diff --git a/PO.pm b/PO.pm
new file mode 100644
index 0000000..f3aaf34
--- /dev/null
+++ b/PO.pm
@@ -0,0 +1,169 @@
+#!/usr/bin/perl -w
+
+package PO;
+
+#
+# PO.pm:
+#
+# Module for low level access to Apple II .PO disk images (ProDOS Order)
+#
+# 20190115 LSH
+#
+
+use strict;
+
+use Exporter::Auto;
+
+my $debug = 0;
+
+my $min_blk = 0;  # Minimum block number
+my $max_blk = 280;  # Maximum block number
+my $blk_size = 512;  # Block size
+
+#
+# Read entire .po image.
+#
+sub read_po {
+  my ($pofile) = @_;
+
+  my %po = ();
+
+  my $dfh;
+
+  if (open($dfh, "<$pofile")) {
+    for (my $blk = 0; $blk <= $max_blk; $blk++) {
+      my $bytes_read = read($dfh, $po{$blk}, $blk_size);
+      if (defined $bytes_read && $bytes_read == $blk_size) {
+        print '.';
+      } else {
+        print "\nError reading $blk\n";
+      }
+    }
+    print "\n";
+  } else {
+    print "Unable to open $pofile\n";
+  }
+
+  return %po;
+}
+
+#
+# Calculate position in .po file based on block.
+#
+sub calc_pos {
+  my ($blk) = @_;
+
+  my $pos = $blk * $blk_size;
+
+  #print "pos=$pos\n";
+
+  return $pos;
+}
+
+#
+# Hex dump of block
+#
+sub dump_blk {
+  my ($buf) = @_;
+
+  my @bytes = unpack "C$blk_size", $buf;
+
+  print "    ";
+  for (my $c = 0; $c < 16; $c++) {
+    print sprintf(" %1x ", $c);
+  }
+  print "\n";
+
+  print "  +------------------------------------------------\n";
+
+  for (my $r = 0; $r < 32; $r++) {
+    print sprintf("%02x| ", $r);
+    for (my $c = 0; $c < 16; $c++) {
+      print sprintf("%02x ", $bytes[($r * 16) + $c]);
+    }
+    print "\n";
+    print "  |";
+    for (my $c = 0; $c < 16; $c++) {
+      my $a = $bytes[($r * 16) + $c] & 0x7f;
+      if (($a > 32) && ($a < 127)) {
+        print sprintf(" %c ", $a);
+      } else {
+        print "   ";
+      }
+    }
+    print "\n";
+  }
+  print "\n";
+}
+
+#
+# Read block
+#
+sub read_blk {
+  my ($pofile, $blk, $buf) = @_;
+
+  #print "blk=$blk\n";
+
+  my $dfh;
+
+  my $pos = calc_pos($blk);
+
+  if (open($dfh, "<$pofile")) {
+    binmode $dfh;
+
+    seek($dfh, $pos, 0);
+
+    my $bytes_read = read($dfh, $$buf, $blk_size);
+
+    close $dfh;
+
+    if (defined $bytes_read && $bytes_read == $blk_size) {
+      #print "bytes_read=$bytes_read\n";
+      return 1;
+    } else {
+      print "Error reading $blk\n";
+    }
+  } else {
+    print "Unable to open $pofile\n";
+  }
+
+  return 0;
+}
+
+sub clear_buf {
+  my ($buf) = @_;
+
+  $$buf = pack "C*", 0x00 x 512;
+}
+
+#
+# Write Track/Sector
+#
+sub write_blk {
+  my ($pofile, $blk, $buf) = @_;
+
+  #print "blk=$blk\n";
+
+  my $dfh;
+
+  my $pos = calc_pos($blk);
+
+  if (open($dfh, "+<$pofile")) {
+    binmode $dfh;
+
+    seek($dfh, $pos, 0);
+
+    print $dfh $buf;
+
+    close $dfh;
+
+    return 1;
+  } else {
+    print "Unable to write $pofile\n";
+  }
+
+  return 0;
+}
+
+1;
+
diff --git a/ProDOS.pm b/ProDOS.pm
new file mode 100644
index 0000000..ff6f3a1
--- /dev/null
+++ b/ProDOS.pm
@@ -0,0 +1,1127 @@
+#!/usr/bin/perl -w
+
+package ProDOS;
+
+#
+# ProDOS.pm:
+#
+# Module to access Apple II ProDOS volumes.
+#
+# 20190115 LSH
+#
+
+use strict;
+
+use POSIX;
+
+use PO;
+
+use Exporter::Auto;
+
+my $debug = 0;
+
+# ProDOS file types
+my %ftype = (
+  # $0x Types: General
+
+  # 00        Typeless file
+  0x00 => '   ',
+  # 01    BAD Bad block(s) file
+  0x01 => 'BAD',
+  # 04    TXT Text file (ASCII text, msb off)
+  0x04 => 'TXT',
+  # 06    BIN Binary file (8-bit binary image)
+  0x06 => 'BIN',
+  # 07    FNT Apple /// Font
+  0x07 => 'FNT',
+  # 08    FOT HiRes/Double HiRes Graphics
+  0x08 => 'FOT',
+  # 09    BA3 Apple III BASIC Program
+  0x09 => 'BA3',
+  # 0A    DA3 Apple III BASIC Data
+  0x0a => 'DA3',
+  # 0B    WPF Generic Word Processing
+  0x0b => 'WPF',
+  # 0C    SOS SOS System File
+  0x0c => 'SOS',
+  # f    DIR Directory file
+  0x0f => 'DIR',
+
+  # $1x Types: Productivity
+
+  # 19    ADB AppleWorks data base file
+  0x19 => 'ADB',
+  # 1a    AWP AppleWorks word processing file
+  0x1a => 'AWP',
+  # 1b    ASP AppleWorks spreadsheet file
+  0x1b => 'ASP',
+
