[Coco] Preserving old CoCo diskettes...
Boisy G. Pitre
boisy at tee-boy.com
Wed May 19 01:33:53 EDT 2010
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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