Re: 'Frankenstein' Disk Drives, Done Cheap

From: smf <smf_at_null.net>
Date: Mon, 5 May 2014 20:41:09 +0100
Message-ID: <580118183C274CFC8377C7955252CD81@smf>
>You could use a slower speed for a regular accelerator, but it would not be 
>useful for what I was targeting,
> which was streaming reads of an entire track at once in order to read all 
> copy protected bits.

For PRG loading you wouldn't need to transmit the raw GCR at all, however 
you would need to decode it on the drive but jiffydos is already doing that.

I'd be surprised if burst mode couldn't be made to run as fast or faster 
than jiffydos. The cpu overhead of doing the bitbanging has to be greater 
than using the CIA, even at 1mhz. The problem is the amount of effort 
required to just speed up the C128 + 1571/1581.

I did look at what hardware/software changes would be needed to implement 
burst mode on the 1541. There is an official work round for the shift 
register bug in the VIA, plus I think the 1571 has a buffer for transmitting 
that is disabled/enabled using a bit on one of the VIA parallel port pins 
(which is why the 1571 can't use the same parallel port hook up as a 1541). 
I think that would be an awesome project that would free us from the 
shackles of jiffydos.


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Received on 2014-05-06 10:00:03

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