Relocate the shared low-level primitives into a single crypto module:
aes_ecb_encrypt/decrypt, aes_cbc_decrypt, aes_g (from content/variant) and
aesg3 + AESG3_SEED (from keys), plus AACS_IV. Fixes the scatter where AES-G
lived in the 2.1 file and AES-G3 in keys. Relocation only — no rename, no
logic change (logic-hash identical to baseline; 277 items; 2210 tests green).
Pure file+module-path rename. 'content' names the AACS unit-decrypt layer
(distinct from the top-level sector-decrypt driver crate::decrypt), and
'variant' (singular, spec term 'Media Key Variant') names the 2.1 chain.
Logic-hash identical to baseline; 277 items intact; tests green.
Add [C]/[PR]/[BD]/[libaacs] §x.y provenance markers across the AACS
crypto so each primitive links to the spec section it implements, with a
source-tag legend in mod.rs. Doc-comments only — no logic, constant, or
signature changes.
Also: correct two stale record-type comments in variants.rs (0x82/0x83 →
the real 0x2d/0x2f) and document the Variant Number width (spec lsb_10 vs
the 2.1 chain's lsb_16, driven by the 65,535-entry VKD table).
The Media Key Variant scheme is detected and parsed via the actual MKB
record types found on a real variant disc:
- 0x2d Encrypted Media Key Variant Data (C)
- 0x2f Variant Key Data table (65,535 x 16)
- 0x0c variant cvalues (one per 0x04 subset-difference slot)
Replaces the earlier placeholder 0x82/0x83 record types, which were a
guess and appear on no real MKB. is_variant_mkb, the record finders, and
the subset-difference cvalue source (now 0x0c, falling back to 0x07/0x05)
are updated accordingly, along with the V20->V21 upgrade detection in
resolve_keys_v2 and its fixtures.
The variant chain still halts at variants_for_uv (the VARIANTS[uv] /
Nonce sub-field offsets need a covering key to confirm end-to-end
against the 0x86 verify), so a best-effort offset is never silently
trusted. All 27 variant tests pass on Rust 1.86.
A Processing Key is the key at its Subset-Difference node — one AES-G from
the Media Key — so it is tried directly against the MKB cvalue tables,
matching libaacs _calc_mk_pks (iterate PKs × cvalues). The prior code
treated every PK entry as a device-node label at unknown depth and BFS-walked
the SD tree (depth 3, capped 5), which was both wrong for terminal PKs and
~15x slower on a large UHD MKB (~181k cvalues): PK derivation on UHD dropped
from ~37s to ~2.4s.
The Subset-Difference tree walk now lives solely in the device-key path
(derive_media_key_from_dk), which owns per-node path bits; the PK path never
descends. Removed PK_WALK_MAX_DEPTH / _CAP / _walked / walk_pk_against_tables_impl;
renamed the core scan try_pk_against_tables and its probe test.
Precommit (Rust 1.86): fmt + clippy + tests green.
resolve_candidate(candidate, mkb, unit_key_ro, vid) -> ResolvedChain: one
composed, PURE-DERIVATION boil-down for a candidate key at any ladder rung
(KeyCandidate::{Uk,Vuk,Mk,Pk,Dk}, each carrying the module's newtype). Walks
DK/PK/MK/VUK -> terminal unit keys, parsing Unit_Key_RO.inf at the version
the disc's MKB declares, and returns every CPS unit key as (cps_unit, key)
(matching ResolvedKeys) plus the intermediate chain. No sampling/validation
(that's the caller's unit_key_validates) and no position recovery (Dk is a
positioned DeviceKey; recover_dk_position first). Adds ProcessingKey newtype.
Consumers stop re-composing the ladder; every client hardens one impl.
Correct mk_from_dk: real Subset-Difference walk (derive_media_key_and_pk_from_dk)
instead of the Media-Key-Variant path, which needed integrator KCD absent
in-tree and Err'd for every real disc -- dead for both consumers. Drops the
now-unused vid arg.
The first cut used a global running clock (max(next, own-PES PTS) + advance),
which fixed the same-PES collision but DRIFTED: once accumulated frame
durations exceeded the PES-timestamp spacing, it never re-based, so a
feature-long DVD DTS track ran minutes past its real length (2h44 for a 2h03
film) while AC-3 from the same source stayed exact.
