On 2/12/06, Gerhard Adam <[EMAIL PROTECTED]> wrote: > > The common area will NOT increase dynamically in that sense. What is > being referred to is the fact that when something is added to the common > area (typically LPA), the total allocation will be rounded to the next > megabyte (segment) boundary. Therefore when the system is IPL'd, the > available amount of virtual storage to the address space will depend on > how that rounding takes place. In effect, one byte extra could cause a > 1 MB segment alignment to occur. The alignment occurs based on whether > the module added is above or below the line (PLPA or EPLPA). This is > primarily of interest for those applications that reside below the 16MB > line since any dependency there could cause constraint and therefore > prevent the application from running. Above the line there is typically > no constraint for the majority of applications, and therefore presents > no problem. > > Regards > > Adam
Adam, Ah..Maybe I'm a little bothering.Anyway,since this is the last thing I need confirmation on this topic now,I hope I'm not bothering you too much.I know,everyone's time is valuable. Can I understand what you said above like this: Yes.The expand of common area will surely 'steal' a portion of every address space's private area.In practice it usually causes little problem for application above the line. (partly because there is big enough space above the line) However,as for application below the line,sometims it does cause problems.The reason that makes difference is that the size below the line is just 16M,too small space. For example,at the beginning the common area size below the line is 5M,which leaves 11M private area below the line.Then a user executes a program which must execute below the line.If the program occupies all 11M private area,when you dynamically add modules to LPA which requres common area below the line to expand one more 1M,the system suddently faces two choices:fail the expand or abend the user's program. -- Best Regards, Johnny Luo ---------------------------------------------------------------------- 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
