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Myarc Extended Basic binaries


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1 hour ago, atrax27407 said:

Here is a dump of the Myarc XB "DSR Loader". It appears to be looking for a file 128KOS which is probably the actual Myarc XB. This thread might be of some use:  


MYXBII.bin 8 kB · 1 download

I believe it's on the disk that came with the XBII. Here is a rollup of what I got on TI99resources: MyarcXBII software,disk,etc..

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The Myarc 128/512K Eprom that comes with Myarc XB during its powerup routine, writes code into the RAM of the Myarc XB cartridge.  Two things here.  The 128K/512K "default" eprom does not write code into an XB cartridge as it requires the Myarc XB Eprom.  Secondly, the Myarc XB cartridge is just a RAM cartridge in the memory range of >6000 to >7FFF.  One can optionally use a Super EA Cartridge, or a GramKracker with write protect off to replace the Myarc XB cartridge.  Either way, you still need the Myarc XB Eprom.


When the powerup code on the Myarc XB writes code to the Ram at >6000, it is setting up a cartridge header and the subsequent loader to load the file 128KOS.  I am not sure if it is specific to DSK1.182KOS, or if i searches each DSK device.


I did one time try to create a cartridge of the 8K bank at >6000 to >7FFF to remove the dependency of a 8K ram cartridge, however that did not work.  I do not remember the details, but it may have been a result from needing to write into that memory range to utilize the banking of the memory card.





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The Myarc XBOS needs the ram space of >6000 as the myarc memory card, bank switches the whole 32k space, leaving no room for any page-switching code, so after the 128KOS file is loaded some parts stay running in the cartridge space, when the time comes for pages of 32k to switch.


At one time I worked on making an horizon ramdisk emulate a myarc memory card if you installed the 32k ram mod to it, but it was never a finished product.


it could be possible to re-write the code to use SAMS banking system, but personally, the upcoming new RXB 2024 by Rich will be a lot better and just as fast if not faster, and without the compatibility issues that Myarc XB had in running existing basic programs.

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