> On 2018-05-25, at 17:03, Mia Magnusson <mia@plea.se> wrote: > >>> You will not gain anything by using the various "DMA" modes on an >>> IDE/CF disk with a 1MHz 6502 system as the disk is faster than the >>> computer even in the disks slowest mode. >> >> You would gain quite a bit. A 6502 copy loop will take something like >> 14 cycles per byte to copy, while using DMA you should be able to >> average 1 cycle per byte. > > DMA here refers to various bus modes for data transfer to/from the > disk, not actual DMA in the host system. But this is what smf wrote, isn't it? And those modes are meant to to be used with DMA in the host system. At least AFAIR from about two decades ago. If you can use the DMA mode you should be able to move data much faster than with PIO, _especially_ on a slow CPU like the 6502@1MHz. It is not about the disk being slow in the PIO mode. It is about the CPU being slow to move the data around in PIO mode. -- SD! - http://e4aws.silverdr.com/Received on 2018-05-25 18:02:08
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