[Coco] How much memory

[L. Curtis Boyle]

I have to say... when we used the Coco at work (or even when developing NitrOS9), we regularily used >512K. If you are running multiple large programs (or with large memory spaces), and a fair number of graphics windows (which are 16 or 32K each by themselves), then you can run out of RAM pretty quick. I don't think we used >1 MB of RAM too often, but 512K we ran out of a lot until we upgraded. If I remember correctly, you can have up to 16 screens defined, with up to 32 windows (kept track of in the GRFDRV memory map), while with process descriptors you were limited to how many you could fit into system RAM with the amount of room left in the 64K system process space, which depended on the size of your bootfile,etc. For that reason, I would go with option 1 as well. Nitros9 was ideally set up for up to 2 MB of RAM that could be used for loading modules, processes, graphics, fonts, etc., and anything past that would be a RAM drive (like Paul Barton's 8 MB upgrade).
Also, if Chris Dekker's extensions to GRFDRV for doing horizontal scrolling, etc. ever got fully implemented in Nitros9, you may need more than 32K per screen as well.

Wish I had time to do development again... maybe someday.

L. Curtis Boyle
curtisboyle at sasktel.net



On Nov 27, 2010, at 2:25 PM, Frank Swygert wrote:

> I agree with Aaron. Fast memory that OS-9/Nitros-9 can use would be best. One little nit though -- BASIC can't address 512K, not without a lot of modification anyway. BASIC is still limited to 64K without bank shifting some of the RAM or using some other tricks. A RAM drive was a nice way to utilize the full 128/512K or RAM in a CC3 and speed things up at the same time. A program could then be written in a modular form and unload/load modules as needed quickly. That was one trick I used in "CoCo Family Recorder", a modular genealogy program. At least I seem to recall doing that... was a long time ago!
> 
> --------------
> Date: Fri, 26 Nov 2010 22:21:43 -0500
> From: Aaron Wolfe<aawolfe at gmail.com>
> 
> On Fri, Nov 26, 2010 at 9:48 PM, Becker, Gary<Gary.Becker at amd.com>  wrote:
> 
>> >  I was just wondering, how much memory could a CoCo3 realistically use. BASIC can only address 512K. NitrOS-9 can address a lot more, but it has a fixed amount of system resources and after they are used, any additional RAM is wasted. A RAM drive is a good way to utilize a bunch of additional RAM. Compiling C programs from a RAM drive is definately a lot faster than from a HDD. Which of these three options is better?
>> >
>> >  1 1.5 Meg of memory that is able to run at 25 MHz.
>> >
> Assuming we are talking about CoCo3FPGA, I vote for option 1.  As you
> mentioned, with OS9 it is difficult to actually consume 512k with
> processes to start with, due to limited space in the system page.
> There is OS9 L3 and/or maybe some future projects that would open up
> the system area enough to use more ram for processes.  If so, it would
> be preferable to have this ram be fast as possible.
> 
> IMHO, a ram drive just isn't much use when the CPU is 25Mhz and the
> primary storage is 460kbps..  everything is very, very quick without a
> ram drive.   I would not give up any "fast ram" that may be useful for
> processes in exchange for a ram drive.
> 
> 
> 
>> >  2 512K at 25 MHz and 8 or more Meg for a RAM Drive that can be accessed at 3.5 MHz or less.
>> >
>> >  3 Eight or more Meg of RAM that can be accessed at 3.5 MHz or less.
>> >
>> >  Please limit to these three options.
>> >
>> >  Gary
>> >
>> >
> -- 
> Frank Swygert
> Publisher, "American Motors Cars"
> Magazine (AMC)
> For all AMC enthusiasts
> http://www.amc-mag.com
> (free download available!)
> 
> 
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