Please avoid xDMS with files which contain headers

andreas · 28 March 2006, 10:10

I've just decided to open this thread to clear up another obscurity and most probably explain those WAGONLOADS of recent [ b]- and [ o] adfs I found out about.

Especially in Demos section, I found LOADS of ADFs which were marked either [ b] or [o] (overdump).
The reason was not that obvious, until I unpacked them on REAL amiga with REAL DMS:

DMS files may contain ascii headers. If those are unpacked using xDMS on a win32 PC, the header will be placed at the beginning of the files and make the ADF unusable because the boot block data will be shifted!

That is, viewed with a hex editor in ascii mode, the resulting ADF will be something like

Code:

...Game..XYZ...trained...by...Dummbeutel...of...Nixkoenners....DOS....Nup...dos.library ....

To make this disk bootable again, you must strip off the header. Rule of thumb: from byte 0 to one byte before the 'DOS'
And believe it or not: in most cases when doing this, the "fixed" ADF will match with another disk already in TOSEC!

I suggest to put those unnecessary ADFs into a separate DAT as they simply are NOT BAD. They're just unusable the way they are spread on the net.

mr_0rga5m · 28 March 2006, 11:05

Great detective work andreas .. Well done mate.

Methanoid · 28 March 2006, 13:49

Half the problem with these getting spread is that Tosec renamers put them in the dats.. if they didnt then those would die out in time....

Dont even get me started on the Alts.... IMHO there should be a util to patch them back to the confirmed working version and then they also would die out.. who wants to collect 10 versions of the same title??

Adderly · 28 March 2006, 14:28

Quote:

Originally Posted by andreas

DMS files may contain ascii headers. If those are unpacked using xDMS on a win32 PC, the header will be placed at the beginning of the files and make the ADF unusable because the boot block data will be shifted!

I was shocked reading this and made a test with some of my dms files. Happily, it's not true for all headers. Indeed i think it must be a very seldom case. I unpacked all my dms files with xdms (V1.3) and all are fine. Lots of them had the scene typical headers with BBS advertising and cracker nfo's etc. They were unpacked correctly, headers stripped!
Sometimes xdms has problems with a file and fails while DmsPro can unpack them without problems, but you get an error message from xdms!
So, what version of xdms do you use? Can you supply a file.dms that xdms can't correctly unpack for me for testing? If you are right, i need to unpack some of my files again, but with the files i just tested it seems that xdms works fine even with headers on the dms...

Methanoid · 28 March 2006, 15:50

Or more simply... "What version of XDMS did you use?" ??

andreas · 31 March 2006, 16:47

Quote:

Lots of them had the scene typical headers with BBS advertising and cracker nfo's etc

Yep, that's just the ones I mean!

Quote:

Can you supply a file.dms that xdms can't correctly unpack for me for testing?

Ugh, this might take a while, but I promise to do what I can

My "ADF bible" might help here, though. That is my ascii text files where I note down this stuff, and that's also the secret why I am still quick in finding dumps named something very verbose (

) like 'dsk1901.dms' I uploaded back in 2002.

@Methanoid
v1.3, latest, as 1.2 caused too many corruption with ADFs (maybe rare bug, but it's there)

28 March 2006, 10:10	#1
andreas Zone Friend Join Date: Jun 2001 Location: Germany Age: 50 Posts: 5,857	Please avoid xDMS with DMS files which contain headers I've just decided to open this thread to clear up another obscurity and most probably explain those WAGONLOADS of recent [ b]- and [ o] adfs I found out about. Especially in Demos section, I found LOADS of ADFs which were marked either [ b] or [o] (overdump). The reason was not that obvious, until I unpacked them on REAL amiga with REAL DMS: DMS files may contain ascii headers. If those are unpacked using xDMS on a win32 PC, the header will be placed at the beginning of the files and make the ADF unusable because the boot block data will be shifted! That is, viewed with a hex editor in ascii mode, the resulting ADF will be something like Code: ...Game..XYZ...trained...by...Dummbeutel...of...Nixkoenners....DOS....Nup...dos.library .... To make this disk bootable again, you must strip off the header. Rule of thumb: from byte 0 to one byte before the 'DOS' And believe it or not: in most cases when doing this, the "fixed" ADF will match with another disk already in TOSEC! I suggest to put those unnecessary ADFs into a separate DAT as they simply are NOT BAD. They're just unusable the way they are spread on the net. Last edited by andreas; 31 March 2006 at 16:50.

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28 March 2006, 11:05	#2
mr_0rga5m Tik Gora :D Join Date: Oct 2001 Location: Round yo momma's Posts: 1,273	Great detective work andreas .. Well done mate.

28 March 2006, 13:49	#3
Methanoid Retired Quartex Sysop Join Date: Sep 2001 Location: Roman Verulamium Age: 58 Posts: 1,873	Half the problem with these getting spread is that Tosec renamers put them in the dats.. if they didnt then those would die out in time.... Dont even get me started on the Alts.... IMHO there should be a util to patch them back to the confirmed working version and then they also would die out.. who wants to collect 10 versions of the same title??

28 March 2006, 15:50	#5
Methanoid Retired Quartex Sysop Join Date: Sep 2001 Location: Roman Verulamium Age: 58 Posts: 1,873	Or more simply... "What version of XDMS did you use?" ??

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