Re: D64 with IDE64 and a parallel connected 1541... record beaten!?

From: MagerValp (
Date: 2005-11-22 14:12:43

>>>>> "MM" == Marko Mäkelä <> writes:

S> - Optimised the new GCR conversion routines (about 3s gain). With
S> this version I managed to make a 35 tracks d64image in 22.6s, which
S> I believe to be a new record on the 64! Correct me if I am wrong.

AT> Never heard of "15 seconds copy"? It needs 8 secs to read a disk and 8 secs
AT> to write it, without verify. What's so great about 22 secs?

MM> I guess "without verify" also means that the GCR data will not be
MM> decoded (or checked for validity). You cannot make a sector dump
MM> ("d64image") without decoding the GCR data and interpreting the
MM> sector headers.

Also, when writing to IDE devices, there are mandatory 400 us delays
after writing to the command registers, and there's handshaking for
every byte as it's written to the command buffer. If the IDE device is
FAT formatted there are extra FAT writes every 4k or so (unless you
keep the FAT in RAM, which I doubt here). The 1541s on the other hand
can just stream bytes over the parallel cable.

Apples and oranges.

    ___          .     .  .         .       . +  .         .      o   
  _|___|_   +   .  +     .     +         .  Per Olofsson, arkadspelare
    o-o    .      .     .   o         +
     -       +            +    .

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