Match the AC-3 path: re-base to each PES's own container timestamp, and advance
by one frame duration ONLY within a run of AUs sharing one PES. Fixes the DVD
multi-frame-per-PES collision without drift; the UHD DTS-HD MA per-PES
attribution (da85f56) is preserved (each AU still takes its own core PES's PTS).
Adds new_pes_rebases_to_its_own_pts_no_drift; full mux suite green (905).
DVD packs several DTS core frames into one PES; the parser stamped every
access unit with that single PES PTS and duration_ns=None, so consecutive
frames collided on one timestamp — ffmpeg rejected the output as 'non
monotonically increasing dts to muxer: X >= X' (deep-decode = corrupt,
e.g. The Punisher). The UHD DTS-HD MA path (one AU per PES, distinct PTS)
was unaffected, which is why this only surfaced on DVD.
Parse the DTS core header for samples ((NBLKS+1)*32) and sample rate
(SFREQ, 48kHz fallback) to derive each AU's duration, and stamp a running
monotonic PTS: max(next_clock, own-core-PES PTS), then advance by the
frame duration. A later PES whose PTS is ahead of the clock still wins
(preserves the UHD per-PES attribution from da85f56/c49a180); frames
sharing one PES advance frame-by-frame instead of colliding.
Tests: the 3 that encoded 'same PES -> same PTS' now assert monotonic
advance; new dvd_many_cores_one_pes_are_strictly_monotonic reproduces the
Punisher bug; duration/SFREQ-fallback unit tests added.
The tier ladder (bucket->mug->thimble) forces tier 0 to attempt ALL
ranges before tier 1, and tier 1 all before tier 2 — so on a hardened
residual (late resume, flood already gone) the marginal specialists are
unreachable for hours: you bail near-empty buckets over hundreds of dead
ranges before a thimble ever touches water.
FREEMKV_PATCH_FLAT collapses the 3 tiers into ONE flat pool of all 16
handler configs. run_handlers already sorts best-first by the live
decayed-yield scorecard, so this is a data-driven bandit: the first
ranges try them all (explore), the ranking floats whatever is actually
landing sectors to the front (exploit), re-measured per range; a handler
that doesn't fit stays last but is never dropped (floor -> can revive).
The new handlers self-limit (yield after 4 dead reads), so the flat
scheduler does NOT reintroduce the old depth-first per-range starvation.
Opt-in; unset keeps the proven tier ladder as the default for 1.2.0.
The tier-2 marginal specialists now additionally probe permanently-bad
residual sectors before leaving them NonTrimmed, so the alternating-bad
profile's finite read count rose past the old tier-0/1 bound. Guard
still catches runaway; behavior asserts unchanged.
Add a third breadth-first tier (PATCH_TIERS 2->3) that runs the marginal
specialists on the hardened residual tiers 0-1 leave: SlowSpin (Linear
fwd+rev @ min), FuaRetry (Linear fwd+rev+Bisect @ FUA), SlowFua (Linear @
min+FUA), CachePrime, Oscillate (@ max and @ min), SpeedSweep. Every read is
a wedge-safe read_span, so they inherit wedge-abort / unproductive-yield /
deadline for free. All are new configs, so the EWMA scorecard calibrates each
once then ranks by decayed rate — a specialist that doesn't fit self-
deprioritises. Tiers 0-1 (fast scouts, slow-deep) are unchanged; this is
purely additive. Also switch the scorecard log sort to sort_by_key.
cargo test -p libfreemkv green (2200 passed).
CachePrime reads the good run immediately preceding a residual island to lock
the servo/PLL, then reads the island warm (boundary sectors the drive can't
cold-seek). Oscillate reads each residual sector by alternating approach —
forward-into then reverse-into — for direction-dependent tracking. Both go
through the wedge-safe read_span (primes included). FakeDisc models a
direction-dependent sector and a servo-primed boundary sector; fixtures prove
a forward/cold Linear misses each while Oscillate/CachePrime recover them.
FuaRetry (Linear fwd+rev+Bisect at {max,fua,deep}) and SlowFua (Linear at
{min,fua,deep}) are Linear/Bisect at FUA params, no new struct. FakeDisc now
models a stochastic sector that lands only on the Nth physical (FUA) read (a
cached re-read keeps missing) and a hardest sector needing BOTH min speed and
FUA. Fixtures prove cached reads keep missing while the FUA group lands the
stochastic sector, and that neither lever alone recovers the hardest sector —
only the min+FUA combination does.
