71 lines
1.9 KiB
Markdown
71 lines
1.9 KiB
Markdown
# kramer
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`kramer` is a data recovery utility for optical media.
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There are plans to change the project name, but during initial development it
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will continue to be referred to as kramer.
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This is still in very early development, so expect old maps to no longer work.
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## Plans
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### Core
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- [x] Mapping
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- [x] Record the state of disc regions.
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- [x] Recover from saved map.
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- [x] Backup old map before truncating for new.
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- [ ] Recovery
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- [x] Initial / Patchworking
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Technically there is an outstanding issue with sleepy firmware here,
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but beside that this technically works.
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- [ ] Isolate
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- [ ] Scraping
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- [ ] CLI
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- [x] Arguments
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- [ ] Recovery progress
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- [ ] Recovery stats
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- [ ] Documentation, eugh.
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### Extra
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- [ ] i18n
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- [ ] English
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- [ ] French
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- [ ] TUI (akin to `ddrescueview`)
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- [ ] Visual status map
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- [ ] Recovery properties
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- [ ] Recovery progress
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- [ ] Recovery stats
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## Recovery Strategy
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### Initial Pass / Patchworking
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Tries to read clusters of `max_buffer_size`, marking clusters with errors with
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an increasing `level`.
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This works by halving the length of the read buffer until one of two
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conditions is met:
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1. `max_buffer_size` has been divided by `max_buffer_subdivision`
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(like a maximum recursion depth).
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Effectively, it will keep running `max_buffer_size / isolation_depth;
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isolation_depth++;` on each pass until `isolation_depth ==
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max_buffer_subdivision`
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2. `buffer_size <= min_buffer_size`
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3. `buffer_size <= sector_size`
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### Isolate
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This is where we reach brute forcing territory. `ddrescue` refers to this as
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trimming. `kramer` implements the same technique. However, thanks to the
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patchworking pass, this sector-at-a-time reading can be minimized, hopefully
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reducing wear and overall recovery time on drives with a very short spin-down
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delay.
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### Scraping (Stage::BruteForceAndDesperation)
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This is the pure brute force, sector-at-a-time read. This has identical
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behaviour to `ddrescue`'s scraping phase.
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