+  # $2x Types: Code
+
+  # $20 TDM Desktop Manager File
+  0x20 => 'TDM',
+  # $21 IPS Instant Pascal Source
+  0x21 => 'IPS',
+  # $22 UPV UCSD Pascal Volume
+  0x22 => 'UPV',
+  # $29 3SD SOS Directory
+  0x29 => '3SD',
+  # $2A 8SC Source Code
+  0x2a => '8SC',
+  # $2B 8OB Object Code
+  0x2b => '8OB',
+
+  # $2C 8IC Interpreted Code
+  0x2c => '8IC',
+  #     $8003 - Apex Program File
+
+  # $2D 8LD Language Data
+  0x2d => '8LD',
+  # $2E P8C ProDOS 8 Code Module
+  0x2e => 'P8C',
+
+  # $4x Types: Miscellaneous
+
+  # $41 OCR Optical Character Recognition
+  0x41 => 'OCR',
+  # $42 FTD File Type Definitions
+  0x42 => 'FTD',
+
+  # $5x Types: Apple IIgs General
+
+  # $50 GWP Apple IIgs Word Processing
+  0x50 => 'GWP',
+  #    $5445 - Teach
+  #    $8001 - DeluxeWrite
+  #    $8010 - AppleWorks GS
+
+  # $51 GSS Apple IIgs Spreadsheet
+  0x51 => 'GSS',
+  #    $8010 - AppleWorks GS
+
+  # $52 GDB Apple IIgs Database
+  0x52 => 'GDB',
+  #    $8010 - AppleWorks GS
+  #    $8011 - AppleWorks GS Template
+  #    $8013 - GSAS
+
+  # $53 DRW Object Oriented Graphics
+  0x53 => 'DRW',
+  #    $8010 - AppleWorks GS
+
+  # $54 GDP Apple IIgs Desktop Publishing
+  0x54 => 'GDP',
+  #    $8002 - GraphicWriter
+  #    $8010 - AppleWorks GS
+
+  # $55 HMD HyperMedia
+  0x55 => 'HMD',
+  #    $0001 - HyperCard GS
+  #    $8001 - Tutor-Tech
+  #    $8002 - HyperStudio
+  #    $8003 - Nexus
+
+  # $56 EDU Educational Program Data
+  0x56 => 'EDU',
+  # $57 STN Stationery
+  0x57 => 'STN',
+  # $58 HLP Help File
+  0x58 => 'HLP',
+
+  # $59 COM Communications
+  0x59 => 'COM',
+  #    $8010 - AppleWorks GS
+
+  # $5A CFG Configuration
+  0x5a => 'CFG',
+  # $5B ANM Animation
+  0x5b => 'ANM',
+  # $5C MUM Multimedia
+  0x5c => 'MUM',
+  # $5D ENT Entertainment
+  0x5d => 'ENT',
+  # $5E DVU Development Utility
+  0x5e => 'DVU',
+
+  # $6x Types: PC Transporter
+
+  # $60 PRE PC Pre-Boot
+  0x60 => 'PRE',
+  # $6B BIO PC BIOS
+  0x6b => 'BIO',
+  # $66 NCF ProDOS File Navigator Command File
+  0x66 => 'NCF',
+  # $6D DVR PC Driver
+  0x6d => 'DVR',
+  # $6E PRE PC Pre-Boot
+  0x6e => 'PRE',
+  # $6F HDV PC Hard Disk Image
+  0x6f => 'HDV',
+
+  # $7x Types: Kreative Software
+
+  # $70 SN2 Sabine's Notebook 2.0
+  0x70 => 'SN2',
+  # $71 KMT
+  0x71 => 'KMT',
+  # $72 DSR
+  0x72 => 'DSR',
+  # $73 BAN
+  0x73 => 'BAN',
+  # $74 CG7
+  0x74 => 'CG7',
+  # $75 TNJ
+  0x75 => 'TNJ',
+  # $76 SA7
+  0x76 => 'SA7',
+  # $77 KES
+  0x77 => 'KES',
+  # $78 JAP
+  0x78 => 'JAP',
+  # $79 CSL
+  0x79 => 'CSL',
+  # $7A TME
+  0x7a => 'TME',
+  # $7B TLB
+  0x7b => 'TLB',
+  # $7C MR7
+  0x7c => 'MR7',
+
+  # $7D MLR Mika City
+  0x7d => 'MLR',
+  #    $005C - Script
+  #    $C7AB - Color Table
+  #    $CDEF - Character Definition
+
+  # $7E MMM
+  0x7e => 'MMM',
+  # $7F JCP
+  0x7f => 'JCP',
+
+  # $8x Types: GEOS
+
+  # $80 GES System File
+  0x80 => 'GES',
+  # $81 GEA Desk Accessory
+  0x81 => 'GEA',
+  # $82 GEO Application
+  0x82 => 'GEO',
+  # $83 GED Document
+  0x83 => 'GED',
+  # $84 GEF Font
+  0x84 => 'GEF',
+  # $85 GEP Printer Driver
+  0x85 => 'GEP',
+  # $86 GEI Input Driver
+  0x86 => 'GEI',
+  # $87 GEX Auxiliary Driver
+  0x87 => 'GEX',
+  # $89 GEV Swap File
+  0x89 => 'GEV',
+  # $8B GEC Clock Driver
+  0x8b => 'GEC',
+  # $8C GEK Interface Card Driver
+  0x8c => 'GEK',
+  # $8D GEW Formatting Data
+  0x8d => 'GEW',
+
+  # $Ax Types: Apple IIgs BASIC
+
+  # $A0 WP  WordPerfect
+  0xa0 => 'WP ',
+  # $AB GSB Apple IIgs BASIC Program
+  0xab => 'GSB',
+  # $AC TDF Apple IIgs BASIC TDF
+  0xac => 'TDF',
+  # $AD BDF Apple IIgs BASIC Data
+  0xad => 'BDF',
+
+  # $Bx Types: Apple IIgs System
+
+  # $B0 SRC Apple IIgs Source Code
+  0xb0 => 'SRC',
+  # $B1 OBJ Apple IIgs Object Code
+  0xb1 => 'OBJ',
+  # $B2 LIB Apple IIgs Library
+  0xb2 => 'LIB',
+  # $B3 S16 Apple IIgs Application Program
+  0xb3 => 'S16',
+  # $B4 RTL Apple IIgs Runtime Library
+  0xb4 => 'RTL',
+  # $B5 EXE Apple IIgs Shell Script
+  0xb5 => 'EXE',
+  # $B6 PIF Apple IIgs Permanent INIT
+  0xb6 => 'PIF',
+  # $B7 TIF Apple IIgs Temporary INIT
