[Coco] Preserving old CoCo diskettes...

[Boisy G. Pitre]

On May 19, 2010, at 12:11 AM, Darren A wrote:

> On 5/18/10, Boisy G. Pitre wrote:
>> 
>> I make this assertion based on my understanding of the design of the Drive
>> Pak vs. the SuperIDE.  As I understand it, Drive Pak uses a 6551 to talk to
>> the SD card.  If this is correct, then it means that Drive Pak's throughput
>> is ultimately bound by the speed at which the 6551 talks to the SD card,
>> which is either 115,200 or 230,400 bps.  For benefit, let's assume it is the
>> latter. This means that at a rate of 230,400 bps, the theoretical maximum
>> throughput that you can hope to achieve is:
>> 
>>       230,400 bits per second / 8  = 28,800 bytes per second
>> 
> 
> ---
> 
> Yes. It does operrate at 230,400 bits per second, but when you include
> start and stop bits there are 10 bits per byte (23,040 bytes per
> second).

Thanks for clarifying this Darren. This means that the SuperIDE/SD is 2X (47,663 Bps / 23040 Bps) faster, not 1.65X faster than Drive Pak's theoretical maximum, and in the CF case it is 2.5X (58,254 Bps / 23040 Bps) faster than Drive Pak's theoretical maximum.

> Darren
> 
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