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GeneralRe: Goats like it when you smile at them Pin
Sander Rossel14-May-21 7:19
professionalSander Rossel14-May-21 7:19 
GeneralRe: Goats like it when you smile at them Pin
jeron114-May-21 10:33
jeron114-May-21 10:33 
GeneralRe: Goats like it when you smile at them Pin
PIEBALDconsult14-May-21 6:21
mvePIEBALDconsult14-May-21 6:21 
JokeRe: Goats like it when you smile at them Pin
Vivi Chellappa15-May-21 0:55
professionalVivi Chellappa15-May-21 0:55 
GeneralRe: Goats like it when you smile at them Pin
Roger Wright15-May-21 17:02
professionalRoger Wright15-May-21 17:02 
GeneralWSO CCC OTD 2021-05-14 Solution: Pin
OriginalGriff14-May-21 1:31
mveOriginalGriff14-May-21 1:31 
GeneralRe: WSO CCC OTD 2021-05-14 Solution: Pin
pkfox14-May-21 1:46
professionalpkfox14-May-21 1:46 
GeneralRemember the C64's lightning fast floppy drives? Pin
CodeWraith13-May-21 23:43
CodeWraith13-May-21 23:43 
300 bytes/s, what a slowpoke. Even Atari's 1050 disk drive was better. With 19200 kb/s you at least got something between 1024 bytes/s and 2048 bytes/s. In both cases the serial connection was the bottleneck. Cheap, but not very fast. But why should it be? Those computers never had more than 64k memory to fill.

Fast forward to today. While the idea of having something like a single board computer to control the drive, manage the file system and data transfer from and to the main computer is still ok, we might get access to slightly more data and need better transfer rates.

Mechanical drives are out. Why not use a Compact Flash card as a SSD? Accessing it is extremely simple. You just have to map its 8 registers as I/O ports and you get access to gigabytes of storage. An 8 bit mode is also available, so there will be no waste of half of the memory space or awkward 8/16 bit conversion.

How fast will that be? At 6 MHz, my little CDP1802 processor can shovel about 37500 bytes/s and, since it's not a mechanical drive, the CF card can easily keep up with that. If the processor could fill its normal 64k in less than two seconds. Not bad for an 8 bit computer, but still slow if I want to use my unmodest 16 megabyte memory expansion.

Then there is the question, what file system I should use. Do you think that FAT32 is too much for an 8 bit computer?

And there is also still the question, what sort of connection to the main computer to use to get those bytes transferred fast enough. Serial? 200 kb/s with the old UARTs. More than 10 times faster than the old Atari floppies, bur still too slow. Parallel? We would end up at the processor's maximum again. 37500 bytes.

So that's it? Not quite. How about 250000 bytes per second plus freeing up the processor to do something better than just shoveling bytes around? The CDP1802 never stops executing instructions, not even for DMA. It just throws in an extra bus cycle with every instruction when DMA is requested. During that DMA cycle, it plays DMA controller and does the memory addressing itself. The other device just has to read or write the byte on the data bus at the right time. Maybe I can get this to work with the CF card's DMA mode and this also can be used to transfer data between two CDP1802s.

Not that the 1802 would be finished at 6 MHz. It's not even getting warm. 8 - 10 MHz are quite possible without any special effort. With using all tricks in the book (just look up how to overclock a modern processor in Wikipedia) I have heard that they can reach over 20 MHz. At that clock frequency it would reach over 833000 bytes/s in DMA mode and still be executing code. 16 bit computers that are 10 years ahead of the old CDP1802 would have a hard time to keep up.
I have lived with several Zen masters - all of them were cats.

His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.

GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CPallini14-May-21 0:26
mveCPallini14-May-21 0:26 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
OriginalGriff14-May-21 1:04
mveOriginalGriff14-May-21 1:04 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CPallini14-May-21 1:05
mveCPallini14-May-21 1:05 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
OriginalGriff14-May-21 1:25
mveOriginalGriff14-May-21 1:25 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
honey the codewitch14-May-21 2:40
mvahoney the codewitch14-May-21 2:40 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
Mycroft Holmes14-May-21 12:14
professionalMycroft Holmes14-May-21 12:14 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CPallini14-May-21 1:33
mveCPallini14-May-21 1:33 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CodeWraith14-May-21 1:45
CodeWraith14-May-21 1:45 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CPallini14-May-21 1:55
mveCPallini14-May-21 1:55 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CodeWraith14-May-21 3:04
CodeWraith14-May-21 3:04 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
jsc4214-May-21 4:12
professionaljsc4214-May-21 4:12 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
dandy7214-May-21 5:01
dandy7214-May-21 5:01 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
honey the codewitch14-May-21 2:36
mvahoney the codewitch14-May-21 2:36 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CodeWraith14-May-21 3:10
CodeWraith14-May-21 3:10 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
honey the codewitch14-May-21 4:13
mvahoney the codewitch14-May-21 4:13 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
CodeWraith14-May-21 4:35
CodeWraith14-May-21 4:35 
GeneralRe: Remember the C64's lightning fast floppy drives? Pin
honey the codewitch14-May-21 6:24
mvahoney the codewitch14-May-21 6:24 

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