+  0xb7 => 'TIF',
+  # $B8 NDA Apple IIgs New Desk Accessory
+  0xb8 => 'NDA',
+  # $B9 CDA Apple IIgs Classic Desk Accessory
+  0xb9 => 'CDA',
+  # $BA TOL Apple IIgs Tool
+  0xba => 'TOL',
+  # $BB DRV Apple IIgs Device Driver
+  0xbb => 'DRV',
+
+  # $BC LDF Apple IIgs Generic Load File
+  0xbc => 'LDF',
+  #    $4001 - Nifty List Module
+  #    $4002 - Super Info Module
+  #    $4004 - Twilight Module
+  #    $4083 - Marinetti Link Layer Module
+
+  # $BD FST Apple IIgs File System Translator
+  0xbd => 'FST',
+  # $BF DOC Apple IIgs Document
+  0xbf => 'DOC',
+
+  # $Cx Types: Graphics
+
+  # $C0 PNT Apple IIgs Packed Super HiRes
+  0xc0 => 'PNT',
+  #    $0001 - Packed Super HiRes
+  #    $0002 - Apple Preferred Format
+  #    $0003 - Packed QuickDraw II PICT
+
+  # $C1 PIC Apple IIgs Super HiRes
+  0xc1 => 'PIC',
+  #    $0001 - QuickDraw PICT
+  #    $0002 - Super HiRes 3200
+
+  # $C2 ANI PaintWorks Animation
+  0xc2 => 'ANI',
+  # $C3 PAL PaintWorks Palette
+  0xc3 => 'PAL',
+  # $C5 OOG Object-Oriented Graphics
+  0xc5 => 'OOG',
+  # $C6 SCR Script
+  0xc6 => 'SCR',
+  # $C7 CDV Apple IIgs Control Panel
+  0xc7 => 'CDV',
+
+  # $C8 FON Apple IIgs Font
+  0xc8 => 'FON',
+  #    $0000 - QuickDraw Bitmap Font
+  #    $0001 - Pointless TrueType Font
+
+  # $C9 FND Apple IIgs Finder Data
+  0xc9 => 'FND',
+  # $CA ICN Apple IIgs Icon File
+  0xca => 'ICN',
+
+  # $Dx Types: Audio
+
+  # $D5 MUS Music
+  0xd5 => 'MUS',
+  # $D6 INS Instrument
+  0xd6 => 'INS',
+  # $D7 MDI MIDI
+  0xd7 => 'MDI',
+
+  # $D8 SND Apple IIgs Audio
+  0xd8 => 'SND',
+  #    $0000 - AIFF
+  #    $0001 - AIFF-C
+  #    $0002 - ASIF Instrument
+  #    $0003 - Sound Resource
+  #    $0004 - MIDI Synth Wave
+  #    $8001 - HyperStudio Sound
+
+  # $DB DBM DB Master Document
+  0xdb => 'DBM',
+
+  # $Ex Types: Miscellaneous
+
+  # $E0 LBR Archive
+  0xe0 => 'LBR',
+  #    $0000 - ALU
+  #    $0001 - AppleSingle
+  #    $0002 - AppleDouble Header
+  #    $0003 - AppleDouble Data
+  #    $8000 - Binary II
+  #    $8001 - AppleLink ACU
+  #    $8002 - ShrinkIt
+
+  # $E2 ATK AppleTalk Data
+  0xe2 => 'ATK',
+  #    $FFFF - EasyMount Alias
+
+  # $EE R16 EDASM 816 Relocatable Code
+  0xee => 'R16',
+  # ef    PAS ProDOS PASCAL file
+  0xef => 'PAS',
+
+  # $Fx Types: System
+
+  # f0    CMD ProDOS added command file
+  0xf0 => 'CMD',
+  # f1-f8     User defined file types 1 through 8
+  0xf1 => 'OVL',
+  0xf2 => 'UD2',
+  0xf3 => 'UD3',
+  0xf4 => 'UD4',
+  0xf5 => 'BAT',
+  0xf6 => 'UD6',
+  0xf7 => 'UD7',
+  0xf8 => 'PRG',
+
+  # $F9 P16 ProDOS-16 System File
+  0xf9 => 'P16',
+
+  # fa    INT Integer BASIC Program
+  0xfa => 'INT',
+  # fb    IVR Integer BASIC Variables
+  0xfb => 'IVR',
+  # fc    BAS Applesoft BASIC program file
+  0xfc => 'BAS',
+  # fd    VAR Applesoft stored variables file
+  0xfd => 'VAR',
+  # fe    REL Relocatable object module file (EDASM)
+  0xfe => 'REL',
+  # ff    SYS ProDOS system file
+  0xff => 'SYS',
+);
+
+#
+# Months for catalog date format.
+#
+my %months = (
+   1, 'JAN',
+   2, 'FEB',
+   3, 'MAR',
+   4, 'APR',
+   5, 'MAY',
+   6, 'JUN',
+   7, 'JUL',
+   8, 'AUG',
+   9, 'SEP',
+  10, 'OCT',
+  11, 'NOV',
+  12, 'DEC',
+);
+
+# Default key volume directory block.
+my $key_vol_dir_blk = 2;
+
+#
+# Key Volume Directory Block
+#
+# 00-01 Previous Volume Directory Block
+# 02-03 Next Volume Directory Block
+#
+# Volumne Directory Header
+#
+# 04    STORAGE_TYPE/NAME_LENGTH
+#       fx where x is length of VOLUME_NAME
+# 05-13 VOLUME_NAME
+# 14-1b Not used
+# 1c-1f CREATION
+#       0-1 yyyyyyymmmmddddd  year/month/day
+#       2-3 000hhhhh00mmmmmm  hours/minues
+# 20    VERSION
+# 21    MIN_VERSION
+# 22    ACCESS
+# 23    ENTRY_LENGTH
+# 24    ENTRIES_PER_BLOCK
+# 25-26 FILE_COUNT
+# 27-28 BIT_MAP_POINTER
+# 29-2a TOTAL_BLOCKS
+#
+my $key_vol_dir_blk_tmpl = 'vvCa15x8vvCCCCCvvva470';
+
+my $vol_dir_blk_tmpl = 'vva504';
+
+#
+# Volume Bit Map
+#
+my $vol_bit_map_tmpl = 'C*';
+
+#
+# File Descriptive Entries
+#
+# 00    STORAGE_TYPE/NAME_LENGTH
+#       0x Deleted entry. Available for reuse.
