Directory - Revision history

Jnc: /* Data networking systems */ More accurate

2024-05-05T02:37:10Z

Data networking systems: More accurate

← Older revision		Revision as of 02:37, 5 May 2024
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	In a data network, some means must be provided for users of the network to find the various resources provided through (which seems like ''by'', to the users) the network. One or more (many more, in very large data networks like the modern [[Internet]]) directory ''systems'' perform this function.		In a data network, some means must be provided for users of the network to find the various resources provided through (which seems like ''by'', to the users) the network. One or more (many more, in very large data networks like the modern [[Internet]]) directory ''systems'' perform this function.

	In the earliest stages - for example, on the [[ARPANET]] - a means was needed to translate between the ''names'' of hosts (which were in a form suited for use by humans), and their [[address]]es (which were suited for use by the various [[software]] elements which implemented the network's services). There, these were initially provided by files, the [[host table]]s, which contained [[mapping]]s from the human-suited names to the addresses. The host tables were updated as things changed, and periodically, updated ones were distributed to all the ~~users~~.		In the earliest stages - for example, on the [[ARPANET]] - a means was needed to translate between the ''names'' of hosts (which were in a form suited for use by humans), and their [[address]]es (which were suited for use by the various [[software]] elements which implemented the network's services). There, these were initially provided by files, the [[host table]]s, which contained [[mapping]]s from the human-suited names to the addresses. The host tables were updated as things changed, and periodically, updated ones were distributed to all the sites.

	As the network grew, this was no longer feasible; changes were happening too often, and the amount of data also grew too large. The [[Domain Name System]] was devised as a distributed [[database]], which could contain those mappings; it was, in effect, a directory of the hosts on the Internet.		As the network grew, this was no longer feasible; changes were happening too often, and the amount of data also grew too large. The [[Domain Name System]] was devised as a distributed [[database]], which could contain those mappings; it was, in effect, a directory of the hosts on the Internet.

Jnc: Cover directories in data networking systems

2024-05-01T14:19:26Z

Cover directories in data networking systems

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-A '''directory''' is an element of the organization of the data in a [[mass storage]] system, which records which [[file]]s are stored in that system, along with some information about them. They exist primarily in [[file system]]s, where they typically contain collections of related files, but they are to be found in other mass storage systems as well, such as on [[magnetic tape]]s.
+A '''directory''' is a key element of the organization of a [[mass storage]] system or (more recently) a [[data network]]ing system.
 Originally, along with the information as to which blocks were part of a file, directories contained other meta-information about the file (date last modified, etc); this approach was used in early operating systems such as [[Compatible Time-Sharing System|CTSS]] and [[TOPS-10]], as well as later ones like [[Multics]] and [[Windows]].
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 [[UNIX]] started a new approach, in which most information about a file (particularly, which blocks were used to hold it) was kept in a separate structure (called an [[inode]] in UNIX); directories (usually implemented as an abstraction on top of that file layer) only held mappings from file-names (visible to users) to inode numbers.
 [[Category: OS Basics]]
 [[Category: File Systems]]

Jnc: add to new cat

2022-10-28T14:18:39Z

add to new cat

← Older revision		Revision as of 14:18, 28 October 2022
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	[[Category: OS Basics]]		[[Category: OS Basics]]
			[[Category: File Systems]]

Jnc: clarify

2022-04-21T05:11:21Z

clarify

← Older revision		Revision as of 05:11, 21 April 2022
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	A '''directory''' is an element of the organization of the data in a [[mass storage]] system which records which [[file]]s are stored in that system, along with some information about them. They exist primarily in [[file system]]s, where they typically contain collections of related files, but they are to be found in other mass storage systems as well, such as on [[magnetic tape]]s.		A '''directory''' is an element of the organization of the data in a [[mass storage]] system, which records which [[file]]s are stored in that system, along with some information about them. They exist primarily in [[file system]]s, where they typically contain collections of related files, but they are to be found in other mass storage systems as well, such as on [[magnetic tape]]s.

	Originally, along with the information as to which blocks were part of a file, directories contained other meta-information about the file (date last modified, etc); this approach was used in early operating systems such as [[Compatible Time-Sharing System\|CTSS]] and [[TOPS-10]], as well as later ones like [[Multics]] and [[Windows]].		Originally, along with the information as to which blocks were part of a file, directories contained other meta-information about the file (date last modified, etc); this approach was used in early operating systems such as [[Compatible Time-Sharing System\|CTSS]] and [[TOPS-10]], as well as later ones like [[Multics]] and [[Windows]].

	[[UNIX]] started a new approach, in which most information about a file (particularly, which blocks were used to hold it) was kept in a separate structure (called an [[inode]] in UNIX); directories (usually implemented as an abstraction on top of ~~the previous~~ file layer) only held mappings from file-names (visible to users) to inode numbers.		[[UNIX]] started a new approach, in which most information about a file (particularly, which blocks were used to hold it) was kept in a separate structure (called an [[inode]] in UNIX); directories (usually implemented as an abstraction on top of that file layer) only held mappings from file-names (visible to users) to inode numbers.

	[[Category: OS Basics]]		[[Category: OS Basics]]

Jnc: Promote to full citizen

2022-04-20T10:02:06Z

Promote to full citizen

← Older revision		Revision as of 10:02, 20 April 2022
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	~~#Redirect~~ [[~~File~~ system]]		A '''directory''' is an element of the organization of the data in a [[mass storage]] system which records which [[file]]s are stored in that system, along with some information about them. They exist primarily in [[file system]]s, where they typically contain collections of related files, but they are to be found in other mass storage systems as well, such as on [[magnetic tape]]s.

			Originally, along with the information as to which blocks were part of a file, directories contained other meta-information about the file (date last modified, etc); this approach was used in early operating systems such as [[Compatible Time-Sharing System\|CTSS]] and [[TOPS-10]], as well as later ones like [[Multics]] and [[Windows]].

			[[UNIX]] started a new approach, in which most information about a file (particularly, which blocks were used to hold it) was kept in a separate structure (called an [[inode]] in UNIX); directories (usually implemented as an abstraction on top of the previous file layer) only held mappings from file-names (visible to users) to inode numbers.

			[[Category: OS Basics]]

Jnc: redir - covered there

2017-08-07T19:47:17Z

redir - covered there

New page

#Redirect [[File system]]