Channel - Revision history

Jnc: rm duplicate content (now in 'IBM I/O channel')

2024-04-09T15:18:35Z

rm duplicate content (now in 'IBM I/O channel')

← Older revision		Revision as of 15:18, 9 April 2024
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	They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.		They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.

	The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although ~~they~~ are implemented with shared hardware).		The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although the individual PPU's are implemented with one set of shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.

	The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.

	For the channels which include a specialized control unit, not a full general-purpose CPU, the individual operations are called '''channel command words'''; they are generally stored in main memory, and are organized into '''channel programs'''.		For the channels which include a specialized control unit, not a full general-purpose CPU, the individual operations are called '''channel command words'''; they are generally stored in main memory, and are organized into '''channel programs'''.

	IBM channels come in two varieties: a '''multiplexer channel''' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a '''selector channel''' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

	Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.		Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

Jnc: /* See also */ +IBM I/O channel

2024-04-09T12:37:41Z

Jnc: +cat

2018-12-15T14:27:25Z

+cat

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			[[Category: Hardware Basics]]

Jnc: mention connections

2018-11-08T13:54:07Z

mention connections

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	A '''channel''' is a block of [[hardware]] (effectively a [[co-processor]]) which performs [[input/output\|I/O]] operations, off-loading that work from the main [[Central Processing Unit\|CPU]]; they usually have direct access to [[main memory]].		A '''channel''' is a block of [[hardware]] (effectively a [[co-processor]]) which performs [[input/output\|I/O]] operations, off-loading that work from the main [[Central Processing Unit\|CPU]]; they are connected to [[peripheral]]s, and usually have direct access to [[main memory]].

	They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.		They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.
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	The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.		The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.

	For the channels which include a specialized control unit, not a full general-purpose CPU, the individual operations are called '''channel command words'''; they are generally stored in main memory, and are organized into a '''channel ~~program~~'''.		For the channels which include a specialized control unit, not a full general-purpose CPU, the individual operations are called '''channel command words'''; they are generally stored in main memory, and are organized into '''channel programs'''.

	IBM channels come in two varieties: a '''multiplexer channel''' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a '''selector channel''' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.		IBM channels come in two varieties: a '''multiplexer channel''' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a '''selector channel''' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

Jnc: Add control words/program

2018-11-08T13:42:12Z

Add control words/program

← Older revision		Revision as of 13:42, 8 November 2018
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	They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.		They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.

	The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.		The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware).

	IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.		The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.

			For the channels which include a specialized control unit, not a full general-purpose CPU, the individual operations are called '''channel command words'''; they are generally stored in main memory, and are organized into a '''channel program'''.

			IBM channels come in two varieties: a '''multiplexer channel''' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a '''selector channel''' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

	Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.		Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

	==See also==		==See also==

	* [[DF10 Data Channel]]		* [[DF10 Data Channel]]

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Jnc: +See also

2018-11-07T18:50:57Z

+See also

← Older revision		Revision as of 18:50, 7 November 2018
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	Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.		Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

			==See also==
			* [[DF10 Data Channel]]

	{{semi-stub}}		{{semi-stub}}

Jnc: typo

2018-11-07T18:38:50Z

typo

← Older revision		Revision as of 18:38, 7 November 2018
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	They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.		They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.

	The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[~~Conditional~~ branch]]ing capability.		The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[conditional branch]]ing capability.

	IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.		IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

Jnc: Mention cond branch

2018-11-07T18:38:27Z

Mention cond branch

← Older revision		Revision as of 18:38, 7 November 2018
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	They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.		They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access\|DMA]] from [[device controller]]s do a lot of what a channel does.

	The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s.		The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines\|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s, with [[Conditional branch]]ing capability.

	IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.		IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

	~~They~~ were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.		Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

	{{semi-stub}}		{{semi-stub}}

Jnc: A pretty good start

2018-11-07T14:18:32Z

A pretty good start

New page

A '''channel''' is a block of [[hardware]] (effectively a [[co-processor]]) which performs [[input/output|I/O]] operations, off-loading that work from the main [[Central Processing Unit|CPU]]; they usually have direct access to [[main memory]].

They are most commonly found on [[mainframe]] systems; on smaller machines, mechanisms such as [[Direct Memory Access|DMA]] from [[device controller]]s do a lot of what a channel does.

The details vary considerably from manufacturer to manufacturer: for instance, the Peripheral Processing Units of the [[CDC 6600]] are effectively channels, but they are essentially complete [[minicomputer]]s (although they are implemented with shared hardware). The channels of [[International Business Machines|IBM]] mainframes are programmable, but are much more limited in functionality; they are [[finite state machine]]s.

IBM channels come in two varieties: a 'multiplexer channel' handles a group of slow-speed devices, and interleaves operations to each of them, with each transfer handling single small data item (e.g. a [[byte]]); a 'selector channel' handles high-speed devices such as [[disk]]s and [[magnetic tape drive]]s, and transfers an entire block at a time.

They were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

{{semi-stub}}

← Older revision		Revision as of 12:37, 9 April 2024
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	Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.		Channels were apparently first introduced with the [[IBM 709]], and other manufacturers copied the idea.

			{{semi-stub}}

	==See also==		==See also==

			* [[IBM I/O channel‎]] - the most common form
	* [[DF10 Data Channel]]		* [[DF10 Data Channel]]

	~~{{semi-stub}}~~

	[[Category: Hardware Basics]]		[[Category: Hardware Basics]]