+#       1x File is a seedling file (only one block)
+#       2x File is a sapling file (2-256 blocks)
+#       3x File is a tree file (257-32768 blocks)
+#       dx File is a subdirectory
+#       ex Reserved for Subdirectory Header entry
+#       fx Reserved for Volume Directory Header entry
+#          x is the length of FILE_NAME
+# 01-0f FILE_NAME
+# 10    FILE_TYPE
+#       00        Typeless file
+#       01    BAD Bad block(s) file
+#       04    TXT Text file (ASCII text, msb off)
+#       06    BIN Binary file (8-bit binary image)
+#       0f    DIR Directory file
+#       19    ADB AppleWorks data base file
+#       1a    AWP AppleWorks word processing file
+#       1b    ASP AppleWorks spreadsheet file
+#       ef    PAS ProDOS PASCAL file
+#       f0    CMD ProDOS added command file
+#       f1-f8     User defined file types 1 through 8
+#       fc    BAS Applesoft BASIC program file
+#       fd    VAR Applesoft stored variables file
+#       fe    REL Relocatable object module file (EDASM)
+#       ff    SYS ProDOS system file
+# 11-12 KEY_POINTER
+# 13-14 BLOCKS_USED
+# 15-17 EOF
+# 18-1b CREATION
+#       0-1 yyyyyyymmmmddddd  year/month/day
+#       2-3 000hhhhh00mmmmmm  hours/minues
+# 1c    VERSION
+# 1d    MIN_VERSION
+# 1e    ACCESS
+#       80 File may be destroyed
+#       40 File may be renamed
+#       20 File has changed since last backup
+#       02 File may be written to
+#       01 File may be read
+# 1f-20 AUX_TYPE
+#       TXT Random access record length (L from OPEN)
+#       BIN Load address for binary image (A from BSAVE)
+#       BAS Load address for program image (when SAVEd)
+#       VAR Address of compressed variables inmage (when STOREd)
+#       SYS Load address for system program (usually $2000)
+# 21-24 LAST_MOD
+# 25-26 HEADER_POINTER
+#
+my $file_desc_ent_tmpl = 'Ca15Cvva3vvCCCvvvv';
+
+my $key_dir_file_desc_ent_tmpl = '';
+my $subdir_hdr_file_desc_ent_tmpl = '';
+for (my $i = 0; $i < 12; $i++) {
+  $key_dir_file_desc_ent_tmpl .= $file_desc_ent_tmpl;
+  $subdir_hdr_file_desc_ent_tmpl .= $file_desc_ent_tmpl;
+}
+
+my $dir_file_desc_ent_tmpl = '';
+my $subdir_file_desc_ent_tmpl = '';
+for (my $i = 0; $i < 12; $i++) {
+  $dir_file_desc_ent_tmpl .= $file_desc_ent_tmpl;
+  $subdir_file_desc_ent_tmpl .= $file_desc_ent_tmpl;
+}
+
+#
+# Subdirectory Header
+#
+# 00-01 Previous Subdirectory Block
+# 02-03 Next Subdirectory Block
+#
+# 04    STORAGE_TYPE/NAME_LENGTH
+#       ex where x is length of SUBDIR NAME
+#
+# 05-13 SUBDIR_NAME
+# 14    Must contain $75
+# 15-1b Reserved for future use
+# 1c-1f CREATION
+#       0-1 yyyyyyymmmmddddd  year/month/day
+#       2-3 000hhhhh00mmmmmm  hours/minues
+# 20    VERSION
+# 21    MIN_VERSION
+# 22    ACCESS
+# 23    ENTRY_LENGTH
+# 24    ENTRIES_PER_BLOCK
+# 25-26 FILE_COUNT
+# 27-28 PARENT_POINTER
+# 29    PARENT_ENTRY
+# 2a    PARENT_ENTRY_LENGTH
+#
+my $subdir_hdr_blk_tmpl = 'vvCa15Cx7vvCCCCCvvCCa469';
+
+
+#
+# Convert a ProDOS date to DD-MMM-YY string.
+#
+sub date_convert {
+  my ($ymd, $hm) = @_;
+
+  return "<NO DATE>" unless (defined $ymd && defined $hm && $ymd != 0);
+
+  my $year = ($ymd & 0xfe00) >> 9;  # bits 9-15
+  my $mon = ($ymd & 0x01e0) >> 5;  # bits 5-8
+  my $day = $ymd & 0x001f;  # bits 0-4
+  my $hour = ($hm & 0x1f00) >> 8;  # bits 8-12
+  my $min = $hm & 0x003f;  # bits 0-5
+  $mon = 0 if $mon > 12;
+
+  return "<NO DATE>" if $mon < 1;
+
+  return sprintf("%2d-%s-%02d %2d:%02d", $day, $months{$mon}, $year, $hour, $min);
+}
+
+# Parse Key Volume Directory Block
+sub parse_key_vol_dir_blk {
+  my ($buf, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $volume_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $bit_map_pointer, $total_blocks, $dir_ents) = unpack $key_vol_dir_blk_tmpl, $buf;
+
+  my $storage_type = ($storage_type_name_length & 0xf0) >> 4;
+  my $name_length = $storage_type_name_length & 0x0f;
+
+  my $volname = substr($volume_name, 0, $name_length);
+
+  my @flds = unpack $key_dir_file_desc_ent_tmpl, $dir_ents;
+
+  my @files = ();
+  for (my $i = 0; $i < 12; $i++) {
+    my $storage_type_name_length = shift @flds;
+    my $storage_type = ($storage_type_name_length & 0xf0) >> 4;
+    my $name_length = $storage_type_name_length & 0x0f;
+    my $file_name = shift @flds;
+    my $fname = substr($file_name, 0, $name_length);
+    my $file_type = shift @flds;
+    my $key_pointer = shift @flds;
+    my $blocks_used = shift @flds;
+    my $eof = shift @flds;
+    my ($e1, $e2, $e3)  = unpack "C*", $eof;
+    my $endfile = (($e3 << 16) + ($e2 << 8) + $e1);
+    my $creation_ymd = shift @flds;
+    my $creation_hm = shift @flds;
+    my $cdate = date_convert($creation_ymd, $creation_hm);
+    my $version = shift @flds;
+    my $min_version = shift @flds;
+    my $access = shift @flds;
+    my $aux_type = shift @flds;
+    my $atype = '';
+    if ($file_type == 0x06) {
+      $atype = sprintf("A=\$%04X", $aux_type);
+    }
+    my $last_mod_ymd = shift @flds;
+    my $last_mod_hm = shift @flds;
+    my $mdate = date_convert($last_mod_ymd, $last_mod_hm);
+    my $header_pointer = shift @flds;
+    if ($storage_type != 0) {
+      my $f_type = $ftype{$file_type};
+      $f_type = sprintf("\$%02x", $file_type) unless defined $f_type;
+      push @files, { 'filename' => $fname, 'ftype' => $f_type, 'used' => $blocks_used, 'mdate' => $mdate, 'cdate' => $cdate, 'atype' => $aux_type, 'atype' => $atype, 'access' => $access, 'eof' => $endfile, 'keyptr' => $key_pointer, 'storage_type' => $storage_type };
+    }
+  }
+
+  return $prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $volname, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $bit_map_pointer, $total_blocks, @files;
+}
+
+#
+# Get Key Volume Directory Block
+#
+sub get_key_vol_dir_blk {
+  my ($pofile, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my $buf;
+
+  if (read_blk($pofile, $key_vol_dir_blk, \$buf)) {
