(1) For nuclear reactors, see
small modular reactor.
(2) (
Specialized
Mobile
Radio) The communications services used by police, ambulances, taxicabs, trucks and other delivery vehicles. Throughout the U.S., approximately 3,000 independent operators are licensed by the FCC to offer this service, which provides always-on communications similar to a walkie-talkie, but over a larger geographic area. Nextel Communications is known in this field for having acquired a large number of SMR operators and turning them into a nationwide system. See
Nextel.
(3) (
Shingled
Magnetic
Recording) A hard disk recording method that overlaps the recording tracks to increase capacity up to approximately 25%. The tracks overlap each other in parallel like roof shingles; hence, the term. Seagate has been shipping SMR drives since 2013 and SMR support was added to SATA 3.3 in 2016 (see
SATA). Contrast with
CMR.