Empty/corrupt contents with IBM PC disk images?

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phreakindee
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Joined: Sat Jan 07, 2012 2:42 am

Empty/corrupt contents with IBM PC disk images?

Post by phreakindee »

I just got a Kryoflux and am having issues with some of my disks, and I'm not really sure what the culprit is. Not really read errors, at least it's not showing there are any problems reading. These are disks with no copy protection schemes.

I have a set of 360k floppies for my Sound Blaster 1.5 card, and one of them reads to an image fine. The other one seems to read, but all the file contents end up blank. E.G., the readme text file on the disk has the right file size, but the contents are blank. Same with batch files and everything on the disk, it's all corrupt. I've read it to an image using default MFM settings multiple times with no difference. It reads the disk just fine with the same floppy drive in a PC, but through the Kryoflux it just gets blank files.

I'm using a 1.2MB floppy drive from an IBM AT and the Java GUI under Windows 7 x64 if this is any help. I'm using an external PSU for the floppy, as well as real USB ports. Suggestions?

I've also noticed the disk images end up with a file size of 720K regardless of their actual size. 360K disks, etc. Not sure if that's normal, but it seemed odd.

TeaRex
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Re: Empty/corrupt contents with IBM PC disk images?

Post by TeaRex »

There are some things about 5.25" PC formats that the default MFM settings don't know about, since they're so general. For example, the fact that 360K IBM PC disks have only 40 tracks. So try adding "-k 2" to the command line. Also, the fact that 1.2MB disks are supposed to spin at 360 rpm; for those, drop the -k and add "-v 360". For 160K/180K disks, you need to tell it that there is only one side; so "-g 1 -k 2"; etc.

EDIT: I see you're using the GUI. Try the command line instead, it's a bit more flexible.

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Malvineous
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Re: Empty/corrupt contents with IBM PC disk images?

Post by Malvineous »

I just ran across this same issue. I wonder whether we can get new presets added to dtc for these two widely used IBM 5.25" floppy formats, so we don't have to remember all these magic parameters?

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mr.vince
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Empty/corrupt contents with IBM PC disk images?

Post by mr.vince »

That would just bloat the app. That's what scripts are for, or something that should be defined in the GUI. I've seen competitive products with hundreds of of formats supported, just to find that 90% of them are repetitive with just varying parameters.

I wonder if we should make a sticky here that lists useful command lines, e.g. see examples in the latest manual.

phreakindee
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Re: Empty/corrupt contents with IBM PC disk images?

Post by phreakindee »

Thanks for the tips! Switching to 40 track mode seems to have fixed the issues I was having with my 360k disks. Now to try and sort out my 160 and 180k floppies, as I can't seem to get those to image properly with much consistency. Some disks seem to image just fine, some not. No read errors either. I'll mess around with some command line options...

And I second the motion that there could be a sticky for common command lines for DTC. It would really help out newbies like myself, as there are only a few examples in the manual.

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Malvineous
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Re: Empty/corrupt contents with IBM PC disk images?

Post by Malvineous »

We really need a small wiki or something - the manual's great and all, but not really convenient as a quick reference.

@mr.vince: I thought the point of the DTC -i option *was* to define every format! At least that explains why -i4 doesn't hint that it's what PCs use. Out of curiosity, what is the criteria for a format to get its own entry?

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mr.vince
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Empty/corrupt contents with IBM PC disk images?

Post by mr.vince »

Every new format means it can't be read with any of the previous ones. E.g. Generic MFM is not only used by PCs, but also the Atari ST and others. The reason is they all use the same WD 177x or compatible controller.

I agree regarding the Wiki... This is really much work to maintain. Would there be any volunteers?

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Malvineous
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Re: Empty/corrupt contents with IBM PC disk images?

Post by Malvineous »

Ah right, that explains it. Yes it would be nice to have a list of common formats and the flags to use, like what is in the manual but people can add to it as they discover things.

I do run a couple of wikis myself, I would be happy to create another instance for the KryoFlux if it would help. My hosting provider (DreamHost) isn't the fastest though, but I guess we can always move it somewhere else if it proves really popular :-)

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