How to read IEEE flopies very fast?

Date: Sat, 24 Sep 2016 19:44:56 +0200
Message-ID: <>
Hallo allemaal,

The subject can be translated into: is there a (open source) speed 
copier available for the IEEE drives, like there is Starcommander 
available for the IEC drives?

If the above answer cannot be answered, please proceed reading.

So far I created by simply reading the sectors one by one by using 
the BLOCK-READ command. My PC issued the command, not a CBM! The 
received bytes were written directly into the image. 
But it takes about 20 minutes to copy one floppy. If that sounds 
bad, that is equivalent to 75 seconds for a 1541 floppy. Rather good 
for standard command, IMHO. But if there can be any speed gained, it 
should be on the drive side. But how?

First: my target is the 8250 drive only. 
- It can read both 8050 and 8250 floppies.
- I can create images of 4040 floppies using a 1541 and Star 

If the 8250 had only one CPU, like the 1541, things would be simple: 
read a byte from the floppy and output it on the bus (using a faster 
protocol). GCR is already taken care of by the hardware so one 
problem less. In fact I would just take SC and alter the source "a 

But it has two CPUs so that won't work. If you got here, the above 
question about the speed copier couldn't be answered. But that 
doesn't mean that other information or software on this subject is 
available and before inventing the wheel twice, I would welcome 

Thank you in advance!

My idea so far: The FDC CPU keeps reading sectors in a row into some 
reserved buffers. Once a buffer is full, the IEEE CPU sends the data 
to the PC. IMHO three or four buffers are enough. Plus some bytes to 
inform the IEEE CPU what sector has been loaded into a specific 
buffer. After the FDC CPU has read all sectors of a track, the next 
track is read.

Kind regards / Met vriendelijke groet, Ruud Baltissen

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Received on 2016-09-24 18:00:02

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