SlowSpin is Linear pinned to min speed (no new struct). SpeedSweep is a new
per-sector handler that tries Max->Min until one reads (speed resonance).
FakeDisc now models a sector that reads ONLY at min speed; fixtures prove a
max-speed Linear misses it while SlowSpin and SpeedSweep recover it (and that
SpeedSweep tries fast-then-slow).
Grade handlers by an exponentially-decayed recovery rate (bytes/second,
alpha=0.5) instead of a cumulative rate. The residual hardens mid-pass, so
the best technique changes: cumulative froze the early winner in the lead
forever; the EWMA re-prices continuously — a handler that stops earning
decays down, a late-starting specialist climbs. Keeps rank()'s untried->top
one-shot calibration and attempted-but-zero-time->bottom.
New flip fixture proves a handler that recovers a lot early then nothing
loses its lead to one that starts recovering later.
Add ReadParams { speed: SpeedPref, fua: bool, timeout: TimeoutPref } and
thread it through read_span so every wedge-safe handler read can request a
spindle speed (SET CD SPEED issued only on change, restored to max when the
handler exits), set the READ(10) FUA bit, and pick the 10s vs 60s timeout.
- SectorSource gains read_sectors_fua (default ignores fua); Drive sets the
CDB bit, DecryptingSectorSource threads fua to its inner read.
- recovery_read gains a fua param.
- Linear becomes { direction, params }; Bisect/Jump take params. Existing
tier-0/1 instances keep identical behavior (max speed, no FUA, fast/deep).
- Scoreboard keys on the full-config String name (linear:fwd:max:fast, ...).
- FakeDisc observes speed + FUA + approach so specialist techniques are
provably exercised in later commits.
cargo test -p libfreemkv green (2193 passed).
The private_stream_1 sub-stream id low nibble is the DVD audio-stream
NUMBER (0-7), shared across codecs, not a per-codec ordinal. A DTS (or
LPCM) track that isn't the disc's first audio stream got a sub-id one
too low, so the demux routing key (0xBD00 | sub_id) never matched and
every packet was dropped -> present-but-silent track. AC-3 at position
0 coincidentally worked (ordinal==position). Route by positional index.
Fixes silent DTS 5.0 track on The Punisher (AC-3 5.1 @ pos0 plays,
DTS 5.0 @ pos1 was 0xBD88, real wire id 0xBD89).
Delete src/verify.rs (standalone 'read every sector, classify health'
module) + its lib.rs pub mod/pub use. It was old, unused code. The
decrypt-verify gate (disc::verify / UnitVerifier) is a DIFFERENT module and
stays. Relocated the pure chapter_at_offset helper (used by locate_ranges +
autorip's done-card) into disc/mod.rs as a pub fn.
- Live located drilldown (sweep + patch progress snapshots) now excludes
NonTried, matching the one-shot path. Including the unread remainder made
main_at_risk_ms show ~full-movie at sweep start and melt to 0 as it
progressed — unread is unknown, not damage.
- Wedge abort now requires the failure to be FAST (< WEDGE_FASTFAIL_MS,
500ms) as well as wedge-family sense: a real uncorrectable sector on
Hardware-error media spends ECC-recovery time before failing, so it no
longer false-trips the fast-fail wedge abort. New regression test.
- Removed the always-zero blocks_attempted/read_ok/read_failed/
unreadable_count from PatchOutcome + PatchLoopState (dead residue from
the old grind loop; the HandlerScoreboard supersedes them) so the
patch.done log no longer emits misleading zeros.
yes now means the unlocker actually ran and did its job: LibreDrive from
the runtime firmware-unlock success, AACS host-cert only when LibreDrive
didn't do the bus (stock-drive fallback), CSS from the crack succeeding.
On a LibreDrive UHD that correctly reads LibreDrive: yes, AACS: no (LD
removed the bus, the cert route never ran) instead of the misleading
AACS: yes. Names stay registry-driven; runtime logic lives here.
Forcing FUA (Force Unit Access) on EVERY READ(10) bypassed the drive's
readahead/streaming cache on the bulk Pass-1 sweep, collapsing sequential
throughput ~10x (UHD 15-25 → ~2 MB/s, DVD → ~0.5 MB/s), disc-type-
agnostic — the cache IS the streaming throughput. This was the real speed
regression (not unlock/riplock, which the earlier chase suspected). Clear
byte-1 bit 0x08. FUA will return as a dedicated Pass-N recovery handler
that sets/clears it per marginal-sector re-read, where cache-masking of a
stochastic sector actually matters — never blanket on the bulk path (#55).
