Daisy chain
From Free net encyclopedia
The elementary meaning of daisy chain is a garland created from the daisy flower, generally as a children's game. One method of creating a daisy chain is as follows: Daisies are picked and a hole is made towards the base of the stem, generally by piercing with fingernails. The stem of the next flower can be threaded through until stopped by the head of the flower. By repeating this with many daisies, it is possible to build up long chains and to form them into simple bracelets and necklaces.
Different groups of children make daisy chains in different ways; there is a popular competing method which involves in the flower heads being pressed against each other, so that the final chain looks like a caterpillar.
It is likely that the technical meanings given below, associated with various pursuits, stemmed from this pursuit.
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Computer engineering
Within computer engineering. a daisy chain is a bus wiring scheme in which, for example, device A is wired to device B, device B is wired to device C, device C to device D etc. The first and last devices are normally wired to a resistor network called a terminator. All devices may receive identical signals or, in contrast to a simple bus, each device in the chain may modify one or more signals before passing them on.
Daisy chaining is a characteristic of SCSI, EIA-422 as used in LocalTalk and various industrial control networks. It should not be confused with:
- Broadcast mode networking as used in various coaxial ethernet topologies, EIA-485, and wireless systems.
- Token rings, where the data always travels in the same direction around a loop and there is no termination. Some Daisy chain-like topologies are designed internally as a token ring, the difference being whether a signal always travels to the end of the chain or not.
- DAG topologies such as USB, FireWire and modern twisted pair ethernet.
Daisy chain topologies have the advantage of simplicity in protocols, as each node only needs to know whether the information is relevant to it, or which way to forward it. The disadvantage is that each node introduces a delay in the signal, so long chains have a relatively high latency compared to broadcast topologies. A damaged or crashed node is also likely to partition the network, unlike wireless broadcast or star topologies.
Computer software
The term is also used in computer software. Daisy Chain installation is a "smart" installation, whereby an installation can happen piecemeal, as all the components of the package are connected to each other. If there is a disconnect during a web-based installation the software need not be downloaded from scratch, but rather restarted from where it stopped. Eg: the installation of Google Pack.
Electrical engineering
Within electrical engineering daisy chaining refers to placing several electrical or electronic devices in parallel by either their power connections or their data connections or both. See Series and parallel circuits.
For example, several hard drives within a single personal computer will have their data busses daisy chained with a ribbon cable to a controller on the motherboard. In addition, these same hard drives will have their power connections daisy chained not only to each other, but also to other types of peripherals that operate on the same voltage.
A simpler example is a string of light bulbs wired in parallel. Here the power to each bulb is daisy chained. Other examples would be a string of security sensors or fire alarm pull stations. These devices might only have two wires daisy chained to each, but those wires represent a low voltage data signal.
Music
In electronic music, the term daisy chain refers to a series of synthesizers, samplers, sequencers, or various other MIDI devices connected to one another in a chain via MIDI cables. Each device may receive MIDI data from devices higher up in the chain. However, long daisy chains may result in a lag between the time information is originally sent from a master device and when it is received further down the chain. This is known as MIDI delay. Because of this, many musicians prefer to use MIDI patch bays rather than creating daisy chains.
Rock climbing
In rock climbing, a daisy chain is a ladder made from nylon tape, originally made by chaining together several loops of nylon tape. It is used in aid climbing.
In free climbing daisy chain can also refer to a large nylon loop sewn together at intervals along the midlength. A climber properly attached to the daisy chain who sustains a fall will be decelerated by the breaking of the sewing at one or more places.
Incorrect attachment across a sewn section can result in hitting the deck.
Backpacking
A daisy chain in backpacking is a small strip of webbing with multiple loops, which allows the backpacker to secure many different types of objects to the exterior of the pack.
Relationships
A daisy chain also refers to any series of complicated relationships in which, over time, people have had different partners who have themselves had other partners within the same group of people.
Human sexual relations
A daisy chain refers to sexual relations between three or more people, with each person both performing and receiving oral sex simultaneously. [1]