#!/usr/bin/python import os import sys # open trace file # read line # if -ve going edge, calculate time since last -ve edge in ns # if duration >1000ns, skip to next line # divide duration by pulse width (start at 67ns) # subtract 1 to get number of zeros after the initial 1 # add to current buffer # check start of buffer against patterns to decode # remove match and add decoded value to output # If buffer exceeds 12 bits after decode, byte-sync has been lost # (000010000000 - part of 0000100000001000) # Special case for address mark (see below) # if not in sector # search for sync field (8 pulses of 0xff) # assert Lock to Data (LTD) and Bit Sync (BITSY) # wait for another 23 pulses # calculate value of pulse width # deassert BITSY and assert Sync Address Mark (SAM) # Check for match containing 0, when found: # Count four bit positions after the 0 # Check for unique pattern flag # i.e. check for 0010000000100100 # indicates valid preamble and sync # Look for id then data # gap, ID pre-amble, ID sync, ID marker, ID data, ID CRC, ID postamble # 0x33, 0xff , 0x62* , 0xfe , ... , ... , 0x33 # data preamble, data sync, data marker, user data, data ECC, data postamble # 0xff , 0x62* , 0xfe , ... , ... , 0x33 # Output: # 33 (NN) # ff (NN) # 62 fe CC CC HH SS EE EE - Sector: Cyl/Head/Sect # 33 (NN) # ff (NN) # 62 fe - Data: # nnn\txx xx xx xx xx xx xx xx xx xx xx xx xx xx xx xx\t|................| # ECC: EE EE EE EE EE EE # Write completed sector to sect-CCCC-HH-SS as binary # Append ECC to ecc.txt as hex: sect-CCCC-HH-SS II II DD DD DD DD DD RLLTONRZ = { '1000': '11', '001000': '011', '00001000': '0011', '0100': '10', '100100': '010', '00100100': '0010', '000100': '000', '0010000000100100': '01100010', '0000100': '' } def decode_rll(pattern): """ Decode a bitstring pattern as 2,7 RLL Return the decoded bitstring and pattern remainder """ decoded = None mark = False newpattern = pattern for k in RLLTONRZ: if len(k) <= len(pattern): if pattern[0:len(k)] == k: decoded = RLLTONRZ[k] if len(decoded) == 8 or len(decoded) == 0: mark = True newpattern = pattern[len(k):] break return (decoded, newpattern, mark) def hexdump(data, start=0): """ Print hex and ascii representation of data with each line beginning with an address starting at stat """ col = 0 for pos in range(0, len(data)): if col == 0: line = "%08x " % (start + pos) asc = '' line = line + "%02x " % ord(data[pos]) if data[pos] > 31 and data[pos] < 127: asc = asc + chr(data[pos]) else: asc = asc + '.' col = col + 1 if (col % 8) == 0: line = line + " " if (col % 16) == 0: print line + '|%s|' % asc col = 0 if col > 0: if col < 8: line = line + " " line = line + " " * (16 - col) print line + '|%s|' % asc def main(): if len(sys.argv) < 2: print "Usage: %s INPUTFILE" % sys.argv[0] exit(0) if not os.access(sys.argv[1], os.F_OK): print >> sys.stderr, "Input file: %s is not accessible" % sys.argv[1] try: infd = open(sys.argv[1], "r") except IOError: print >> sys.stderr, "Error opening input file: %s" % sys.argv[1] ltd = False bitsy = False sam = False bytesync = False fault = False pulsewidth = 66.67 lastts = 0.0 syncstartts = 0 buff = '' decoded = '' output = '' synccount = 0 bytecount = 0 indata = False state = 1 for line in infd: l = line.split(',') try: ts = float(l[0]) s = int(l[1]) except ValueError: print >> sys.stderr, "Skipping invalid line in input: %s" % line continue if s == 1: # Don't care about positive going edges continue if lastts == 0: # Can't calculate duration between pulses until we've seen the first pulse lastts = ts continue if fault: err = "Fault: " if ltd: err = err + "LTD " if bitsy: err = err + "BITSY " if sam: err = err + "SAM " if bytesync: err = err + "BYTESYNC " err = err + "Buffer: %s" % buff print >> sys.stderr, err ltd = False bitsy = False sam = False bytesync = False fault = False buff = '' decoded = '' synccount = 0 bytecount = 0 hexdump(output) output = '' state = 1 # Pattern read is 1 followed by two to seven 0s patterntime = int((ts - lastts) * 1e9) patternlen = int(round(patterntime / pulsewidth)) lastts = ts if patternlen > 8: print >> sys.stderr, "Invalid pattern, more than 7 zeros (%d), Searching for new sync field..." % (patternlen - 1) print "pattern too long: %d" % patterntime fault = True continue # Append pattern to buffer buff = buff + "1" + "0" * (patternlen-1) #print buff if bitsy or not ltd: # Not locked to data - search for sync field 0xff (10001000) if buff[0:4] == '1000': if synccount == 0: print >> sys.stderr, "Got first sync nibble at: %f" % ts syncstartts = ts if state == 1: state = 2 synccount = synccount + 1 buff = buff[4:] else: print >> sys.stderr, "searchsync" fault = True continue if synccount == 8: print >> sys.stderr, "Lock To Data at: %f" % ts ltd = True bitsy = True elif synccount == 31: print >> sys.stderr, "BITSY completed at: %f" % ts bitsy = False sam = True synclen = (ts - syncstartts) * 1e9 #pulsewidth = synclen / 124 # 31 blocks of 4 pulses #print "New pulsewidth: %.2f" % pulsewidth if state == 2: state = 3 elif sam: # Search for 0010000000100100 if buff[0:4] == '1000': synccount = synccount + 1 buff = buff[4:] continue elif buff[0:16] == '0010000000100100': print >> sys.stderr, "Found SAM at: %f" % ts buff = buff[16:] sam = False bytesync = True if state == 3: state = 4 elif len(buff) < 16: continue else: print >> sys.stderr, "SAM" fault = True elif bytesync: data, buff, mark = decode_rll(buff) #print "decoded: %s, remaining buffer: %s, Mark? %s" % (data, buff, repr(mark)) if data is not None: decoded = decoded + data if state == 4 and decoded[0:8] == '11111110': state = 5 #if state == 7: #print "data: %s\tdecoded: %s" % (data, decoded) #print "buffer: %s" % buff #hexdump(output) if state == 7 and decoded[0:8] == '11111111': state = 8 while len(decoded) > 7: output = output + chr(int(decoded[0:8], 2)) decoded = decoded[8:] bytecount = bytecount + 1 #if not indata: # in ID field # if bytecount == 6: if state == 5 and bytecount == 5: # 0xfe + 4x data state = 6 elif state == 6 and bytecount == 7: # 0xfe + 4x data + 2x CRC state = 7 hexdump(output) print "Sector ID: %d/%d/%d" % (((ord(output[1]) << 4) + ord(output[2])), ord(output[3]), ord(output[4])) output = '' bytecount = 0 if __name__ == "__main__": main()