n is either 1 (true) or 0 (false). The default value is 0.
When ViewPastData is enabled (n = 1), you can use the $VIEW command to examine data outside of InterSystems IRIS memory area. When this parameter is not enabled, the $VIEW command throws an error.
Changing This Parameter
On the Compatibility page of the Management Portal (System Administration > Configuration > Additional Settings > Compatibility), in the ViewPastData row, click Edit. Select ViewPastData to enable this setting.
Instead of using the Management Portal, you can change ViewPastData in the Config.Miscellanous class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).