Sunday, February 24, 2013
Some notes on accessing track 0 on SGSBCSD
Well, I've told that C000h TPA (strictly speaking, not TPA, but start of CCP) based CP/M image starts from track 0 / sector 0, the C200h system should start from SD offset 200h - i.e. track 0 / sector 1,D000h TPA - from track 0 / sector 8 That leads to a significant problem: everything works until you do not try to rewrite/regenerate CP/M itself inside of SBC, because the changes will we written to track 0 / sector 0 which will led to unusable boot image. So, if you want to do system change inside of SBC - use C000h based systems for now. In future I plan to change the algorythm of accessing track 0. Saying we have C800h TPA system starting from sector 4 and trying to write track 0/sector 0. I will add 4 to sector number so you'll access sector 4 as expected. That will lead to the situation you will not be able to access track 0 sector 0-3 at all. I think this is not a significant loss.