BE CAREFUL - Winfellow corrupts ADFs!

[Bloodwych]

Any ADF I use with WinFellow becomes corrupted!

This doesn't happen with WinUAE.

How do I know? I do back-ups and use an excellent program called CD check that does binary comparisons of files.

After comparing the files, I found all the games loaded with WinFellow become corrupted, and have therefore been changed!

So, BE CAREFUL! I don't know if this happened with earlier WinFllow releases, but the latest one definitely causes corruption.

It may be a normal operation of the EMU to change the ADF, but I doubt it.

[Drake1009]

Hmm could you post the program on the forum?

Were you using the snapshot?

[Bloodwych]

Ok, for a start I made a small mistake - I use ADZs not ADFs since I converted all my ADFs to this format.

Secondly, I think this is a normal operation of the EMU. For some reason after I use an ADZ on Winfellow, it knocks off a kilobyte.

The ADZ continues to work ok however. So it may be the CRC checksum - what is this by the way and why are these ADZs altered under Winfellow and not WinUAE?

I've changed the title of the thread as not to cause panic if this is all that is happening - it's unfair on the authors how I phrased my post title - sorry wasn't thinking.

This EMU is great by the way. Still a little choppy on my 950 Duron with KT266A and DDR, but overall it's great for games.

Great work guys.

[Drake1009]

I never got ADZ nor DMS to work with WinUAE so I wouldn't see any difference, but I think it sounds strange that it should change the files.

BTW I have no problems with choppiness in fellow with my 533 mhz with a GeForce 1 DDR graphics adaptor (That adaptor is the most sucky one for 2d. I think my old S3Trio beat it with performance).

[Bloodwych]

I've got a Matrox G200 (don't play modern PC 3D games) that has great 2D.

The EMU runs full speed, but seems choppy. The mouse movement is jerky rather than silky smooth like on WinUAE, and the sprites seem to move in the same fashion.

A slight timing issue perhaps?

Still, I love the windowed mode with scanlines and 2x horizontal, also full screen is looking good.

Once this is finished it will rock! WinUAE, although a great EMU especially for workbench, seems to be peaks and troughs when it comes to progress. WinFellow keeps going forward.

[TikTok]

Secondly, I think this is a normal operation of the EMU. For some reason after I use an ADZ on Winfellow, it knocks off a kilobyte.

Does it only do this the first time you use the ADZ? Because if it did it every time, soon there would be no file left .

Fellow has to decompress the ADZ files to access the ADF inside (and to write to the disks); I suspect that the change in size is just because it is recompressing them again afterwards in a slightly more efficient manner (or perhaps there are other files inside your ADZ, such as Readmes etc).

A CRC is just a calculation based upon the data in a file, which produces a 16 or 32-bit number. The number is (to all intents and purposes) unique for each different file. Identical files always have identical CRCs. So by looking at CRC value, we can see if two files are the same without having to compare each individual byte of the files, so it is a lot quicker.

If your ADZ files are losing a K or two, their CRC will obviously change. However, the CRC of the adf inside should still be the same.

I've got a Matrox G200 (don't play modern PC 3D games) that has great 2D.

I have one of these too and it really is the best 2D I have seen. Shame about the 3D nowadays though .

(EDIT: bad grammar and typos)

[Bloodwych]

Thanks for the CRC explanation.

I think it only knocks 1K off once ; so your theory sounds logical about it re-writing the ADZ more efficiently.

I used some DOS program (Gzip I think) to convert my files a while ago and it may be an older version than the one integrated in the latest WinFellow.

The latest WinUAE uses the same Gzip I used however.

[Worfje]

WinFellow indeed unpacks and repacks the ADZ file to save away changes. The interior ADF stays intact and a valid zipped ADF is left (with probably another filesize).

[Bloodwych]

Thanks for clearing things up Worfje!

Keep up the good work, really appreciate what you guys do for free!