[Coco] 1 or 2 meg upgrade

[William Astle]

Back in "the day", I regularly overflowed 512K in OS9. Not only does it 
allow you to run more processes simultaneously, it allows you to have a 
lot more stuff memory resident, which is nice if you're swapping disks 
all the time.

On 14-11-21 09:51 PM, Aaron Wolfe wrote:
> I am surprised you can actually allocate more than 512k under OS9.  I've
> never had much luck with that.  There is so little room in the system page
> (which doesn't get bigger when you add ram) that I always run out of room
> there before running out of free pages on a 512k coco.
>   On Nov 21, 2014 11:42 PM, "Bill Pierce via Coco" <coco at maltedmedia.com>
> wrote:
>
>>
>> Aaron, graphic screens, get/put buffers, fonts, pointers,
>> patterns,ramdisks, windows, all live "out" of the 64k workspace and out of
>> the 64k system space. Not to mention more processes can be run
>> simultainiously, who needs more than 521k? Anyone using os9, that's who.
>> What you're not realizing (or thinking about), is that the system will
>> automatically use the ram if it's there.
>> When I had a 512k machine, I was always having to be carefull of how many
>> text editors I opened, or if I had enough ram to run a graphics program
>> with all I had running at the moment. With my 1 meg Coco 3, and the Vcc set
>> at 2 meg, I do not even think about it. I just do it.
>> Who needs more than 512k?, that reminds me of Bill Gates saying no one
>> would ever need more than 64k of memory.
>>
>>
>> Bill Pierce
>> "Today is a good day... I woke up" - Ritchie Havens
>>
>>
>> My Music from the Tandy/Radio Shack Color Computer 2 & 3
>> https://sites.google.com/site/dabarnstudio/
>> Co-Webmaster of The TRS-80 Color Computer Archive
>> http://www.colorcomputerarchive.com/
>> Co-Contributor, Co-Editor for CocoPedia
>> http://www.cocopedia.com/wiki/index.php/Main_Page
>> E-Mail: ooogalapasooo at aol.com
>>
>>
>>
>>
>> -----Original Message-----
>> From: Aaron Wolfe <aawolfe at gmail.com>
>> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
>> Sent: Fri, Nov 21, 2014 10:55 pm
>> Subject: Re: [Coco] 1 or 2 meg upgrade
>>
>>
>> On Fri, Nov 21, 2014 at 10:27 PM, Gene Heskett <gheskett at wdtv.com> wrote:
>>> On Friday 21 November 2014 15:43:31 Nick Marentes did opine
>>> And Gene did reply:
>>>> On 22/11/2014 6:35 AM, Josh Harper via Coco wrote:
>>>>>    hi guys
>>>>>
>>>>> I was just wondering how hard it would be to copy the 1 or 2 meg
>>>>> memory upgrade boards from disto   as id love to have one of these
>>>>> myself thanks
>>>>
>>>> Would be nice to see Cloud9 release a 1/2Mb version of the triad.
>>>>
>>>> Nick
>>>
>>> The Triad is a 1/2 meg board, easy.  But to go to 2 megs you'll need to
>>> design a circuit that will add 2 more addressing lines to drive the
>> memory
>>> mapping of the additional memory in 8k blocks.  One could carry that to
>>> its logical conclusion at 8 megs, which has been done but while it was
>>> described in the Rainbow, was not to my knowledge ever a commercially
>>> offered product.  One of the disto complexities was also the widening of
>>> the refresh counter, needed to deal with the square architecture of 99%
>> of
>>> the memory sticks out there.  For 8 megs, the addressing IIRC expands to
>> a
>>> full 24 bits, needing a 12 bit refresh driver, and thats 4 bits wider
>> than
>>> the coco's built in dram refresh counter.
>>>
>>
>> When evaluating whether it's worth all the effort required to extend
>> beyond 512k, one should really consider why more than 512k would be of
>> any use on a CoCo.
>> There isn't any software to actually use this extra RAM besides RAM
>> disks, and RAM disks aren't all that useful in a world where we have
>> near zero seek time mass storage like the SuperIDE or CoCoSDC
>> controllers.  OS9 could theoretically use > 512k, but in practice
>> you'll usually run out of system resources and/or things to do before
>> that happens.
>>
>> $0.02
>> -Aaron
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco
>>
>>
>>
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco
>>
>