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FDC Tutorial Problems

Posted: Tue Oct 13, 2009 8:55 pm
by xixpsychoxix
I am mostly using VirtualPC to test my OS, but today i used an old Packard Bell w/ a Pentium 75 mhz processor in it to test the FDC tutorial. For some reason it will not read the sectors. I have the strange feeling that this is due to the fact that the old machine has no dma controller on it, but i am unsure. also when i try to read sector 0 on virtualpc i think that it is not working properly because the boot signature is not at the end of the sector. I think i am doing everything correctly. when i started the series i copied the code by hand, but lately i am just copying and pasting the file contents to avoid errors so i dont understand why this is not working. Also, are there any plans currently to add a section on programming the controller w/out DMA? I want to add an option to not use the controller in case of old hardware but Im not sure how to handle that.

Re: FDC Tutorial Problems

Posted: Wed Oct 14, 2009 5:28 am
by Mike

If the PC does not include a DMA, the code will, of course, not function. I was originally targeting the chapter without using the DMA, however do to most emulators and virtual machines not supporting this, I opted to go with using DMA.

It is, however, possible to update the tutorial to not use DMA by configuring the FDC in Non-DMA mode and removing the DMA code.