Skip to content
PatentBrief
US 2799449Freedom to Build
Public domain since 1974

You can freely build on How Alan Turing Designed Early Computer Memory Systems

This patent expired in 1974. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.

Original assignee

Nat Res Dev

Patent granted

1957

Expired

1974

Forward citations

17

What this patent covers

This patent describes a system for managing data movement between a high-speed, limited-capacity memory (like a delay line or register) and a larger, slower secondary storage medium. It focuses on the timing and synchronization required to transfer information chunks between these two tiers. By using specific control signals, the system ensures that data is correctly addressed and read or written without losing the sequence of bits. This was essential for computers that used acoustic delay lines, where data had to be constantly refreshed.

What is now free to use

All 0 claims of US 2799449 are in the public domain. Specifically:

    The 0 dependent claims add narrowing limitations and are also free.

    What is NOT covered

    Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.

    • Does not cover modern solid-state drive (SSD) flash memory architectures.

    • Does not cover graphical user interface (GUI) data management.

    • Does not cover cloud-based distributed storage systems.

    • Does not cover non-digital or purely mechanical calculating machines.

    Who is building on this today

    Modern computer architects at companies like Intel and AMD continue to refine the principles of hierarchical memory management, though they now use vastly different physical technologies like SRAM and DRAM.

    Products built on expired version of this technology

    The Pilot ACE computer

    Early mercury delay line memory systems

    How to cite this patent in your documentation

    Nat Res Dev. US Patent 2799449. Data storage transfer means for a digital computer. Granted 1957, expired 1974. Now in the public domain.

    Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.

    PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.

    ← Full patent detailsMore public domain patents →