppyTypes.h
        !            88:        maps density to an array of legal fd_sectsize_info's.
        !            89:        One per legal density in fdDensitySectsize[].
        !            90:        
        !            91: fdDriveInfo_t : FloppyPublic.h
        !            92:        drive_info (for ioctl(DKIOCGINFO)), seek, settle, unload time.
        !            93:        One per drive type (only one) in fdDriveInfo[].
        !            94:        

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