🚀 go-pugleaf

In article <m3y7x6j3wj.fsf@lhwlinux.garlic.com>,
Anne & Lynn Wheeler  <lynn@garlic.com> wrote:

[ snip ]

>SVS evolved into MVS ... there was a separate address space for every
>application. However, because of the heavy pointer passing paradigm,
>the "MVS" kernel actually occupied 8mbytes of every application
>16mbyte virtual address space. There was some additional hacks
>required. There were some number of things called subsystems that were
>part of most operational environments. They existed outside of the
>kernel (in their own virtual address space) ... but in the MVT & SVS
>worlds, other applications were in the habit of directly calling these
>subsystem functions using pointer passing paradigm ... which required
>the subsystems (which now were in separate address space) to directly
>access the calling application's parameters in the application's
>virtual address space.
>
>The initial solution was something called a "COMMON" segment, a (again
>initially) 1mbyte area of every virtual address space where
>applications could stuff parameter values that they needed to be
>accessed by called subsystems, resident in other address spaces.  Over
>time, as customer installations added a large variety of subsystems,
>it was unusual to find the COMMON segment taking up five megabytes.
>While these were MVS systems, with a unique 16mbyte virtual address
>space for every application, the kernel image was taking 8mbytes out
>of every virtual address space, and with a five megabyte COMMON area,
>that would leave a maximum of 3mbytes for application use (out of a
>16mbyte virtual address space).

(Just now working my way through this thread; great stuff .... )

Was there an acronym/initialism for this COMMON area?  My memory of
doing junior-level systems work on MVS systems is telling me that 
there was one, but not what.   ?

[ snip ]

-- 
B. L. Massingill
ObDisclaimer:  I don't speak for my employers; they return the favor.