mirage-disk

#!/bin/bash

# mirage-disk - jzu@free.fr 2001-2013 - WTFPL
# Dumps sound data from a Mirage-formatted diskette
# Creates a directory located in $HOME/mirage and, first, splits the 
# contents of the diskette in small files, two per track (the second 
# containing the last sector of the track, basically meta-data)
# The first file is named dXX.dmp (data from track XX)
# The second one is named sXX.dmp (small sector from track XX)
# These track files are then concatenated in sample files.

# Ensoniq Mirage diskettes are formatted this (quite weird) way:
# single-sided
# 80 tracks 
# which contain five type 3 sectors (1024 b) + one type 2 sector (512 b)

# Now on the filesystem structure:
# The OS is found on sectors from t0s0 to t1s5, then on small sectors (s5)
# from t2 to t10
# Configuration parameters are on t11s5
# Further small sectors (t[12-79]s5) contain directory info and sequences
# I'm not interested in sequences, so I'll only take care of the samples

# A "Sound" is in fact two samples reflecting the split keyboard
# Each sample (64 sectors) is statically allocated along these lines:

# Sound   Parms Low   Lower Half     Parms Up   Upper Half
#   1       t2s0      t2s1-t14s4      t15s0     t15s1-t15s4
#   2       t28s0     t28s1-t40s4     t41s0     t41s1-t41s4
#   3       t54s0     t54s1-t66s4     t67s0     t67s1-t79s4

# The parameters sector is quite mysterious right now, but I'll check
# the Mirage's documentation to see if I can get a clue

# There is a sound "directory" sector, t32s5, where a single byte is 
# replicated 512 times because of the lack of a dedicated buffer :-)

# Bit 1 indicates Sound 1 Lower is present
#     2                 1 Upper
#     3                 2 L
#     4                 2 U
#     5                 3 L
#     6                 3 U

# Hence we have to check whether the sample is present before
# aggregating the sectors by testing the possible values of this byte
# We then separate the parameters sector from the first data chunk
# and concatenate the rest

# Up to SIX DATA FILES are created, which are named [123][LU].raw
# Work is under way to convert these using sox into something audible 

# Depends on fdutils (http://fdutils.linux.lu/)

# You have to be in the "floppy" group in order to run this program
# By default, only root can do this, so update your /etc/group :-)

# Thanks to Alain Knaff for his page http://fdutils.linux.lu/disk-id.html
# which takes a step by step approach to extract data from alien disks
# Thanks to Gary Giebler for
# http://www.youngmonkey.ca/nose/audio_tech/synth/Ensoniq-Mirage_DiskFormat.txt
# which described the gory details of the Mirage filesystem
# (This page is now missing - use the Wayback Machine)

# This program is free software. It used to be under the GPL
# but the WTFPL now seems a better match for its obsoleteness
# Also, the version was 0.3 - the code hasn't changed since

# Aggregates sector files in a sample file

concat() {
  debut=$1
  fin=$2
  fichier=$REPERTOIRE/$3
  bit=$4
  if [ $(($FLAGS & $bit)) -ne $((0)) ]
  then
    echo $fichier ok
    for j in `seq $debut $fin`
    do
      if [ -s $REPERTOIRE/d$j.dmp ]
      then
        cat $REPERTOIRE/d$j.dmp >> $fichier
      else
        # Should we append a blank sector?
        echo Warning: $REPERTOIRE/d$j.dmp is empty, no sector appended
      fi
    done
  fi
}


### MAIN ###

if [ $# -ne 1 ]
then
  echo Usage: $0 directory
  exit 1
fi

REPERTOIRE=~/mirage/$1

if [ -d $REPERTOIRE ]
then
  echo Error: directory $REPERTOIRE exists
  exit 2
fi

mkdir -p $REPERTOIRE

for i in `seq 0 79`
do
  fdrawcmd read 0 $i 0 0 3 6 0x1b 0xff \
           length=5120 rate=2 need_seek track=$i \
           > $REPERTOIRE/d$i.dmp 2> /tmp/mirage-data.err
  fdrawcmd read 0 $(($i)) 0 5 2 6 0x1b 0xff \
           length=512 rate=2 need_seek track=$i \
           > $REPERTOIRE/s$i.dmp 2> /tmp/mirage-small.err
  cat /tmp/mirage-data.err | xargs echo
  cat /tmp/mirage-small.err| xargs echo
done 

for i in 2 15 28 41 54 67
do
  dd if=$REPERTOIRE/d$i.dmp of=$REPERTOIRE/p$i.dmp bs=1024 count=1 > /dev/null
  dd if=$REPERTOIRE/d$i.dmp of=/tmp/mirage$$ bs=1024 count=4 skip=1 > /dev/null
  mv /tmp/mirage$$ $REPERTOIRE/d$i.dmp
done

FLAGS=0x`cut -b 1 $REPERTOIRE/s32.dmp \
         | od -x \
         | head -1 \
         | cut -b 11-12`

# Insert FLAGS=0x7e here if you want to extract all samples unconditionally

concat  2 14 1L.raw 0x2
concat 15 27 1U.raw 0x4
concat 28 40 2L.raw 0x8
concat 41 53 2U.raw 0x10
concat 54 66 3L.raw 0x20
concat 67 79 3U.raw 0x40

rm -f $REPERTOIRE/d*.dmp $REPERTOIRE/s*.dmp

exit 0