Re: RE: Does Herc support DIAG 540?

The memory check wasn't coded to check for overflow until hardware actually
reached the limit.  So earlier versions of software can't use the full 16M
or 2048M unless patched.

On Sun, Feb 16, 2020 at 9:36 PM 'Mark L. Gaubatz' [email protected]
[hercules-390] <[email protected]> wrote:

>
>
> Peter:
>
> 2G as a definition requires the use of bit-31 to describe, causing an
> addressing overflow. Not considered a problem at the time by IBM as the
> machines of the large 31-bit addressing era required the use of the upper
> memory for HSA (Hardware Storage Area). Thus, a 2G real machine generally
> (leastwise in most shops if they could afford 2G) would only provide 2047M
> or less to the OS.
>
>
>
> Mark
>
>
>
>
>
> *From:* [email protected] <[email protected]>
> *Sent:* Sunday, February 16, 2020 6:25 PM
> *To:* [email protected]
> *Subject:* RE: [hercules-390] RE: Does Herc support DIAG 540?
>
>
> <snippet>
>
> Further progress -- Apparently VM/ESA does not like a full 2G main storage
> size. 2047M seems to work and it boots to the OPERATOR on the console.
>
> </snippet>
>
> Peter
>
> ,_._,___
>
>
> 



-- 
Mike A Schwab, Springfield IL USA
Where do Forest Rangers go to get away from it all?