Den Fri, 25 May 2018 17:43:18 +0200 skrev silverdr@wfmh.org.pl: > > > > 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. Well, DMA and PIO only refers to the x86 PIO and the 82xx DMA controller bus cycles, so with any other host system you can select whichever of IDE PIO or IDE DMA mode that suits you disregarding if you are using DMA or PIO in the host system. -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2018-05-25 19:00:08
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