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New tool : DgnBlock!

Posted: Mon Nov 23, 2015 9:58 am
by robcfg
Yes friends, the mad programmer strikes back! :mrgreen:

This time, I've made a tool that lets you compare two cas files, copy blocks between them and even change the contents of a block. It's specially useful when you've got two dumps with errors as it will make it easy to get a full working cas file.

It works on Windows, Mac and Linux platforms, and most probably on several more...

You can find the source code, prebuilt Windows binaries and screenshots at the project's BitBucket repository.

As usual, if you find any error, have any doubt or just want to leave some feedback, post in this thread and I'll take a look as soon as I can.


Re: New tool : DgnBlock!

Posted: Mon Nov 23, 2015 10:05 pm
by sorchard
That looks great Rob! Thanks again for sharing.

It does kind of overlap with an idea of my own, though I've been attacking the problem from a different direction. I thought along similar lines that it would be nice to be able to feed in say 10 different captures and have the tool automagically pick out the best blocks to string together a reconstruction.

The approach I've been playing with is generating a histogram of the cycle lengths and then using information from this to decode each block. I've found, with my creaky old tape deck at least, that the histogram varies enough from block to block to warrant evaluating a new histogram for each block. It might even be worth working from a sliding histo centred on the current read position but I haven't tried this yet.

The histogram approach also works well for autodetecting the signal phase. When reading in the correct phase, you get a nice bimodal distribution with a significantly bigger variance compared to reading in the wrong phase.

I'll report back when I have something that is easy to experiment with. (And when my day job actually lets me have some time!)

Re: New tool : DgnBlock!

Posted: Mon Nov 23, 2015 10:22 pm
by robcfg
Hi Stew!

You certainly could do what you suggest with my tool but in a non automatic way.

My tool would also show if two blocks with a valid crc have different contents (via the compare button).

In the end you'll have to take a look by yourself to check that everything matches. Also, sometimes you'll find blocks with invalid crc that are supposed to be that way, for example on Buzzard Bait.

Anyway, if there's any feature you'll find useful, I can take a look and include it in my program.


Re: New tool : DgnBlock!

Posted: Tue Dec 08, 2015 7:15 am
by dragonmarce
Great work Rob!