[Coco] Did this really happen?

[Arthur Flexser]

Oops again!  The two addresses should be $72000 and $52000 (not $62000) for
a proper test--ghosting is to addresses $20000 apart (128K), not $10000
apart (64K).

Art

On Sun, Sep 5, 2021 at 10:31 PM Arthur Flexser <flexser at fiu.edu> wrote:

> Oops, Basic may mess with address 0, safer if you try it with $72000 and
> $62000 instead.
>
> Art
>
> On Sun, Sep 5, 2021 at 10:28 PM Arthur Flexser <flexser at fiu.edu> wrote:
>
>> A quick check for 512K is to see if values poked in "ghost" to other
>> addresses that are $10000 different.  For example,
>>
>> 10 LPOKE &H70000, 111
>> 20 LPOKE &H60000, 222
>> 30 PRINT LPEEK(&H70000), LPEEK (&H60000)
>>
>> If the values printed out by line 30 are both 222, you have 128K;  if
>> they are 111 and 222, you have 512K.
>>
>> (This is off the top of my head, somebody please correct me if I've made
>> a mistake here.  It's been quite a few years.  Try it on your 128K CoCo as
>> well as the 512K (?) one to make sure this works properly.)
>>
>> Art
>>
>> On Sun, Sep 5, 2021 at 6:16 PM M. David Johnson <mdj at bds-soft.com> wrote:
>>
>>> Before I get too excited, I'd like someone, more proficient than I, to
>>> confirm my apparent unexpected blessing.
>>>
>>> I just purchased two 128K CoCo 3's off of ebay.
>>>
>>> The first one worked fine. It said "128K Color Computer 3" on the top,
>>> but
>>> just to confirm, I took a flashlight and looked through the top slots. I
>>> read MCM41464P on one of the chips (a 64K x 4 RAM I believe, implying a
>>> total 128K x 8 memory).
>>>
>>> When the second one arrived, it also said "128K Color Computer 3" on the
>>> top. But it had something rattling around loose inside the case. When I
>>> opened it up I discovered that it had empty sockets where I expected the
>>> RAM
>>> chips to be. And the thing rattling around loose was an L-shaped board
>>> with
>>> sixteen MCM6256AP12 chips on it (each a 256K x 1 RAM I believe, implying
>>> a
>>> total of 512K x 8 memory).
>>>
>>> After I said a quick "Thank You, Lord" under my breath, I re-seated the
>>> board in the headers provided on the motherboard, and closed the CoCo
>>> back
>>> up, I plugged it in and it too worked fine.
>>>
>>> Have I judged correctly?
>>>
>>> And, could the CoCo 3 512K Memory Checker available on the CoCo Archive
>>> be
>>> used to double-confirm this?
>>>
>>> --
>>> M. David Johnson
>>> mdj at bds-soft.com
>>>
>>>
>>> --
>>> Coco mailing list
>>> Coco at maltedmedia.com
>>> https://pairlist5.pair.net/mailman/listinfo/coco
>>>
>>