4.23MB DSDD Atart FAT12 image

HxC Floppy Emulator on Atari ST support
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AdamK
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4.23MB DSDD Atart FAT12 image

Post by AdamK »

How do they work? I was able tocreate them, but I couldn't read them on ST (TOS 1.06), on Falcon I could read directory but not the file on image.

Jeff
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Re: 4.23MB DSDD Atart FAT12 image

Post by Jeff »

AdamK wrote:How do they work? I was able tocreate them, but I couldn't read them on ST (TOS 1.06), on Falcon I could read directory but not the file on image.
Falcon xbios functions doesn't support floppy with more than 80 tracks.

rpineau
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Re: 4.23MB DSDD Atart FAT12 image

Post by rpineau »

This is not totally true as we can format floppy with 82 tracks, 20 sector per track with Fastcopy pro and they work fine.
The track register of the WD1772 is a 8 bit register and will accept track from 0 to 240, the limit of 80 tracks (82) is mostly a physical limit on the floppy drives. Same for the sectors.
Here is what the datasheet of the wd1772 says :

"The number of sectors per track for the WD1772 range from 1 to 240. The number of tracks for the WD1772 range from 0 to 240."
it's page 8/20 in this document : http://info-coach.fr/atari/documents/my ... LG-V11.pdf

The Falcon xbios function to format floppies also accept more than 80 tracks and 18 sectors for HD format (tested). The GEM dialog to format floppies is what limits the formatting to 80/18

Regards, Rodolphe

Zozosoft
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Re: 4.23MB DSDD Atart FAT12 image

Post by Zozosoft »

rpineau wrote: The track register of the WD1772 is a 8 bit register and will accept track from 0 to 240
The datasheet say this but it is not fully true! The 240 limit only valid if the WD1772 used to format the disk. Because at the Write Track command some values in the track data bytes used as control codes, write CRC, header, etc These values can not used elsewhere, for example as track or sector number. Then you can not format disk with more than 240 track with WD1772. But if other controller (at the current situation the HxC) do the formating then at the sector read/write operations can use track numbers up to 255!
When the HxC manager running on the host computer and use HxC Direct Access Mode, then the communication use sector read/write at the track 255.

On Enterprise 128 which are also use WD1772 I successfully using 254 track images, up to 28 sectors.

Jeff
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Re: 4.23MB DSDD Atart FAT12 image

Post by Jeff »

rpineau wrote:This is not totally true as we can format floppy with 82 tracks, 20 sector per track with Fastcopy pro and they work fine.
Believe me when i said that the TOS 2.XX limit the possible track to something <=82 tracks.
This is why we had to use custom low level functions to access the track 255 for the file selector software.
The xbios call worked well with tos 1.00 <> 1.62 but doesn't with the TOS 2.XX...

Fastcopy pro probably use some custom functions to access the FDC.

rpineau
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Re: 4.23MB DSDD Atart FAT12 image

Post by rpineau »

Yes Fastcopy Pro has its own routines to talk to the FDC.
I didn't know about the TOS 2.xx issue.
I wonder if the TOS 4.0x has similar issues.

Jeff
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Re: 4.23MB DSDD Atart FAT12 image

Post by Jeff »

rpineau wrote: I wonder if the TOS 4.0x has similar issues.
For sure this is the same.

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