Returns each registered unlocker's name + whether it applies to this
drive+disc (via the unlock bridge over all_unlockers()). Disc crypto kind
derived in the library so the CLI and autorip render an identical, always-
current report with no hardcoded names. Also adds a Drive::unlocker_name()
runtime getter.
The v1.0.0-rc.1 unlocker refactor added an `if disc_is_dvd() { return }`
early-return in Drive::init() that skipped the whole drive-prep unlock for
DVDs. That firmware unlock is what lifts riplock and readies max read
speed — a DRIVE-level, disc-independent feature — so skipping it left
every DVD stuck at stock/riplock speed (~0.4x, 3h ETA). UHD was unaffected
because it flows through the unlock.
Remove the skip: init() now runs the identity-keyed drive unlocker for all
discs (disc kind is Unknown at init, so only the drive unlocker matches;
the AACS host-cert handshake and CSS bus-auth still run later, gated on the
real disc kind, on top of the unlocked drive). Speed stays where it
belongs — SET CD SPEED(0xFFFF) at pass-1 start (disc/mod.rs) — not in the
unlocker. Also drop the matching probe_disc DVD skip.
Reverts the SET STREAMING stopgap (separate freemkv-unlock revert): that
treated the symptom; the real bug was the skipped unlock. Drive features
come from the firmware unlock, not a stock speed CDB.
Handlers (section_recover.rs):
- Bisect expand loops now honor ctx.halted() (were deadline-only, so a
Stop could hang up to 60s vacuuming a readable island).
- read_span: explicit Transport arm so a bus-abort read isn't counted as
unproductive grinding; debug_assert the sector-aligned span invariant.
- Scoreboard rank: an attempted-but-zero-time handler (e.g. returned Halted
on its first check) now ranks BOTTOM, not top — it no longer crowds out
proven performers.
- Document the wedge tier-size coupling + new regression test that a
2-handler (tier-1) chain still catches a wedge via cross-section streak.
Pass-N engine (patch.rs):
- Rebuild PatchOutcome stats AFTER the post-read re-verify downgrade flush
(was snapshotting before it, over-reporting bytes_good / recovered and
risking a 'perfect rip' verdict on an imperfect one).
- Progress 'recovered' composes the still-bad set to MATCH work_total
(subtract NonTried, add Unreadable) so the bar can't pin at 0 on a
partially-swept disc or run backward on the Unreadable→NonTrimmed relabel.
- Remove dead work_done field; rewrite the stale 'adaptive batching' comment
to describe the handler chain and mark block_sectors/full_recovery as
informational-only.
Sweep (disc/mod.rs):
- Saturating arithmetic at the damage-jump position math (honor the
read_error side's documented defence-in-depth guarantee).
Deferred (noted, need focused passes): fast_capture re-introduction,
Pass-1 halt-misclassified-as-jump, bytes_good display inflation, the
always-zero blocks_* telemetry, Pass-1 jump-on-first-error policy.
DVD ran the drive at ~0.4x stock speed: init() early-returned for DVD
before any speed was set, and its only speed command was the sweep's lone
legacy SET CD SPEED, which this BU40N ignores for DVD. BD/UHD got up to
speed only via the firmware unlocker's calibration — a path a DVD can't
take (it breaks stock CSS).
Call the new unlock-crate drive-features capability at init() for ALL disc
kinds, before the DVD stock-mode early-return, via a bridge shim. Stock
MMC only (SET STREAMING + SET CD SPEED), no bus unlock, so CSS is
undisturbed.
The 2026-07-01 overnight rip ground a wedged BU40N for 28 minutes at
0 B/s. Root cause: the handler chain's read_span split errors only into
Transport (bus gone) vs Bad (everything else), so the drive's fast-fail
wedge sense (ILLEGAL REQUEST 0x05/0x24 — it rejects every CDB in <100ms
without attempting recovery) was treated as an ordinary bad sector. The
chain hopped to the next section forever, and the existing wedge detector
in read_error.rs never saw it because the chain reads through
recovery_read directly.