+    dump_blk($buf) if $debug;
+    return parse_key_vol_dir_blk($buf, $debug);
+  }
+
+  return 0;
+}
+
+# Parse Volume Directory Block
+sub parse_vol_dir_blk {
+  my ($buf, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $dir_ents) = unpack $vol_dir_blk_tmpl, $buf;
+
+  my @flds = unpack $dir_file_desc_ent_tmpl, $dir_ents;
+
+  my @files = ();
+  for (my $i = 0; $i < 12; $i++) {
+    my $storage_type_name_length = shift @flds;
+    my $storage_type = ($storage_type_name_length & 0xf0) >> 4;
+    my $name_length = $storage_type_name_length & 0x0f;
+    my $file_name = shift @flds;
+    my $fname = substr($file_name, 0, $name_length);
+    my $file_type = shift @flds;
+    my $key_pointer = shift @flds;
+    my $blocks_used = shift @flds;
+    my $eof = shift @flds;
+    my ($e1, $e2, $e3)  = unpack "C*", $eof;
+    my $endfile = (($e3 << 16) + ($e2 << 8) + $e1);
+    my $creation_ymd = shift @flds;
+    my $creation_hm = shift @flds;
+    my $cdate = date_convert($creation_ymd, $creation_hm);
+    my $version = shift @flds;
+    my $min_version = shift @flds;
+    my $access = shift @flds;
+    my $aux_type = shift @flds;
+    my $atype = '';
+    if ($file_type == 0x06) {
+      $atype = sprintf("A=\$%04X", $aux_type);
+    }
+    my $last_mod_ymd = shift @flds;
+    my $last_mod_hm = shift @flds;
+    my $mdate = date_convert($last_mod_ymd, $last_mod_hm);
+    my $header_pointer = shift @flds;
+    if ($storage_type != 0) {
+      my $f_type = $ftype{$file_type};
+      $f_type = sprintf("\$%02x", $file_type) unless defined $f_type;
+      push @files, { 'filename' => $fname, 'ftype' => $f_type, 'used' => $blocks_used, 'mdate' => $mdate, 'cdate' => $cdate, 'atype' => $aux_type, 'atype' => $atype, 'access' => $access, 'eof' => $endfile, 'keyptr' => $key_pointer, 'storage_type' => $storage_type };
+    }
+  }
+
+  return $prv_vol_dir_blk, $nxt_vol_dir_blk, @files;
+}
+
+#
+# Get Volume Directory Block
+#
+sub get_vol_dir_blk {
+  my ($pofile, $vol_dir_blk, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my $buf;
+
+  if (read_blk($pofile, $vol_dir_blk, \$buf)) {
+    dump_blk($buf) if $debug;
+    return parse_vol_dir_blk($buf, $debug);
+  }
+
+  return 0;
+}
+
+# Parse Key Volume Directory Block
+sub parse_subdir_hdr_blk {
+  my ($buf, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $subdir_name, $foo, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $parent_pointer, $parent_entry, $parent_entry_length, $dir_ents) = unpack $subdir_hdr_blk_tmpl, $buf;
+
+  my $storage_type = ($storage_type_name_length & 0xf0) >> 4;
+  my $name_length = $storage_type_name_length & 0x0f;
+
+  my $subdir_nm = substr($subdir_name, 0, $name_length);
+
+  my @flds = unpack $subdir_hdr_file_desc_ent_tmpl, $dir_ents;
+
+  my @files = ();
+  for (my $i = 0; $i < 12; $i++) {
+    my $storage_type_name_length = shift @flds;
+    my $storage_type = ($storage_type_name_length & 0xf0) >> 4;
+    print sprintf("storage_type_name_length=%02x\n", $storage_type_name_length);
+    print sprintf("storage_type=%02x\n", $storage_type);
+    my $name_length = $storage_type_name_length & 0x0f;
+    print sprintf("name_length=%02x\n", $name_length) if $debug;
+    my $file_name = shift @flds;
+    my $fname = substr($file_name, 0, $name_length);
+    print sprintf("fname=%s\n", $fname) if $debug;
+    my $file_type = shift @flds;
+    print sprintf("file_type=%02x\n", $file_type) if $debug;
+    my $key_pointer = shift @flds;
+    my $blocks_used = shift @flds;
+    my $eof = shift @flds;
+    my ($e1, $e2, $e3)  = unpack "C*", $eof;
+    my $endfile = (($e3 << 16) + ($e2 << 8) + $e1);
+    my $creation_ymd = shift @flds;
+    my $creation_hm = shift @flds;
+    my $cdate = date_convert($creation_ymd, $creation_hm);
+    my $version = shift @flds;
+    my $min_version = shift @flds;
+    my $access = shift @flds;
+    my $aux_type = shift @flds;
+    my $atype = '';
+    if ($file_type == 0x06) {
+      $atype = sprintf("A=\$%04X", $aux_type);
+    }
+    my $last_mod_ymd = shift @flds;
+    my $last_mod_hm = shift @flds;
+    my $mdate = date_convert($last_mod_ymd, $last_mod_hm);
+    my $header_pointer = shift @flds;
+    if ($storage_type != 0) {
+      my $f_type = $ftype{$file_type};
+      $f_type = sprintf("\$%02x", $file_type) unless defined $f_type;
+      push @files, { 'filename' => $fname, 'ftype' => $f_type, 'used' => $blocks_used, 'mdate' => $mdate, 'cdate' => $cdate, 'atype' => $aux_type, 'atype' => $atype, 'access' => $access, 'eof' => $endfile, 'keyptr' => $key_pointer, 'storage_type' => $storage_type };
+    }
+  }
+
+  return $prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $subdir_nm, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $parent_pointer, $parent_entry, $parent_entry_length, @files;
+}
+
+sub get_subdir_hdr {
+  my ($pofile, $subdir_blk, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my $buf;
+
+  if (read_blk($pofile, $subdir_blk, \$buf)) {
+    dump_blk($buf) if $debug;
+    return parse_subdir_hdr_blk($buf, $debug);
+  }
+
+  return 0;
+}
+
+sub list_files {
+  my ($pofile, $pre, $dirname, $files) = @_;
+
+  print "$pre/$dirname\n";
+
+  foreach my $file (@{$files}) {
+    my $lck = ' ';
+    if ($file->{'access'} == 0x01) {
+      $lck = '*';
+    }
+    print sprintf("$pre%s%-15s %3s %7d %16s %16s  %7s %s\n", $lck, $file->{'filename'}, $file->{'ftype'}, $file->{'used'}, $file->{'mdate'}, $file->{'cdate'}, $file->{'eof'}, $file->{'atype'});
+
+    if ($file->{'ftype'} eq 'DIR') {
+      my $subdir_blk = $file->{'keyptr'};
+
+      my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $subdir_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $parent_pointer, $parent_entry, $parent_entry_length, @subfiles) = get_subdir_hdr($pofile, $subdir_blk, $debug);
+
+      list_files($pofile, '  ' . $pre, $subdir_name, \@subfiles);
+    }
+  }
+}
+
+#
+# Get disk catalog.
