US 5608448

Summary: US Patent 5,608,448 (US5608448A)

Search note: I searched for the exact patent number "5608448" only (per your instruction not to auto-correct identifiers). Results confirm the Google Patents full text provided. No CAFC 2026 docket entries or USPTO litigation records referencing patent 5608448 were found in either search; given the patent expired in 2015 (20 years from the April 10, 1995 filing), it is not expected to appear in active 2026 Federal Circuit litigation. I have no authoritative source showing any current or historical CAFC appeal for this patent.

Bibliographic data (verified against Google Patents, Justia, FreePatentsOnline, and USPTO.report)

Abstract (verbatim from the patent)

Processing requirement at each computing element in a video server for a video on demand (VOD) system are reduced to only those needed for VOD, resulting in a less expensive processor with less memory and, hence, lower cost. A hybrid video server architecture combines the best features of massive parallel processor (MPP) and workstation designs into a cost effective high performance system. Since it is not necessary to run a parallel relational database program in order to accomplish VOD data distribution, a unique type of switch element that is well matched to the VOD server problem is employed. By matching this switch element technology to an appropriate data storage technique, a full featured, responsive VOD server is realized that can be affordably installed at regional cable distribution centers nationwide.

Independent claims in plain language

The patent has 10 claims total — two independent claims (claims 1 and 8) and eight dependent claims.

Claim 1 — VOD server apparatus. A video-on-demand server that supplies digitized movies to subscribers through a distribution network, made of three components:

1. A disk array storing many digitized movies, where the movies are spread ("striped") across multiple disks organized into multiple partitions;
2. A multiprocessor switch array built from many processing elements, each element having its own CPU and local memory — the local memory holds switching information used to route requested movies to the requesting subscribers; and
3. A workstation connected to the switch array that responds to subscriber requests, assigns each subscriber to one of the disk-array partitions, and controls the individual switches in the array so that requested movies are delivered on demand.

In essence: a hybrid server where a general-purpose workstation handles control/assignment logic and a massively parallel array of CPU-equipped switch elements (not just passive crossbar hardware) performs the high-speed switching, with movies striped across partitioned disks.

Claim 8 — VOD distribution system. A complete end-to-end video-on-demand distribution system comprising:

1. The VOD server (the same disk array + multiprocessor switch array combination as claim 1, but with the switch array expressly specified as a Benes network of 2×2 switch elements in a minimal topology), including the workstation that assigns subscribers to partitions and controls the switches;
2. A distribution system connecting the switch array to multiple subscriber terminals; and
3. Decoders connected to the subscriber terminals that decode the digitized movies for display on a television set or monitor.

In essence: claim 8 adds the delivery-side infrastructure (distribution network, subscriber terminals, and set-top decoders) and explicitly requires the Benes-network switch topology, capturing the full system rather than just the server.

Dependent claim map (briefly)

• Claims 2–7 depend on claim 1: claim 2 (Benes network of 2×2 elements), claim 3 (pairs of 2×2 elements formed as binary hypercubes), claim 4 (each hypercube on a single chip), claim 5 (each partition stores complete movies in data blocks), claim 6 (sequential rotation reading one block from each disk per partition), claim 7 (virtual VCR functions: play, pause, fast forward, rewind).
• Claims 9–10 depend on claim 8: claim 9 (hypercube 2×2 pairs on single chips), claim 10 (rotation reading plus virtual VCR functions).

Uncertainty / confidence statement

• The bibliographic data, abstract, and claims are confirmed by multiple independent sources (Google Patents, Justia, FreePatentsOnline, USPTO.report) and the authoritative full text you supplied — high confidence.
• The assignee chain (Loral → Lockheed Martin Federal Systems → Lockheed Martin Corp.) comes from Google Patents assignment events; the exact entity name at grant is listed as Lockheed Martin Corporation by Justia — minor naming uncertainty in the historical chain.
• No CAFC 2026 docket or USPTO litigation record for patent 5608448 was located. I cannot rule out a docket entry that is not indexed by the search tools used, but based on the expiration date and search results, no pending 2026 litigation is known.