On Thu, 2 Oct 2008 11:16:53 -0500, Hal Merritt <[EMAIL PROTECTED]> wrote:
>We are looking to deploy a number of 'information only' consoles using >PC's and suitable TN3270 client software and the ICC. Of course, PC's >fail and just disappear. With full function consoles on a 2074 or Visara >controller, this can cause console buffer shortages. > >From a console buffer point of view there is no difference between a full- function console and one that is information-only. One may have more messages queued to it than the other but the point is any kind of console uses console message buffers of some sort. That being said, there are differences in the buffering that is done for MCS/SMCS consoles and EMCS consoles. MCS and SMCS consoles all use the same buffer pool. This buffer pool was designed back when memory was really small and really expensive, so only a single copy of a message exists in the pool -- but it is queued (in- directly) to every console that it is to be displayed on. As each console displays the message, the message in the buffer is unqueued from that console. But -- and this is why we have gotten buffer shortages -- the message is not deleted from the buffer pool (and the buffer space reused) until the last console displays the message. If a console fails to display the message becauses its hung or otherwise unresponsive (and we can't tell that its really dead), the message will stay in the buffer pool until some overt action (such as K Q) removes it. So its a good idea to make sure that your consoles remain healthy or that you have some automation to deal with a buffer shortage by shooting the appropriate console so that we know that its dead. EMCS consoles on the other hand do not use the same buffer pool as MCS/SMCS consoles. EMCS consoles each have their own copy of a message in a data space. For TSO Operators, the data space is unique to the TSO user. For address spaces such as NetView (which uses EMCS consoles for automation purposes), multiple EMCS consoles in the address space will use the same data space although each will have their own copy of a message. So the answer to your question is that it depends on whether your information-only console is a standard MCS or SMCS console or something supported off of an EMCS console. My guess is that you were planning to just define another MCS or SMCS console, so yes console buffers are still a consideration. And yes we're aware that they are still a problem (though less so after the Console Restructure). W. Kevin Kelley IBM POK Lab -- z/OS Core Technical Development ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