+#
+sub cat {
+  my ($pofile, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $volume_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $bit_map_pointer, $total_blocks, @files) = get_key_vol_dir_blk($pofile, $debug);
+
+  print "/$volume_name\n\n";
+
+  print " NAME           TYPE  BLOCKS  MODIFIED         CREATED          ENDFILE SUBTYPE\n\n";
+
+  foreach my $file (@files) {
+    my $lck = ' ';
+    if ($file->{'access'} == 0x01) {
+      $lck = '*';
+    }
+    print sprintf("%s%-15s %3s %7d %16s %16s  %7s %s\n", $lck, $file->{'filename'}, $file->{'ftype'}, $file->{'used'}, $file->{'mdate'}, $file->{'cdate'}, $file->{'eof'}, $file->{'atype'});
+
+    if ($file->{'ftype'} eq 'DIR') {
+      my $subdir_blk = $file->{'keyptr'};
+
+      my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $subdir_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $parent_pointer, $parent_entry, $parent_entry_length, @subfiles) = get_subdir_hdr($pofile, $subdir_blk, $debug);
+      my $pre = '  ';
+      list_files($pofile, '  ' . $pre, $subdir_name, \@subfiles);
+    }
+  }
+
+  my $vol_dir_blk = $nxt_vol_dir_blk;
+
+  while ($vol_dir_blk) {
+    my ($prv_vol_dir_blk, $nxt_vol_dir_blk, @files) = get_vol_dir_blk($pofile, $vol_dir_blk, $debug);
+    foreach my $file (@files) {
+      my $lck = ' ';
+      if ($file->{'access'} == 0x01) {
+        $lck = '*';
+      }
+      print sprintf("%s%-15s %3s %7d %16s %16s  %7s %s\n", $lck, $file->{'filename'}, $file->{'ftype'}, $file->{'used'}, $file->{'mdate'}, $file->{'cdate'}, $file->{'eof'}, $file->{'atype'});
+
+      if ($file->{'ftype'} eq 'DIR') {
+        my $subdir_blk = $file->{'keyptr'};
+
+        my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $subdir_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $parent_pointer, $parent_entry, $parent_entry_length, @subfiles) = get_subdir_hdr($pofile, $subdir_blk, $debug);
+
+        my $pre = '  ';
+        list_files($pofile, '  ' . $pre, $subdir_name, \@subfiles);
+      }
+    }
+    $vol_dir_blk = $nxt_vol_dir_blk;
+  }
+}
+
+# Parse master index block (tree file)
+sub parse_master_ind_blk {
+  my ($buf, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+}
+
+# Get master index block (tree file)
+sub get_master_ind_blk {
+  my ($pofile, $master_ind_blk, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  #print "pofile=$pofile master_ind_blk=$master_ind_blk\n";
+
+  my $buf;
+
+  my @blocks = ();
+
+  if (read_blk($pofile, $master_ind_blk, \$buf)) {
+    dump_blk($buf) if $debug;
+  }
+
+  return @blocks;
+}
+
+# Parse index block (sapling file)
+sub parse_ind_blk {
+  my ($buf, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+}
+
+# Get index block (sapling file)
+sub get_ind_blk {
+  my ($pofile, $ind_blk, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  #print "pofile=$pofile ind_blk=$ind_blk\n";
+
+  my $buf;
+
+  my @blocks = ();
+
+  if (read_blk($pofile, $ind_blk, \$buf)) {
+    dump_blk($buf) if $debug;
+    my (@lo) = unpack "C256", $buf;
+    #foreach my $byte (@lo) {
+    #  print sprintf("%02x ", $byte);
+    #}
+    #print "\n";
+    my (@hi) = unpack "x256C256", $buf;
+    #foreach my $byte (@hi) {
+    #  print sprintf("%02x ", $byte);
+    #}
+    #print "\n";
+    for (my $b = 0; $b < 256; $b++) {
+      #print sprintf("lo=%02x hi=%02x\n", $lo[$b], $hi[$b]);
+      my $blk = ($hi[$b] << 8) | $lo[$b];
+      #print sprintf("blk=%04x\n", $blk);
+      push @blocks, $blk;
+    }
+  }
+
+  return @blocks;
+}
+
+#
+# Find a file
+#
+sub find_file {
+  my ($pofile, $filename, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  #print "pofile=$pofile filename=$filename\n";
+
+  my $storage_type = 0;
+  my $file_type = 0x00;
+  my $key_pointer = 0x00;
+  my $blocks_used = 0x00;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $volume_name, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $bit_map_pointer, $total_blocks, @files) = get_key_vol_dir_blk($pofile, $debug);
+
+  my $found_it = 0;
+  foreach my $file (@files) {
+    #print "file=$file->{'filename'}\n";
+    if ($file->{'filename'} eq $filename) {
+      #print "FOUND IT!\n";
+      $found_it = 1;
+      $storage_type = $file->{'storage_type'};
+      $file_type = $file->{'ftype'};
+      $key_pointer = $file->{'keyptr'};
+      $blocks_used = $file->{'used'};
+      last;
+    }
+  }
+
+  if (! $found_it) {
+    my $vol_dir_blk = $nxt_vol_dir_blk;
+
+    while ($vol_dir_blk) {
+      my ($prv_vol_dir_blk, $nxt_vol_dir_blk, @files) = get_vol_dir_blk($pofile, $vol_dir_blk, $debug);
+
+      foreach my $file (@files) {
+        #print "file=$file->{'filename'}\n";
+        if ($file->{'filename'} eq $filename) {
+          #print "FOUND IT!\n";
+          $found_it = 1;
+          $storage_type = $file->{'storage_type'};
+          $file_type = $file->{'ftype'};
+          $key_pointer = $file->{'keyptr'};
+          $blocks_used = $file->{'used'};
+          last;
+        }
+      }
+      $vol_dir_blk = $nxt_vol_dir_blk;
+      last if $found_it;
+    }
+  }
+
+  print "File not found\n" unless $found_it;
+
+  return $storage_type, $file_type, $key_pointer, $blocks_used;
+}
+
+#
+# Read a file
+#
+sub read_file {
+  my ($pofile, $filename, $mode, $conv, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  print "pofile=$pofile filename=$filename mode=$mode conv=$conv\n" if $debug;
+
+  my ($storage_type, $file_type, $key_pointer, $blocks_used) = find_file($pofile, $filename, $debug);
+
+  return if $storage_type == 0;
+
+  my $buf;
+
+  print "storage_type=$storage_type file_type=$file_type key_pointer=$key_pointer blocks_used=$blocks_used\n" if $debug;
+
+  # Seedling file, only 1 block
+  if ($storage_type == 1) {
+    my $buf2;
+
+    if (read_blk($pofile, $key_pointer, \$buf2)) {
+      #dump_blk($buf) if $debug;
+      dump_blk($buf);
+      my @bytes = unpack "C*", $buf2;
+      foreach my $byte (@bytes) {
+        # For text file translation.
