5.25 floppies image profile

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: 5.25 floppies image profile

Post by mr.vince »

There is a "density line" setting under the drive menu which should, while switching between HD and DD, also change the rpm. But this does not always work, it's something the drive does or does not. Some drives can be set via jumpers. KryoFlux itself can resample the data internally and interpret 360rpm as 300rpm and vice versa. But getting this correct during readout is definitely a plus. Check if you can find a data sheet for the type of drive you are using. Maybe you can force the speed with a jumper setting.
beppe
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Re: 5.25 floppies image profile

Post by beppe »

Thanks a lot mr.vince, the drive is a Fujitsu M2553K, I found a manual (I am attaching it here), and it seems that this model just goes 360rpm (see page 14).
So do you think that if I can dump the disk with a 300rmp speed I would be able to create readable images?
At this moment, as David suggested, I can open the mfm .img files with Text edit and read something of what is inside, like letters, but with a lot of confusion inside.
Thanks a lot and sorry if my questions sound sometimes silly :oops:
Giuseppe
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beppe
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Re: 5.25 floppies image profile

Post by beppe »

I just found on one of this floppies the label "CPM/86". Is this an indication for the file system that could help?
Thanks a lot again everyone
brightcaster
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Joined: Fri Nov 08, 2013 10:48 pm

Re: 5.25 floppies image profile

Post by brightcaster »

No it doesn't look like a cpm floppy. But it could be a single floppy of a multiple floppies archive made by cpm. I remember a siemens programming device running cpm86 which had a tool to make backups that way. The floppies created with that had no directory nor could they be read/written with cpm directly. They did just hold the uncompressed files from the harddisk in a sequential order...

But the content of that cpm86 floppy may give a hint to the hardware system. Maybe you'll find another floppy named after the wordprocessor which was used.

David
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mr.vince
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Re: 5.25 floppies image profile

Post by mr.vince »

beppe wrote: Wed Feb 10, 2021 10:38 am Thanks a lot mr.vince, the drive is a Fujitsu M2553K, I found a manual (I am attaching it here), and it seems that this model just goes 360rpm (see page 14).
So do you think that if I can dump the disk with a 300rmp speed I would be able to create readable images?
Just for clarification purposes: KF can interpret data at any given rate. So if you read at 360rpm (and the exact value is saved in the stream), you can have DTC interpret it as 300rpm and vice versa. The drawback here is that drive electronics do filter the raw signal for noise. So depending on what you do it might be even though KF can resample internally, the analogue circuitry might mess with the signal hence filtering out information that'd be needed. Therefore it can make a huge difference depending on the drive type (make/model) used.
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