limitation of PIO mode

[pulsar]

Hi
I 've been working on ata driver. What are the limitations of PIO mode except the fact it takes processor's clock cycles. What is the maximum size of the disk that can be accessed in PIO mode? because i tried to read from a 40gb disk, it's reading the lower sectors efficiently but it is not reading sectors beyond certain limit, i double checked the block address and verified that it is the correct block address by hexediting the disk. it works fine when i use image file of smaller size.

[Brendan]

Hi,

Hi
I 've been working on ata driver. What are the limitations of PIO mode except the fact it takes processor's clock cycles. What is the maximum size of the disk that can be accessed in PIO mode? because i tried to read from a 40gb disk, it's reading the lower sectors efficiently but it is not reading sectors beyond certain limit, i double checked the block address and verified that it is the correct block address by hexediting the disk. it works fine when i use image file of smaller size.

There's 2 completely seperate issues here - telling the disk drive which sectors to read or write (CHS, LBA, LBA-48, ATAPI, etc) and transferring data to/from the drive (PIO and DMA modes). It sounds like you've got problems with the first part (and the transfer itself is working fine).


Cheers,

Brendan

[pulsar]

Thanks Brendan,

I figured out, since i was using an image file and original device alternatively i changed number of heads to 10 in bochs configuration file. So it wasn't reading beyond that and it doesn't report any errors.