Difference between revisions of "Mailbox"

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=See also=
 
=See also=
* [https://docs.vmssoftware.com/vsi-openvms-programming-concepts-manual-volume-i | OpenVMS Programming Concepts]
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* [https://docs.vmssoftware.com/vsi-openvms-programming-concepts-manual-volume-i OpenVMS Programming Concepts]
* [https://docs.vmssoftware.com/vsi-openvms-system-services-reference-manual-getutc-z | OpenVMS System Services Reference Manual]
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* [https://docs.vmssoftware.com/vsi-openvms-system-services-reference-manual-getutc-z OpenVMS System Services Reference Manual]
* [https://docs.vmssoftware.com/vsi-openvms-io-user-s-reference-manual | OpenVMS I/O User’s Reference Manual]
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* [https://docs.vmssoftware.com/vsi-openvms-io-user-s-reference-manual OpenVMS I/O User’s Reference Manual]
* [http://webcache.googleusercontent.com/search?q=cache:i13Y_hUOieUJ:h41379.www4.hpe.com/openvms/journal/v9/mailboxes.pdf+&cd=1&hl=ru&ct=clnk&gl=ru| OpenVMS Mailboxes: Concepts, Implementation, and Troubleshooting by Bruce Ellis for OpenVMS Technical Journal V9:]
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* [http://h41379.www4.hpe.com/openvms/journal/v9/mailboxes.pdf OpenVMS Mailboxes: Concepts, Implementation, and Troubleshooting by Bruce Ellis for OpenVMS Technical Journal V9:]

Latest revision as of 11:53, 13 February 2023

A mailbox is a pseudo device used for interprocess communication and synchronization. The device code for mailboxes is MBAn.

Mailbox characteristics

Mailboxes can store a certain amount of information to be shared between processes, signal to a process when there is information to be read by that process. There is also a queueing mechanism for when multiple messages are being written to a mailbox. Multiple channels can be assigned to a mailbox. Mailboxes can be permanent and temporary. Temporary mailboxes are deleted when all channels to the mailbox have been deassigned; permanent mailboxes must be explicitly deleted. Mailboxes can have many writers and many readers. Mailboxes have a "size" determined by the buffer quota.

Protection

Mailboxes have four kinds of access: read (R), write (W), logical I/O (L), and or physical I/O (P).

Privileges

  • TMPMBX is required to create temporary mailboxes
  • PRMMBX is required to create permanent mailboxes
  • SYSNAM or GRPNAM are required to place the logical name for the mailbox in the appropriate table

See also