Add a pass-level wedge streak: read_span counts consecutive wedge-family
(Hardware/IllegalRequest) senses; at WEDGE_ABORT_STREAK (16) it escalates
the read to Transport, which every handler already propagates as
TransportFault — aborting the whole pass and setting wedged_exit so the
caller spin-cycles. The streak is carried across sections via PatchCtx
(seeded into and read back from each per-section HandlerCtx) so a wedge is
caught even when every bad sub-range is smaller than the streak. Any Good
or non-wedge (medium-error) read resets it, so scattered bad sectors on
real media never trip it. New fixture test: a wholly-wedged 1000-sector
section aborts in <100 reads, not 1000.
The expand loops broke out of the batch sweep on the first failing read,
overshooting the good/dead boundary by up to a batch and leaving the
readable sectors adjacent to a dead edge for the re-bisect to re-pin. On
top of that, early-yield counted those boundary-probe failures as a
stall, so the forward expand quit early AND the backward expand inherited
a poisoned unproductive counter and yielded instantly.
Now on a failed expand batch we halve the step (down to a single sector)
to recover right up to the dead edge in ~log2(batch) reads, drive the
expand loops off the deadline only (they self-terminate via halving), and
clear the unproductive streak once an island is located. patch_recovers_
good_middle_of_a_bad_range now recovers 50/50 good-middle sectors.
Scorecard: grade each handler by recovery rate (MB/s) per rip, order
best-first on later sections, log the ranking at pass end. Untried
handlers rank top so each is calibrated once before ranking narrows to
the winners. Ephemeral (reset per pass), no persistence.
Tier 0 scouts are now [Bisect, Jump, Linear-fast x2], scorecard-ordered.
Bisect leads: probing the MIDDLE of a range lands on a readable island in
one read where a linear scan grinds the dead front to reach it. Jump now
jumps to the middle of the REMAINING span (proportional) instead of a
fixed 8 MiB that leapt clean over small ranges and missed their readable
middles. Tier 1 is slow deep-recovery on the residue.
Scorecard (ephemeral, reset each pass, no persistence): grades every
handler by recovery rate (bytes/sec). run_handlers orders handlers
best-first by that rate; an untried handler ranks top so each is
calibrated once, then the ranking narrows to the winners. Logged at pass
end (phase=scorecard) so the operator sees which handler is pulling the
weight on this drive/disc and which is a dud.
Tier 0 scouts are now [Bisect, Jump, Linear-fast x2], scorecard-ordered.
Bisect leads because probing a range's MIDDLE lands on a readable island
in one read, where Jump (linear from the front, big skip) can grind the
dead front or overshoot a small range entirely. The scorecard confirms
or overturns that order with real per-disc data.
Each dead probe read costs the drive's full ~10s timeout, so a large dead
region took a dozen escalating probes. Starting the jump at 8 MiB (vs
1 MiB) clears it in a handful; a skipped span stays bad for Bisect to
reclaim readable islands, so an over-jump loses nothing.
Tier 0 is now a single fast Jump scout: it streams the big readable
ranges back and skips dead runs in seconds, so the pass reaches every
section fast and converges to the small genuine-dead residue instead of
grinding three handlers x 60s on each dead fragment. Tier 1 (fast
mop-up + slow deep reads + Bisect) works only that residue.
Bisect now expands: on a good probe it reads outward forward and
backward in full batches until a read fails, recovering the whole
readable island in large reads; the two failing ends become smaller bad
sub-ranges it bisects again. One huge bad range becomes many precisely
located small dead clusters.
Progress heartbeat: HandlerCtx gains a throttled tick (250ms) called
from every read, pushing a fresh snapshot to the reporter DURING a
handler. The bar and speed now move continuously as recovery happens
instead of jumping once per section (the reason speed read 0 B/s and the
% looked frozen between range boundaries).
Jump: on sustained batch failures skip ahead an escalating distance
(1 MiB doubling to 256 MiB) to find where readable data resumes, leaving
the skipped span for Bisect to pin — mirrors the Pass-1 damage-jump. It
leads the fast tier so a large dead run is skipped in seconds instead of
the linear sweeps grinding every dead batch (10 s each) first; on a
readable range it just streams it back. Recovers readable data buried
behind a big dead front (the 192 MB Dune range).
Progress %: report bytes RECOVERED (initial-bad minus still-pending)
instead of a per-range counter that only advanced on the final tier — so
the bar reflects the readable bulk recovered during tier 0 the instant it
lands, matching the 'MB remaining' number.
The per-range walk was depth-first: each bad range ran the full handler
chain (fast + slow deep-recovery + bisect) before the next range was
touched. So a handful of tiny dead fragments at one end of the disc
burned the whole pass and the big NonTrimmed ranges elsewhere — usually
sweep-jump over-marks that read straight back — were never attempted.
