Virtual address - Revision history

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2025-10-27T11:58:57Z

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Jnc: Better word

2025-10-27T00:37:56Z

Better word

Jnc: Split 'physical address' into a separate page

2025-10-26T17:29:14Z

Split 'physical address' into a separate page

Jnc: +cat

2018-12-15T19:35:54Z

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2018-05-04T14:33:37Z

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2017-09-21T19:46:42Z

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Jnc: A decent start

2016-12-26T13:46:57Z

A decent start

New page

A '''virtual address''' is an address emitted by code running when code is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[CPU]], and the actual addresses of [[main memory]]) (often referred to as '''physical addresses''').

When running a [[time-sharing]] [[operating system]], the hardware provides mapping of memory addresses emitting by code belonging to a user/process, to protect both the OS itself, and other users/processes, from errors or malicious behaviour.

Originally this protection was provided by 'base and bounds registers', which allowed the entire memory of a user/process to be relocated into a contiguous block of main memory. Now, [[virtual memory]] is usually used, which provides this protection/relocation as one of its many benefits.

← Older revision		Revision as of 11:58, 27 October 2025
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−	A '''virtual address''' is an address emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter usually referred to as [[physical address]]es).	+	A '''virtual address''' is an [[address]] emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter usually referred to as [[physical address]]es).

	When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.		When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.

← Older revision		Revision as of 00:37, 27 October 2025
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−	A '''virtual address''' is an address emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter ~~often~~ referred to as [[physical address]]es).	+	A '''virtual address''' is an address emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter usually referred to as [[physical address]]es).

	When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.		When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.

← Older revision		Revision as of 17:29, 26 October 2025
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−	A '''virtual address''' is an address emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter often referred to as ~~'''~~physical ~~addresses'''~~).	+	A '''virtual address''' is an address emitted by [[object code\|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit\|CPU]], and the actual addresses of [[main memory]], the latter often referred to as [[physical address]]es).

	When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.		When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.

← Older revision		Revision as of 19:35, 15 December 2018
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	Originally this protection was provided by '[[base and bounds]] [[register]]s', which allowed the entire memory of a user/process to be relocated into a contiguous block of main memory. Now, [[virtual memory]] is usually used, which provides this protection/relocation as one of its many benefits.		Originally this protection was provided by '[[base and bounds]] [[register]]s', which allowed the entire memory of a user/process to be relocated into a contiguous block of main memory. Now, [[virtual memory]] is usually used, which provides this protection/relocation as one of its many benefits.
		+
		+	[[Category: CPU Basics]]

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-A '''virtual address''' is an address emitted by code running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit|CPU]], and the actual addresses of [[main memory]]) (often referred to as '''physical addresses''').
+A '''virtual address''' is an address emitted by [[object code|code]] running when it is not running on a 'bare machine' (i.e. the machine is not using a 1:1 correspondence between the addresses used by code running in the [[Central Processing Unit|CPU]], and the actual addresses of [[main memory]], the latter often referred to as '''physical addresses''').
-When running a [[time-sharing]] [[operating system]], the hardware provides mapping of memory addresses emitting by code belonging to a user/process, to protect both the OS itself, and other users/processes, from errors or malicious behaviour.
+When running a [[time-sharing]] [[operating system]], the [[memory management]] [[hardware]] provides mapping of memory addresses emitting by code belonging to a [[user]]/[[process]], to protect both the OS itself, and other users/processes, from errors or malicious behaviour.
-Originally this protection was provided by 'base and bounds registers', which allowed the entire memory of a user/process to be relocated into a contiguous block of main memory. Now, [[virtual memory]] is usually used, which provides this protection/relocation as one of its many benefits.
+Originally this protection was provided by '[[base and bounds]] [[register]]s', which allowed the entire memory of a user/process to be relocated into a contiguous block of main memory. Now, [[virtual memory]] is usually used, which provides this protection/relocation as one of its many benefits.