# Delete me after these things are fixed

Temporary notes from the SBFS v2 and CosmOS review, in priority order.

## Bound the number of directory entries

The parent field is 16 bits and stores `descriptor index + 1`, with zero reserved for the
root. Descriptor index 65535 therefore cannot be represented as a parent because adding
one wraps to zero. SplitDisk currently accepts directory sizes large enough to exceed the
representable parent domain.

Define and validate a maximum directory-block/entry count such that every directory entry
can be named as a parent. Apply the check while formatting and mounting/reading malformed
images in both implementations.

## Design strengths worth preserving

- Parent-as-index-plus-one makes every version one entry a valid root child without
  conversion.
- Directories consume one descriptor and no data blocks, leaving the descriptor array as
  the complete allocation map.
- Files remain contiguous and the block allocator remains ignorant of hierarchy.
- Path resolution below the service boundary gave existing applications directories
  without changing their interfaces.
- The current directory is a two-byte identity rather than a stored string, and the shell
  restores it after applications run.
- The independent host/native implementations and byte-identical disk agreement tests are
  unusually strong validation of the written format.
- `osFileStart`/`osFileWrite`/`osFileFetch`/`osFileDone` provide the bounded-memory output
  abstraction needed by assemblers, compilers, linkers, and future sequential pipelines.