https://xinu.cs.mu.edu/index.php?action=history&feed=atom&title=Mailbox 2026-06-15T16:33:03Z Revision history for this page on the wiki MediaWiki 1.34.2 https://xinu.cs.mu.edu/index.php?title=Mailbox&diff=2677&oldid=prev 2008-06-09T22:25:10Z

<p></p> <table class="diff diff-contentalign-left" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 22:25, 9 June 2008</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1" >Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'>−</td><td style="color: #222; 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;"><div>A mailbox is a messaging queue used for interprocess communication.  Mailboxes should not to be confused with the single message capability built into the <del class="diffchange diffchange-inline">process </del>control block which uses &lt;code&gt;send&lt;/code&gt; and &lt;code&gt;receive&lt;/code&gt;.   </div></td><td class='diff-marker'>+</td><td style="color: #222; 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;"><div>A mailbox is a messaging queue used for interprocess communication.  Mailboxes should not to be confused with the single <ins class="diffchange diffchange-inline">[[</ins>message <ins class="diffchange diffchange-inline">passing]] </ins>capability built into the <ins class="diffchange diffchange-inline">thread </ins>control block which uses &lt;code&gt;send&lt;/code&gt; and &lt;code&gt;receive&lt;/code&gt;.   </div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"><div>XINU allows for a finite number of mailboxes to be created.  Each mailbox is identified by a number.  Any number of processes can send and receive messages from the mailbox, provided the processes know the correct mailbox number.   </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"><div>XINU allows for a finite number of mailboxes to be created.  Each mailbox is identified by a number.  Any number of processes can send and receive messages from the mailbox, provided the processes know the correct mailbox number.   </div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color: #222; 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;"><div>When a new mailbox is created (allocated) a maximum number of messages allowed in the queue must be specified.  Memory for the messages is allocated when the mailbox is created.  Once the mailbox message queue is full, processes that attempt to send a message must wait for space in the queue.  If the queue is empty, processes that attempt to receive a message must wait for a message to be enqueued.  A message is 4 bytes long.</div></td><td class='diff-marker'>+</td><td style="color: #222; 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;"><div>When a new mailbox is created (allocated) a maximum number of messages allowed in the queue must be specified.  Memory for the messages is allocated when the mailbox is created.  Once the mailbox message queue is full, processes that attempt to send a message must wait for space in the queue.  If the queue is empty, processes that attempt to receive a message must wait for a message to be enqueued.  A message is 4 bytes long <ins class="diffchange diffchange-inline">(&lt;code&gt;int&lt;/code&gt; type)</ins>.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"><div>When a mailbox is deleted all remaining messages in the queue are destroyed.  Processes waiting to send or receive are released from the wait state.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; 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;"><div>When a mailbox is deleted all remaining messages in the queue are destroyed.  Processes waiting to send or receive are released from the wait state.</div></td></tr> </table>

Amallen https://xinu.cs.mu.edu/index.php?title=Mailbox&diff=2031&oldid=prev 2007-08-02T18:30:07Z

<p>Explanation of mailboxes</p> <p><b>New page</b></p><div>A mailbox is a messaging queue used for interprocess communication. Mailboxes should not to be confused with the single message capability built into the process control block which uses &lt;code&gt;send&lt;/code&gt; and &lt;code&gt;receive&lt;/code&gt;. <br /> <br /> XINU allows for a finite number of mailboxes to be created. Each mailbox is identified by a number. Any number of processes can send and receive messages from the mailbox, provided the processes know the correct mailbox number. <br /> <br /> When a new mailbox is created (allocated) a maximum number of messages allowed in the queue must be specified. Memory for the messages is allocated when the mailbox is created. Once the mailbox message queue is full, processes that attempt to send a message must wait for space in the queue. If the queue is empty, processes that attempt to receive a message must wait for a message to be enqueued. A message is 4 bytes long.<br /> <br /> When a mailbox is deleted all remaining messages in the queue are destroyed. Processes waiting to send or receive are released from the wait state.</div>

Agember