Now recovery runs in two breadth-first tiers over ALL sections:
- Tier 0 gives every section one fast full-batch attempt (fast reads
only), largest ranges first, so the recoverable bulk of the disc comes
back in the first minutes.
- Tier 1 deep-recovers only the residue tier 0 could not pull.
Per-section still-bad sets persist across tiers. Largest-first ordering
means a big readable region is reached before time is spent on tiny dead
fragments.
Linear no longer collapses a failed batch to count=1 single-sector reads
(live probing: a marginal sector recovers in a large read, not a lone
one) — a failed 32-batch stays 32 and is re-attempted at full size by the
next handler/pass; Bisect salvages readable islands.
Adds a handler-start trace line so the debug log shows which handler is
running and the hand-off to the next.
Pass-N recovery is now a chain of time-bounded recovery handlers instead
of one monolithic per-range loop that could grind the front of a bad
range for up to 30 min, wedge the drive, and abort the whole pass.
A bad range is a SubRanges set; recovery is an ordered list of
SectionHandlers (Linear{reverse,fast} covering back/forward x fast/slow,
and Bisect). A coordinator runs each handler with a hard per-handler
deadline: a handler recovers what it can (removing it from the still-bad
set) and hands the rest to the next handler; whatever is still bad after
the chain becomes NonTrimmed residue and we move on to the next range.
Guarantees, now structural rather than bolted-on:
- never hangs: every handler is deadline-bounded; the loop always drains
to recovered-or-residue.
- always moves on: a range that cannot be finished leaves residue and
advances; only a genuine transport fault or user halt ends the pass.
- extensible: a new recovery idea is one SectionHandler impl added to the
chain; a proven-ineffective one is removed. The engine never changes.
Removes ~1.9k lines of the old inner loop (watchdogs, skip escalation,
NOT_READY grind, wedge counters) and their tests. fast_capture is now
inert (the chain supersedes it); breadth-first ordering becomes a future
scheduler concern. New module: disc/section_recover.rs (8 fixture tests,
injectable clock — bounded/never-hang proven without touching a drive).
Two A/B tests updated to the chain's strictly-better recovery counts.
Every Drive::read now forces the read from physical media instead of
letting the drive satisfy it from cache. A recovery tool must not trust
the cache: on a re-read of a marginal sector the BU40N can return a
cached miss (~4 ms) instead of giving the surface a fresh physical
attempt (~40-250 ms), masking a sector that would otherwise read on a
real media hit. FUA (READ(10) byte 1 bit 3) is validated on the
BU40N/Initio bridge.
Spin the disc down (START=0, LOEJ=0) then back up (START=1) to clear the
BU40N/Initio fast-fail wedge state a run of HARDWARE_ERROR reads leaves the drive
in — the non-eject power-cycle our notes say the wedge needs. The disc stays
loaded; we never eject (slot-loading — a human eject is a product failure for an
unattended service). Validated live 2026-07-01: took the drive from
failing-every-read back to reading at MB/s.
A fast_capture pass defers every failed block to a granular pass anyway, so
spending the drive's 60s deep-recovery timeout on it here only freezes the
breadth-first sweep on a pure-bad cluster (~25s per 32-block, incl. NOT_READY
grind). Read with recovery=false in fast_capture so a bad block fails on the
short timeout (~10s) and the sweep steps on; the granular passes
(fast_capture=false) do the deep recovery on what's left. No recovery lost —
the block stays NonTrimmed for the granular retry.
A PatchOptions.fast_capture pass reads each bad range ONCE at the full batch and
leaves every FAILED block NonTrimmed for a later pass — no bisect, no per-sector
grind, no retry. This lets a first retry pass grab the readable blocks (the
sweep's good skip-ahead overshoot) of EVERY section quickly, before any single
section's slow per-sector recovery — instead of grinding section 1 to exhaustion
before even touching section 2. A later pass (fast_capture = false) does the
granular bisect/retry on what's left.
Load-bearing invariant (fixture test): NO data is dropped. A failed block becomes
NonTrimmed (pending, retried by a granular pass), NEVER Unreadable. The test pins
that the readable half of a range recovers, the bad half stays NonTrimmed (not
Unreadable), and the bad block is marked in ONE batch read with zero bisection.
Disc::copy's internal patch keeps fast_capture=false (single-call full recovery).
Matthew Jackson
matthew