Documentation / Storage formats
Storage formats
DBF_64 and FPT64 — what widened, what did not, and where the gates still are.
Three flavors, one runtime
Runtime-proven The same binary opens classic MS-DOS-era DBF, Visual FoxPro DBF, and the x64 DBF_64
format. Flavor is a property of the table on disk, not a compile-time choice. The teaching datasets
ship in all three plus a reference copy, so a lesson can put them side by side.
What x64 actually widened
- Table headers carry 64-bit record-count and geometry fields
- Memos use 64-bit object identifiers and offsets
- Metadata supports richer table and field names, with classic descriptor fallback tokens preserved
What has not been widened yet. Some shared runtime paths still carry compatibility gates that must be audited one at a time, and each index backend needs its own audit for true 64-bit record payloads and offsets. x64base does not claim every command path is unlimited. Source-evidenced
Memos
Source-evidenced Memo storage is payload-agnostic by design: the memo layer addresses objects by 64-bit identifier and does not inspect what they contain. The interesting destination built on that — a memo field carrying an entire small database as a teaching payload — is Chartered and stated at exactly that tier: designed, not run.