[Coco] Emulator

Gene Heskett gene.heskett at verizon.net
Tue Sep 8 09:46:21 EDT 2009

On Tuesday 08 September 2009, Boisy G. Pitre wrote:
>On Sep 7, 2009, at 10:13 PM, Gene Heskett wrote:
>> It is a technique I used when I wrote myram, a ramdisk for coco3's.
>> I could
>> actually use 1.5 or 1.7 megabytes of the 2 megs in my machine as a
>> ramdisk by
>> such paging.  Coupled with an automatic initialization (formatting)
>> when
>> accessed the first time, which took about 100 milliseconds to do,
>> and a full
>> 100% removal when you were done with it, I thought it would be the
>> killer
>> ramdisk for expanded coco3's, but it hasn't caught on for some reason.
>Gene, if you want to integrate myram into the NitrOS-9 project, feel
>free to do so.  I don't have time to do it myself, but am all in favor
>of replacing the Tandy-supplied RAM disk with something more robust.
>Refresh my memory on exactly how myram is different from Tandy's
>offering.  Is it smaller in size?

Probably not, but I never found its size a hindrance.  It might be  bigger 
than rammer if that is what you are referring to  A bit over 700 bytes for 
the driver + the usual descriptor.

Tandy's offering wasn't exactly bugfree.  This one did it a lot closer to 
right, and in my use I have never lost a byte of data with it once I actually 
started to use it on a day to day basis.

>Do you need different descriptors
>for different RAM disk sizes?  I'm looking for a general set of

IIRC the size is stated in 8k pages, in the sct var of the descriptor, so I 
was able to test it by setting that to different values with dmode. If it is 
not initialized when accessed the first time, it does a minimal format of the 
first 3 or 4 sectors, taking a few milliseconds.  When done, a deiniz /r0 
returns every byte of memory it used to the free pool.  No leaks.

I don't have access to the coco3 from here ATM, linux has managed to kill 
bluetooth in recent kernels.

The src archive s/b on rtsi as myramv2.lzh.  It will need assembled, and I 
think I was using Chris Burkes csm for the 6309 stuff back then, but it can 
be built on either cpu by setting a header variable named h6309 true/false.

>Coco mailing list
>Coco at maltedmedia.com

Cheers, Gene
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