RE: 1541IDE update

RE: 1541IDE update

Date: Thu, 7 May 2009 09:10:20 +0200
Message-ID: <>
Hallo allemaal,

> Next step: copying the data between the two drives.

Using BASIC I already found out that it takes me about 3 minutes to copy
a floppy to harddisk and 4.5 to write it to floppy again. The only thing
the C64 does is sending the little ML program to the 1541 and commanding
it to execute the ML. And that's all.
In case of copying a floppy to the HD the program does nothing more then
reading a sector into a buffer using the job code and copying the
contents of the buffer to the HD. From HD to floppy is done in the same
way. The BIN containing both actions is just 181 bytes.

But there are copy programs that copy complete disks in no time, using
the C64 as in-between buffer; how do they do that? 

One idea I have does need the 16 bits interface: writing the still GCR
encoded data directly to the HD. I also have enough space to write the
data of the header as well to the HD. This would speed up the proces of
writing the data back to the floppy.
Using two 256-bytes-sectors of the 8-bits interface most probably won't
work because I will loose valuable timing telling the HD what next
sector to use and thus missing bytes from the floppy as that one won't
stop revolving and sending bytes.
A disadvantage of storing GCR encoded data is that when using the HD in
direct mode, the 1541 has to decode it all the time. And that is not my
idea of a fast device.

Next idea: adding extra memory. The idea is to read a track in one go
and decode and transfer the data to the HD later. Disadvantage: extra
hardware needed. No problem for me but I want to keep things as simple
as possible for the moment.

So any ideas, info or even better, documented source code, is welcome!

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Received on 2009-05-07 09:17:19

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