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	<id>https://wiki.vmssoftware.com/index.php?action=history&amp;feed=atom&amp;title=ACP_DATACHECK</id>
	<title>ACP DATACHECK - Revision history</title>
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	<updated>2026-04-29T23:37:15Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
	<generator>MediaWiki 1.43.3</generator>
	<entry>
		<id>https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=2481&amp;oldid=prev</id>
		<title>Martin: /* How to set bits 5 and 6 */ Add cat</title>
		<link rel="alternate" type="text/html" href="https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=2481&amp;oldid=prev"/>
		<updated>2022-03-23T11:20:17Z</updated>

		<summary type="html">&lt;p&gt;&lt;span class=&quot;autocomment&quot;&gt;How to set bits 5 and 6: &lt;/span&gt; Add cat&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 11:20, 23 March 2022&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l36&quot;&gt;Line 36:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 36:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;| The block is a valid directory block and contains valid entries in correct alphanumeric order (reads and writes) || 3 || 1 || 1&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;| The block is a valid directory block and contains valid entries in correct alphanumeric order (reads and writes) || 3 || 1 || 1&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;|}&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-side-deleted&quot;&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-side-deleted&quot;&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;[[Category:System Parameters]]&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Martin</name></author>
	</entry>
	<entry>
		<id>https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=1872&amp;oldid=prev</id>
		<title>Jane.doe at 19:19, 13 December 2019</title>
		<link rel="alternate" type="text/html" href="https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=1872&amp;oldid=prev"/>
		<updated>2019-12-13T19:19:19Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 19:19, 13 December 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l1&quot;&gt;Line 1:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-side-deleted&quot;&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;{{SystemParameterInfobox|[[ACP_DATACHECK]]|ACP|DYNAMIC}}&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-side-deleted&quot;&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;&lt;/ins&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;#039;&amp;#039;&amp;#039;ACP_CHECK&amp;#039;&amp;#039;&amp;#039; is a bitmask [[System Parameters|system parameter]] that controls the consistency of checks performed on internal file system metadata such as [[File header|file headers]].&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&amp;#039;&amp;#039;&amp;#039;ACP_CHECK&amp;#039;&amp;#039;&amp;#039; is a bitmask [[System Parameters|system parameter]] that controls the consistency of checks performed on internal file system metadata such as [[File header|file headers]].&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Jane.doe</name></author>
	</entry>
	<entry>
		<id>https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=1008&amp;oldid=prev</id>
		<title>Darya.zelenina at 09:17, 2 July 2019</title>
		<link rel="alternate" type="text/html" href="https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=1008&amp;oldid=prev"/>
		<updated>2019-07-02T09:17:37Z</updated>

		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;table style=&quot;background-color: #fff; color: #202122;&quot; data-mw=&quot;interface&quot;&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
				&lt;col class=&quot;diff-content&quot; /&gt;
				&lt;col class=&quot;diff-marker&quot; /&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #202122; text-align: center;&quot;&gt;Revision as of 09:17, 2 July 2019&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l1&quot;&gt;Line 1:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;−&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;ACP_CHECK&#039;&#039;&#039; is a bitmask [[System &lt;del style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;parameters&lt;/del&gt;|system parameter]] that controls the consistency of checks performed on internal file system metadata such as [[File header|file headers]].&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot; data-marker=&quot;+&quot;&gt;&lt;/td&gt;&lt;td style=&quot;color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;&#039;&#039;&#039;ACP_CHECK&#039;&#039;&#039; is a bitmask [[System &lt;ins style=&quot;font-weight: bold; text-decoration: none;&quot;&gt;Parameters&lt;/ins&gt;|system parameter]] that controls the consistency of checks performed on internal file system metadata such as [[File header|file headers]].&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;br&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{| class=&amp;quot;wikitable&amp;quot;&lt;/div&gt;&lt;/td&gt;&lt;td class=&quot;diff-marker&quot;&gt;&lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;{| class=&amp;quot;wikitable&amp;quot;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Darya.zelenina</name></author>
	</entry>
	<entry>
		<id>https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=50&amp;oldid=prev</id>
		<title>Darya.zelenina: Created page with &quot;&#039;&#039;&#039;ACP_CHECK&#039;&#039;&#039; is a bitmask system parameter that controls the consistency of checks performed on internal file system metadata such as File header|fi...&quot;</title>
		<link rel="alternate" type="text/html" href="https://wiki.vmssoftware.com/index.php?title=ACP_DATACHECK&amp;diff=50&amp;oldid=prev"/>
		<updated>2018-08-23T04:06:34Z</updated>

		<summary type="html">&lt;p&gt;Created page with &amp;quot;&amp;#039;&amp;#039;&amp;#039;ACP_CHECK&amp;#039;&amp;#039;&amp;#039; is a bitmask &lt;a href=&quot;/index.php?title=System_parameters&amp;amp;action=edit&amp;amp;redlink=1&quot; class=&quot;new&quot; title=&quot;System parameters (page does not exist)&quot;&gt;system parameter&lt;/a&gt; that controls the consistency of checks performed on internal file system metadata such as File header|fi...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;&amp;#039;&amp;#039;&amp;#039;ACP_CHECK&amp;#039;&amp;#039;&amp;#039; is a bitmask [[System parameters|system parameter]] that controls the consistency of checks performed on internal file system metadata such as [[File header|file headers]].&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! Bit !! Description&lt;br /&gt;
|-&lt;br /&gt;
| 0 || Set this bit to perform consistency checks on read operations. When this bit is set, the IO$M_DATACHECK function modifier is automatically set on all subsequent IO$_READLBLK operations that read file system metadata (see the HP OpenVMS I/O User&amp;#039;s Reference Manual).&lt;br /&gt;
|-&lt;br /&gt;
| 1 || Set this bit to perform consistency checks on write operations. When this bit is set, the IO$M_DATACHECK function modifier is automatically set on all subsequent IO$_WRITELBLK operations that read file system metadata (see the HP OpenVMS I/O User&amp;#039;s Reference Manual). &lt;br /&gt;
|-&lt;br /&gt;
| 2 || Set this bit to perform read-after-write consistency checks. This is similar to setting bit 1, except that in this case the file system does the checks, not the lower level device or disk driver. Note that read-after-write consistency checks are not allowed on deferred writes. Deferred writes are turned off if this bit is set.&lt;br /&gt;
|-&lt;br /&gt;
| 3 || Reserved for VSI use only; must be zero. &lt;br /&gt;
|-&lt;br /&gt;
| 4 || Reserved for VSI use only; must be zero.&lt;br /&gt;
|-&lt;br /&gt;
| 5,6 || see [[ACP_DATACHECK#How to set bits 5 and 6|How to set bits 5 and 6]] below&lt;br /&gt;
|-&lt;br /&gt;
| 7 || Reserved for VSI use only; must be zero.&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=How to set bits 5 and 6=&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
|-&lt;br /&gt;
! To check that... !! Select this level !! Set bit 6 to !! Set bit 5 to&lt;br /&gt;
|-&lt;br /&gt;
| The block is a valid directory block (reads only)  || 0 || 0 || 0&lt;br /&gt;
|-&lt;br /&gt;
| The block is a valid directory block (reads and writes) || 1 || 0 || 1&lt;br /&gt;
|-&lt;br /&gt;
| The block is a valid directory block and contains valid entries (reads and writes) || 2 || 1 || 0&lt;br /&gt;
|-&lt;br /&gt;
| The block is a valid directory block and contains valid entries in correct alphanumeric order (reads and writes) || 3 || 1 || 1&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Darya.zelenina</name></author>
	</entry>
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