Re: D64 with IDE64 and a parallel connected 1541... record beaten!?
Date: 2005-11-22 17:33:12

Zitat von MagerValp <>:

> >>>>> "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.

This still does not add up to 14 seconds of wasted time, especially if you 
consider you have the whole rest of the c64 memeory for GCR-decoding-tables to 
A harddisk ought to write 170 kilobyte in 1/10th of a second, if she's slow. 
Okay, lets add that up to ONE second, because it's a 64. Good. Still 13 seconds 
left. GCR decoding as a 13 seconds excuse? Come on dudes, never heard of fast 
GCR routines?

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