Supertape (Input64 Diskmagazine)
================================
  info by Andreas Matthies <andreas.matthies@arcormail.de>


Encoding:
---------

Three different pulses are used (not 100% accurate)

  Short  (s):           464 T-States ~ 261 cycles of C64(PAL)
  Middle (m):           703 T-States ~ 396 cycles of C64(PAL)
  Long   (l):           945 T-States ~ 532 cycles of C64(PAL)

A pulse s represents a Bit0.
A pulse m first represents Bit1Bit0 (two Bits) then Bit1(one Bit), then again
Bit1Bit0 and so on.
A pulse l represents Bit1Bit1 (two Bits) and resets the counter for the m
pulses, means that the next m following an l is always Bit1Bit0.

Each Data Byte has 8 Bits with least significant Bit first.

Lead-In Byte is $16 and Sync Byte is $3A (or $2A; the byte is masked with $EF
and compared to $2A)
for the header-block and $C5 for the data-block.

Structure:
---------

Each file consists of two blocks, the header and the data. Each block follows a
lead-in, which is at least 11 bytes of $16. The structure of the header is:

$00 - $0F: filename
$10 - $10: #00 (not used?)
$11 - $12: start-adress
$13 - $14: length of file
$15 - $18: #00 (not used?)
$19 - $1A: parity-checksum, should match the amount of Bits1 in $00-$18.

The strucure of the data-block is even more simple:

$0000 - ...: data
followed by two bytes parity-checksum, that should match the amount of Bits1 in
data modulo $10000.