CPU280 3.5" 1760K format support

HxC Floppy emulator support for all others computers...
Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

Thanks. The .raw and the .HFE files appear to be perfectly fine.

for the format you may need a faster sdcard.

sijnstra
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Re: CPU280 3.5" 1760K format support

Post by sijnstra »

Thanks Jeff!

Speed of the card is rated up to 48MB/s read, and based on what I can find is rated up to 16MB/s sequential write (no official information available, only tested specs).

What kind of speed would avoid these issues so I can try something more likey?

Thanks,
Shawn

Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

Which sdcard model have you ?

sijnstra
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Re: CPU280 3.5" 1760K format support

Post by sijnstra »

Hi

It's a Toshiba 16GB SDHC UHS-I speed class 1, rated at 48MB/s read.

I put it through media tester (Quick Test), and the read speed, write speed and capacity were all correct with no read or write errors so unlikely fake.

Averge write speed: 13,730,673 Bytes/sec
Averge read speed: 44,351,194 Bytes/sec

Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

class 1 ?

sijnstra
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Re: CPU280 3.5" 1760K format support

Post by sijnstra »

As in UHS-1:

"UHS-1" or more accurately "UHS-I" stands for "Ultra High Speed" - 1 and is a speed class for SDHC and SXDC memory cards.

UHS-I has a bus interface speed of up to 104 MB/s.

Thanks,
Shawn

Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

sijnstra wrote:
Tue Oct 13, 2020 12:40 pm
As in UHS-1:

"UHS-1" or more accurately "UHS-I" stands for "Ultra High Speed" - 1 and is a speed class for SDHC and SXDC memory cards.

UHS-I has a bus interface speed of up to 104 MB/s.

Thanks,
Shawn
ok. Unfortunately these speed are only possible with a big write buffer. The emulator is only writing some few KB once.
Smaller/older sdcard are probably better with small writes. The 16GB Class 10 Sandisk Extreme series are quite good for example.

sijnstra
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Re: CPU280 3.5" 1760K format support

Post by sijnstra »

Interesting! So the SD Card may be too fast? I'll shop around and see what I can find. Thank you!

Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

sijnstra wrote:
Wed Oct 14, 2020 10:44 am
Interesting! So the SD Card may be too fast? I'll shop around and see what I can find. Thank you!
This more complex than this : Technically the sdcard should have a good cache algorithm :)
The issue is the small write latency. The floppy doesn't have write latency, a flash memory have a latency. The SDCard generally have the necessary cache algorithm to reduce it. But this is now done for big files (pictures/movies), not for just some sectors.

Jeff
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Re: CPU280 3.5" 1760K format support

Post by Jeff »

To illustrate this :
W7Rzk.jpg
W7Rzk.jpg (95.3 KiB) Viewed 612 times

sijnstra
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Re: CPU280 3.5" 1760K format support

Post by sijnstra »

Perfect! Thank you. Interesting to know how much variance there is between cards. I bought a Class 4 (much slower) SanDisk (changed brands as well), and now I can perfectly format as well. I will experiment with other SD cards to see what works best.

I very much appreciate your time and patience.

agl
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Re: CPU280 3.5" 1760K format support

Post by agl »

Hello Sijnstra,

I have also a CPU280 with the HGT. Tilmann Reh, the creator of the CPU280, said to me that you have a lot comunication with him in the past.
I also want to use the "SD HxC Floppy Emulator" with the "CPU280" and this thread is very usefull for me.

If you want then send an email to me over this board.

Best Regards
agl

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