These changes should not impact reading/writing from real disks. This
includes a bug fix to Fluxmap where it might miss a trailing interval
when adding bits, as mentioned in #333.
With the Fluxmap bug fixed, the encoder now includes index pulses in its
output. The decoder was relaxed to allow reading precisely one track.
We don't actually add an encodedecodetest for micropolis, though,
because the SCP encoder is unhappy with so many revolutions.
formatspecs, making for much cleaner code. Reformatted everything.
This actually happened in multiple steps but then I corrupted my local
repository and I had to recover from the working tree.
seekToPattern() can skip the index hole if it doesn't find the
SYNC pattern. If this happens too close to the end of the flux
stream, it can result in a conflicted sector. In this case,
discard the sector.
Vector MZOS uses a different sector checksum than the standard
Micropolis checksum used by MDOS, CP/M and OASIS. Automatically
detect the checksum on the disk by default, but allow the user
to force the use of a specific checksum using the
--decoder.micropolis.checksum_type parameter.
* Discard a partial sector at the end of the track.
* Do not seek to the index mark for the first sector.
* Use a 64-bit pattern to match the SYNC.
* If SYNC is found too early, search for a subsequent SYNC.
* While decoding the sector record, enforce the SYNC pattern
and track ID.
fluxmap. This requires resetting the FluxDecoder, which loses any pending
state, resulting in bad reads for (some) formats which don't have gaps between
sectors --- the DVK MX is the main victim.
Two bugs make a right, mostly. The very last carry should be ignored and
when adding the low and high bytes they commonly would commonly produce
a carry which was being ignored. On the test disks these two bugs
cancelled themselves out, except only for track 1, side 1, sector 0. I
had noticed it was suspicously off-by-one earlier for both test disks,
but the cause wasn't obvious.
On some old 1980s disks, with real data, it changed number of bad
sectors from 224 (out of 2464) to 5 for one disk and 81 to 3 for
another.
