The force runs on legacy systems. Perslis runs them as they are.
Defense does not get to start over. The GAO found a Defense Department system that coordinates the operational functions of the nation's nuclear forces running on an IBM Series/1 — "a 1970s computing system" — with 8-inch floppy disks, and about 75 percent of the federal IT budget for fiscal year 2015 going to operating and maintaining existing systems (GAO-16-468, Information Technology: Federal Agencies Need to Address Aging Legacy Systems, May 25, 2016).
Replacing a fielded system takes a program. Bridging it takes a runtime. Perslis started as exactly that: a runtime that reconstructs how a legacy program works and then operates it as it is, with receipts.
What the bridge does, tier by tier
“Run any legacy system” would be a blank cheque, so here is the actual shape of it, as the legacy systems page states it:
| tier | what Perslis does | where it is shown |
|---|---|---|
| Desktop software DOS, Win16, Win32 | Reconstructed and run natively; the program's own controls are mapped into an interface that can be driven; every session carries verification receipts. | Software Preservation · white paper |
| Servers and mainframes COBOL, AS/400 | Mapped and connected through their interfaces — APIs, terminal emulation, data bridges. Orchestrated, not emulated. COBOL answers are proven by a compiler oracle or refused. | COBOL preprint |
| Legacy data DBF, Access, XLS, fixed-width text | Recovered into SQLite, CSV and JSON with hash manifests and receipts. | Liberate |
| Embedded and firmware | Read and analysed. Executing it needs the target hardware or an emulator. | Win95 USB Lab (a driver investigation) |
Why the bridge comes before the floor
A floor can only decide over facts it can read and actions it can take. The bridge turns a closed legacy system into both: its state becomes facts, read from the program's own controls and data rather than guessed, and its operations become a closed set of actions. The floor then decides which of those actions may execute — the same contract it runs in every other domain (the runtime).
Bridge, then bound, then let any intelligence lead. The legacy system stays; the floor decides what reaches it; whatever sits on top — a learned model, a symbolic planner or a crew — chooses only among admissible actions (any model on top).
What is demonstrated, and what is not
- Demonstrated: legacy Windows and DOS desktop software operated from its native controls inside isolated guests, with receipts; COBOL synthesis verified by a compiler; legacy data recovered with hash manifests.
- Not demonstrated: military data buses (MIL-STD-1553, ARINC 429, a platform's CAN bus), firmware execution on target hardware, classified networks, or any fielded system. The bridge has been exercised on commercial legacy software, not on a weapon system.
Where to start
Pick one legacy workstation workflow. We map it, run it in an isolated guest, and run the floor in shadow mode beside the operator: it logs what it would have admitted and refused, with the evidence for each, while changing nothing.