Re: CISC (ugh!) question

[John Jones <chianime@xxxxxxxxx>]

Might have been based on memory chip density & the system's number of
physical slots for memory features.

On Thu, Sep 29, 2011 at 4:27 PM, John McKee <jmmckee@xxxxxxxxxxxxxx> wrote:

>  A few weeks ago, I saw something on the list about how a modern system
> (can't recall if the system referred to was a 270 or whatever).  Just
> remember that "the doctor" described the possible memory expansion for it.
>  And that expansion was not "official" from IBM as I recall.
>
> Which brought this nagging question to mind.  There is no practical value
> to any answer - except pure unrelenting curiosity.  I worked with a B50.  It
> was purchased with 24M of RAM.  Prior to my arrival, a deal was made to swap
> the genuine IBM memory for 48M of IPL memory.  That system was loaded down
> beyond belief.
>
> I was told that 48M was the absolute maximum memory that the B50 could
> address.
>
> This was obviously way before any customer oriented maintenance on a RISC
> system.
>
> Was 48M the absolute maximum memory that the old beast could support?
>
> My assumption, based on tremendous change in nearly 20 years is that 48M
> was indeed the maximum.  But, why 48?  Not a power of 2.
>
>
> John McKee
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