+        last if $byte == 0x00 && $mode eq 'T';
+        # Translate \r to \n
+        $byte = 0x0a if $byte == 0x8d && $conv;
+        # Convert Apple II ASCII to standard ASCII (clear high bit)
+        $byte &= 0x7f if $mode eq 'T';
+        #print sprintf("%c", $byte & 0x7f);
+        print sprintf("%c", $byte);
+      }
+    }
+  # Sapling file, 2-256 blocks
+  } elsif ($storage_type == 2) {
+    my @blks = get_ind_blk($pofile, $key_pointer, $debug);
+
+    my $buf2;
+
+    my $blkno = 1;
+    foreach my $blk (@blks) {
+      #print "blkno=$blkno blk=$blk\n";
+      clear_buf(\$buf2);
+      if (read_blk($pofile, $blk, \$buf2)) {
+        dump_blk($buf2) if $debug;
+        my @bytes = unpack "C*", $buf2;
+        foreach my $byte (@bytes) {
+          # For text file translation.
+          last if $byte == 0x00 && $mode eq 'T';
+          # Translate \r to \n
+          $byte = 0x0a if $byte == 0x8d && $conv;
+          # Convert Apple II ASCII to standard ASCII (clear high bit)
+          $byte &= 0x7f if $mode eq 'T';
+          #print sprintf("%c", $byte & 0x7f);
+          print sprintf("%c", $byte);
+        }
+      }
+      last if $blkno++ == $blocks_used - 1;
+    }
+  # Tree file, 257+ blocks
+  } elsif ($storage_type == 3) {
+    my @blks = get_master_ind_blk($pofile, $key_pointer, $debug);
+    ##FIXME -- need to handle Tree files here.
+  } else {
+    print "Not a regular file!\n";
+  }
+}
+
+#
+# Parse volume bit map
+#
+sub parse_vol_bit_map {
+  my ($buf, $dbg) = @_;
+
+  my @blocks = ();
+
+  my (@bytes) = unpack $vol_bit_map_tmpl, $buf;
+
+  foreach my $byte (@bytes) {
+    #print sprintf("%02x ", $byte);
+    #print sprintf("%08b ", $byte);
+    push @blocks, $byte;
+  }
+  print "\n";
+
+  return @blocks;
+}
+
+#
+# Get volume bit map
+#
+sub get_vol_bit_map {
+  my ($pofile, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my ($prv_vol_dir_blk, $nxt_vol_dir_blk, $storage_type_name_length, $volname, $creation_ymd, $creation_hm, $version, $min_version, $access, $entry_length, $entries_per_block, $file_count, $bit_map_pointer, $total_blocks, @files) = get_key_vol_dir_blk($pofile, $debug);
+
+  my $buf;
+
+  #print sprintf("bit_map_pointer=%04x\n", $bit_map_pointer) if $debug;
+
+  # Need to use total_blocks to calculate the number of volume bit map blocks.
+  #print sprintf("total_blocks=%04x\n", $total_blocks);
+  my $num_tracks = $total_blocks / 8;
+  #print sprintf("num_tracks=%d\n", $num_tracks);
+  my $num_vol_bit_map_blks = ceil($num_tracks / 512.0);
+  #print sprintf("num_vol_bit_map_blks=%d\n", $num_vol_bit_map_blks);
+  $num_vol_bit_map_blks = 1 if $num_vol_bit_map_blks < 1;
+  #print sprintf("num_vol_bit_map_blks=%d\n", $num_vol_bit_map_blks);
+
+  my @blocks = ();
+
+  my $trk = 0;
+  for (my $blk = $bit_map_pointer; $blk < $bit_map_pointer + $num_vol_bit_map_blks; $blk++) {
+    clear_buf(\$buf);
+    if (read_blk($pofile, $bit_map_pointer, \$buf)) {
+      dump_blk($buf) if $debug;
+      my (@blks) = parse_vol_bit_map($buf, $debug);
+      foreach my $blk (@blks) {
+        #print sprintf("%02x ", $blk);
+        push @blocks, $blk;
+        last if $trk++ >= $num_tracks;
+      }
+      #print "\n";
+    }
+  }
+
+  return @blocks;
+}
+
+#
+# Display blocks free map
+#
+sub freemap {
+  my ($pofile, $dbg) = @_;
+
+  $debug = 1 if defined $dbg && $dbg;
+
+  my (@blocks) = get_vol_bit_map($pofile, $debug);
+
+  print "    12345678\n";
+  print "   +--------\n";
+
+  my $trk = 0;
+  foreach my $byte (@blocks) {
+    my $bits = sprintf("%08b", $byte);
+    $bits =~ s/[0]/ /g;
+    $bits =~ s/[1]/\*/g;
+    print sprintf("%2d |%s\n", $trk++, $bits);
+  }
+  print "\n";
+}
+
+1;
+
diff --git a/README b/README
new file mode 100644
index 0000000..2f452cc
--- /dev/null
+++ b/README
@@ -0,0 +1,11 @@
+TODO:
+
+prozap.pl -- partially working
+procat.pl -- partially working
+profree.pl -- partially working
+proread.pl -- partially working
+prowrite.pl
+prorename.pl
+prodelete.pl
+procopy.pl
+
diff --git a/procat.pl b/procat.pl
new file mode 100644
index 0000000..f5bb72c
--- /dev/null
+++ b/procat.pl
@@ -0,0 +1,37 @@
+#!/usr/bin/perl -w
+
+#
+# procat.pl:
+#
+# Utility to get a 'catalog' (directory listing) of an Apple II ProDOS volume.
+#
+# 20190115 LSH
+#
+
+use strict;
+
+use ProDOS;
+
+my $debug = 0;
+
+my $blk = 0x0;
+
+while (defined $ARGV[0] && $ARGV[0] =~ /^-/) {
+  if ($ARGV[0] eq '-d') {
+    $debug = 1;
+    shift;
+  } elsif ($ARGV[0] eq '-b' && defined $ARGV[1] && $ARGV[1] =~ /^\d+$/) {
+    $blk = $ARGV[1];
+    shift;
+    shift;
+  } else {
+    die "Unknown command line argument $ARGV[0]\n";
+  }
+}
+
+my $pofile = shift or die "Must supply .po filename\n";
+
+cat($pofile, $debug);
+
+1;
+
diff --git a/profree.pl b/profree.pl
new file mode 100644
index 0000000..f862799
--- /dev/null
+++ b/profree.pl
@@ -0,0 +1,31 @@
+#!/usr/bin/perl -w
+
+#
+# profree.pl:
+#
+# Utility to get a free sector map of an Apple II ProDOS volume.
