CONST
    vers           = 1.2;

    so             = 0;           { offset added to sector number }
    perscreen      = 20;          { pause long displays after lines }

    minsector      = 0;
    maxfatsize     = 1024;
    sectorsizemax  = 512;
    buffersize     = sectorsizemax;
    menumargin     = 18;
    clustersizemax = 2048;
    namesize       = 8;
    typesize       = 3;
    first          = true;
    next           = false;
    eodirectory    = $ff;
    mtdirectory    = 1;
    founddir       = 0;

    cr             = #$0d;      (* Ascii control chars *)
    eofmk          = #$1a;
    esc            = #$1b;
    dc3            = #$13;

  TYPE
    sizearray      = ARRAY[1..4] OF byte;
    str20          = string[20];
    bufr           = ARRAY[1..buffersize] OF char;
    cbufr          = ARRAY[1..clustersizemax] OF char;
    fatarray       = ARRAY[1..maxfatsize] OF byte;
    fat_id         = (unidentified, ss8spt, ds8spt,
                      ss9spt, ds9spt, b_20 );
    nameary        = ARRAY[1..namesize] OF char;
    typeary        = ARRAY[1..typesize] OF char;
    namestr        = string[20];
    anyfile        = FILE;        (* for generic file ops *)

    pc_fcb         = RECORD
      name           : nameary;
      extention      : typeary;
      attribute      : byte;
      rsrvd          : ARRAY[12..21] OF byte;
      time           : integer;
      date           : integer;
      clusterno      : integer;
      filesize       : sizearray;
      END;

    cpmfcb         = RECORD
      drivecode      : byte;
      name           : nameary;
      extention      : typeary;
      extent         : byte;
      s1, s2         : byte;
      rc             : byte;
      rsrvd          : ARRAY[16..31] OF byte;
      cr             : byte;
      r0, r1, r2     : byte;
      END;

  VAR
    cpm_buf        : ARRAY[1..128] OF char;
    done           : boolean;
    selection      : char;
    i              : integer;

    defaultdisk    : integer;
    ms_dos_drive   : integer;
    cpm_drive      : integer;
    cpm_drivech    : char;
    track          : integer;
    sector         : integer;

    secspercluster : integer;
    fat            : fatarray;
    fatsize        : integer;
    sectorsize     : integer;
    recordspersector : integer;
    dirsecs        : integer;
    ntracks        : integer;
    nsectors       : integer;
    nclusters      : integer;
    identity       : fat_id;

    firstfatsector : integer;
    firstdirsector : integer;
    firstdatasector : integer;
    firstdatatrack : integer;
    dirsector      : integer;
    dirtrack       : integer;
    dirsectorcount : integer;
    singlesided    : boolean;

    dos_fcb        : ^pc_fcb;
    cpm_fcb        : cpmfcb;
    buffer         : bufr;
    dirbuffer      : bufr;
    diroffset      : integer;
    dirname        : namestr;
    clusterbuffer  : cbufr;
    maxsector      : integer;
    outfile        : FILE;
    bioserror      : boolean;
    volumename     : boolean;
    subdirname     : boolean;