arfarf's New Writeups

MIDI running status (idea)

2002-11-23T08:02:59Z

MIDI 'events' are transmitted using strings of bytes. Each event can be sent as a MIDI status-byte (value 128 to 255 decimal) followed by one or more MIDI data-bytes (value 0 to 127).

The purpose of the status-byte is to describe the kind of data that is about to be sent. Generally, the same number of data-bytes is sent after each particular status-byte

Often, the same kind of data is sent repeatedly, and sending the status-byte repeatedly would be redundant and reduce the bandwidth of the MIDI stream. Examples would include a series of MIDI note-ons or MIDI pitch-bend events.

So most modern MIDI hardware (e.g. synths) and software use 'running-status'. It's assumed that, once the expected number of data-bytes has been sent/received, IF the next byte is *not* a status-byte, THEN the last status-byte received should be used to decipher the following data bytes.

Typically this results in about a 1/3 reduction in the number of bytes sent.

Coordinated Universal Time (thing)

1999-11-13T14:40:51Z

Clock readings are provided by two US time agencies, the National Institute of Standards and Technology, NIST, and its military counterpart, the U. S. Naval Observatory, USNO. These readings contribute to world time or UTC. Very accurate times are maintained with atomic clocks.

UTC can be heard on Colorado shortwave station WWV at 2.5, 5, 10, 15 and 25 MHz. Or you could just bip over to www.time.gov.

cacao (thing)

1999-11-13T14:39:45Z

Chocolate bean of South America, which the Mayans and Aztecs ground into hot water and drank. They also used it as currency.

The beans grow on a tree cacao theobroma pollinated by midges and bats. Each pod contains 20 to 50 beans.

Columbus brought cacao back to Europe in 1502. It wasn't popular until they learned to add sugar to it.

Oscar satellite (thing)

1999-11-13T14:39:34Z

One a long series of generally low-earth orbit satellites constructed and operated by amateur radio operators. Most were accessible to any radio ham for experiments and communications, with relatively low-cost equipment.

To date well over 30 Oscars have been orbited, including AMSAT-OSCAR 10, operating since its launch in 1983.

Packet radio (thing)

1999-11-13T14:39:33Z

A form of radio communications popular in amateur radio. Commonly uses the AX-25 (or sometimes TCP/IP) protocol to transmit short packets of characters, which can be repeated if not received correctly the first time.

VHF and up packet&TNCs still typically operate at 1200 baud in the US, though 9600 baud is common elsewhere, and much higher rates are possible on good links upwards of UHF.

universal (idea)

1999-11-13T14:39:32Z

Of worldwide scope, general, ecumenical. A frown is universal body language that means among other things dislike or disapproval.

Also, a joint that connects two rotating shafts that allows free movement in all directions.