+#
+# 20190116 LSH
+#
+
+use strict;
+
+use ProDOS;
+
+my $debug = 0;
+
+while (defined $ARGV[0] && $ARGV[0] =~ /^-/) {
+  if ($ARGV[0] eq '-d') {
+    $debug = 1;
+    shift;
+  } else {
+    die "Unknown command line argument $ARGV[0]\n";
+  }
+}
+
+my $pofile = shift or die "Must supply .po filename\n";
+
+freemap($pofile, $debug);
+
+1;
+
diff --git a/proread.pl b/proread.pl
new file mode 100644
index 0000000..28dba1c
--- /dev/null
+++ b/proread.pl
@@ -0,0 +1,66 @@
+#!/usr/bin/perl -w
+
+#
+# proread.pl:
+#
+# Utility to read a file out of an Apple II ProDOS .po disk image.
+#
+# 20190116 LSH
+#
+
+use strict;
+
+use ProDOS;
+
+my $mode = 'T';  # T=Text
+my $conv = 1;  # Convert \r to \n
+my $debug = 0;
+
+while (defined $ARGV[0] && $ARGV[0] =~ /^-/) {
+  # Mode
+  if ($ARGV[0] eq '-m' && defined $ARGV[1] && $ARGV[1] ne '') {
+    # Text
+    if ($ARGV[1] eq 'T') {
+      $mode = 'T';
+      $conv = 1;
+    # Integer BASIC
+    } elsif ($ARGV[1] eq 'I') {
+      $mode = 'I';
+      $conv = 0;
+    # Applesoft
+    } elsif ($ARGV[1] eq 'A') {
+      $mode = 'A';
+      $conv = 0;
+    # Binary
+    } elsif ($ARGV[1] eq 'B') {
+      $mode = 'B';
+      $conv = 0;
+    # S
+    } elsif ($ARGV[1] eq 'S') {
+      $mode = 'S';
+      $conv = 0;
+    } else {
+      die "Unknown mode for -m, must be T, I, A, B or S\n";
+    }
+    shift;
+    shift;
+  # Convert (carriage return to linefeed)
+  } elsif ($ARGV[0] eq '-c') {
+    $conv = 0;
+    shift;
+  # Debug
+  } elsif ($ARGV[0] eq '-d') {
+    $debug = 1;
+    shift;
+  } else {
+    die "Unknown command line argument $ARGV[0]\n";
+  }
+}
+
+my $pofile = shift or die "Must supply .po filename\n";
+my $filename = shift or die "Must supply filename (on disk image)\n";
+
+read_file($pofile, $filename, $mode, $conv, $debug);
+
+1;
+
diff --git a/prozap.pl b/prozap.pl
new file mode 100644
index 0000000..643d1f1
--- /dev/null
+++ b/prozap.pl
@@ -0,0 +1,119 @@
+#!/usr/bin/perl -w
+
+#
+# prozap.pl:
+#
+# Utility to edit a ProDOS block (.PO image).
+#
+# 20190115 LSH
+#
+
+use strict;
+
+use PO;
+
+my $debug = 0;
+
+my $blk = -1;
+my $dst_blk = -1;
+my $write = 0;
+
+my @mods = ();
+
+while (defined $ARGV[0] && $ARGV[0] =~ /^-/) {
+  # Debug
+  if ($ARGV[0] eq '-d') {
+    $debug = 1;
+    shift;
+  # Block to read
+  } elsif ($ARGV[0] eq '-b' && defined $ARGV[1] && $ARGV[1] =~ /^\d+$/) {
+    $blk = $ARGV[1];
+    shift;
+    shift;
+  # Destination block
+  } elsif ($ARGV[0] eq '-db' && defined $ARGV[1] && $ARGV[1] =~ /^\d+$/) {
+    $dst_blk = $ARGV[1];
+    shift;
+    shift;
+  # Allow modifying data.
+  } elsif ($ARGV[0] =~ /^-m([ahA])/ && defined $ARGV[1] && $ARGV[1] ne '') {
+    my $typ = $1;
+    print "$ARGV[1] typ=$typ\n" if $debug;
+    if ($ARGV[1] =~ /^([0-9a-fA-F]+):\s*(.+)$/) {
+      print "1=$1 2=$2\n" if $debug;
+      push @mods, { 'typ' => $typ, 'addr' => $1, 'vals' => $2 };
+    }
+    shift;
+    shift;
+  } elsif ($ARGV[0] eq "-w") {
+    $write = 1;
+    shift;
+  } else {
+    die "Unknown command line argument $ARGV[0]\n";
+  }
+}
+
+my $pofile = shift or die "Must supply .po filename\n";
+die "Must supply block number 0-280\n" unless $blk >= 0 && $blk <= 280;
+
+$dst_blk = $blk unless $dst_blk >= 0;
+
+my $buf;
+
+# Read the block
+if (read_blk($pofile, $blk, \$buf)) {
+  # Display the data in the block.
+  dump_blk($buf);
+
+  # Allow modifying the data.
+  if ($write) {
+    print "WRITING $dst_blk\n" if $debug;
+    # Unpack the data in the block
+    my @bytes = unpack "C512", $buf;
+
+    # Process each modification.
+    foreach my $mod (@mods) {
+      my @mbytes = ();
+      if ($mod->{'typ'} eq 'a') {
+        print "ASCII vals=$mod->{'vals'}\n" if $debug;
+        # Normal ASCII
+        @mbytes = map { pack('C', ord($_)) } ($mod->{'vals'} =~ /(.)/g);
+      } elsif ($mod->{'typ'} eq 'A') {
+        print "HEX vals=$mod->{'vals'}\n" if $debug;
+        # Apple II ASCII
+        @mbytes = map { pack('C', ord($_) | 0x80) } ($mod->{'vals'} =~ /(.)/g);
+      } elsif ($mod->{'typ'} eq 'h') {
+        print "A2 ASCII vals=$mod->{'vals'}\n" if $debug;
+        # HEX
+        @mbytes = map { pack('C', hex(lc($_))) } ($mod->{'vals'} =~ /(..)/g);
+      }
+      my $addr = hex($mod->{'addr'});
+      print "addr=$addr\n" if $debug;
+      foreach my $byte (@mbytes) {
+        print sprintf("byte=%02x\n", ord($byte)) if $debug;
+        $bytes[$addr++] = ord($byte);
+      }
+    }
+
+    # Re-pack the data in the block
+    $buf = pack "C*", @bytes;
+
+    # Write the destination block (default to block read).
+    if (write_blk($pofile, $dst_blk, $buf)) {
+      # Read the block back in.
+      if (read_blk($pofile, $dst_blk, \$buf)) {
+        # Display the data in the modified block.
+        dump_blk($buf);
+      } else {
+        print "Failed final read!\n";
+      }
+    } else {
+      print "Failed write!\n";
+    }
+  }
+} else {
+  print "Failed initial read!\n";
+}
+
+1;
+