The $.$img files are sector$-$ordered raw $256$ byte block images of a DEC RX$02$

formatted floppy. $256$ bytes x $26$ sectors x $77$ tracks.

The disk was probably from a VAX running VMS$.$

CHM has no tools to decode these images to the file$-$level.

PLEASE WRITE A PYTHON SCRIPT TO HELP DECODE THESE $.$IMG FILES TO THE FILE LEVEL. BELOW IS A SCRIPT I MADE. PLEASE LET ME KNOW HOW I CAN FIX OR CHANGE IT:

import struct

import os

class ODS$1$Parser:

def $\_\_$init$\_\_($self$,$ image$\_$path$)$:

self.image$\_$path $=$ image$\_$path

self.block$\_$size $=256$ # Block size in bytes for RX$02$

def read$\_$block$($self$,$ file, block$\_$number$)$:

file.seek$($block$\_$number $*$ self.block$\_$size$)$

return file.read$($self$.$block$\_$size$)$

def find$\_$files$($self$,$ file, extension, start$\_$block$=37)$:

block$\_$number $=$ start$\_$block

file$\_$blocks $=\{\}$

while True:

block $=$ self.read$\_$block$($file$,$ block$\_$number$)$

if not block:

break

if extension.encode$()$ in block:

# Extract the filename and block number

start $=$ block.find$($extension$.$encode$())-9$

filename $=$ block$[$start:start$+12].$decode$(\text{'}$latin$1\text{'}).$strip$().$replace$(\text{'}\backslash$x$00\text{'},\text{'}\text{'})$

if filename.endswith$($extension$)$:

file$\_$blocks$[$filename$]=$ block$\_$number

block$\_$number $+=1$

return file$\_$blocks

def parse$\_$sector$($self$,$ block$)$:

# Parsing sector assuming the data starts at byte $33$ and ends at byte $289$

data $=$ block$[33$:$289]$

return data

def read$\_$file$($self$,$ file, start$\_$block$)$:

content $=$ b$""$

block$\_$number $=$ start$\_$block

while True:

block $=$ self.read$\_$block$($file$,$ block$\_$number$)$

if not block:

break

data $=$ self.parse$\_$sector$($block$)$

if b$\text{'}\backslash$x$00\text{'}*256==$ data:

break

content $+=$ data

block$\_$number $+=1$

return content

def format$\_$content$($self$,$ content$)$:

# This function attempts to format the content as LISP code

try:

return content.decode$(\text{'}$latin$1\text{'}).$replace$(\text{'}\backslash$xef$\backslash$xbf$\backslash$xbd$\text{'},\text{'}\text{'})$

except Exception as e:

return str$($e$)$

def parse$\_$filesystem$($self$)$:

with open$($self$.$image$\_$path, $\text{'}$rb$\text{'})$ as file:

lsp$\_$files $=$ self.find$\_$files$($file$,\text{'}.$LSP$\text{'},37)$

lsp$\_$contents $=\{\}$

for filename, start$\_$block in lsp$\_$files.items$()$:

content $=$ self.read$\_$file$($file$,$ start$\_$block$)$

formatted$\_$content $=$ self.format$\_$content$($content$)$

lsp$\_$contents$[$filename$]=$ formatted$\_$content

return lsp$\_$contents

def save$\_$files$($self$,$ lsp$\_$contents, output$\_$dir$)$:

os$.$makedirs$($output$\_$dir, exist$\_$ok$=$True$)$

for filename, content in lsp$\_$contents.items$()$:

output$\_$file$\_$path $=$ os$.$path.join$($output$\_$dir, filename$)$

with open$($output$\_$file$\_$path, $\text{'}$w$\text{'})$ as f:

f$.$write$($content$)$

print$("$Extracted: $\{\}".$format$($filename$))$

# Example usage

parser $=$ ODS$1$Parser$(\text{'}102719811\_$MYCIN$/$mycyn$1.$img'$)$

lsp$\_$contents $=$ parser.parse$\_$filesystem$()$

# Save the LSP files and their contents to the output directory

output$\_$dir $=$ 'extracted$\_$lsp$\_$files'

parser.save$\_$files$($lsp$\_$contents, output$\_$dir$)$

print$($f$"$Extracted files are saved in the $\text{'}\{$output$\_$dir$\}\text{'}$ directory."$)$