"Mixed-Mode" Amiga disks

andreas · 25 July 2001, 22:56

Hi,

didn't know where to put this, for it's neither a request nor a problem with a specific game, anyway feel free to move it if you think it doesn't belong here.

Recently, I learnt to know something about a "floppy disk format" I've never known before, consisting of a mixture of the common formats "DOS" and "NDOS", apparently used in my Soldiers of Hell crack of Cadaver - Last Supper.

Well someone pointed me to that - is it true that this game came on a "mixed-mode" floppy? I don't remember anything like this. I only witnessed a huge size decrease when FILECOPYing the game files to a fresh disk (about 600k). This told me that I had better _not_ filecopy this game. Anyway, for me it looked like a "normal" AmigaDOS disk.

Twistin'Ghost · 26 July 2001, 20:16

Actually, Codetapper has discussed this in a different thread (sorry I don't have it handy, but hopefully one of the thread-location fetishists will help you out here). But it is not really uncommon in games. I was just looking at a copy of European Championship '92 and disk 1 appeared to be DOS (although with no files) and disk 2 was NDOS.

I don't recommend filecopying any commercial games, btw. DMS on an Amiga or zipped adf's on the PC.

andreas · 26 July 2001, 20:39

Twistin', careful.

I was just talking here about both DOS and NDOS on *ONE* disk

Amiga1992 · 26 July 2001, 22:34

Twistin's European Championship '92 example is just like what you say, Andreas. Teh disk shows up as DOS, but has no files inside. But it's raelly full of stuff! It just uses a small part of the disk as DOS to show up a dupe directory, or something.

TikTok · 26 July 2001, 22:52

Somewhat related...I think the coverdisks from ST/Amiga Format (when it was one mag) were dual formatted for the ST and the Amiga, as were several early games I believe (I remember Starglider 2 being mentioned).

And there are quite a few games that appear to be DOS, but then show no files at all under workbench. Jimmy Whites Snooker is one example IIRC.

andreas · 28 July 2001, 19:07

@Akira

So complex? I'd rather think with EC '92, you're describing a plain AmigaDOS disk where the directory/file entries have just been made invisible (like BUDOKAN which I described in another (older) thread, the files are still there but inaccessible when you do a 'dir').
AFAICS, European Championship '92 is _not_ a disk that contains any NDOS part, which would be what I was talking about. It's actually a "manipulated" AmigaDOS disk (like the Budokan one), but it's a different thing to a disk whose structure is really a mixture of DOS and NDOS..

Amiga1992 · 28 July 2001, 21:52

Hmm.. could be that, but how can you test that it is that way really? I have many disks that act like that, and from what Codetapper said, I understood they only kept a small block of DOS to show up a fake directory.

andreas · 28 July 2001, 23:05

OK, let me give you an example: BUDOKAN.
Even after the "removal" of the entries so they aren't listed when doing a "dir", each and every block's first longword is one of "$00000002" (root block), "$00000008" (data block) or any similar stuff with special meaning (eg $00000010).

On the one hand, I define a real AmigaDOS disk as a disk which has a *straight* structure and 1760 blocks. NDOS disks (usually) have custom block size and/or number.
On the other hand, I define it as a disk which has a ROOT block on Block #880 and nowhere else. (Side-note: BOTH MUST have their BOOT block on Block #0.)
Take X-Copy: you can only list the directory of the disk if block 880 has the structure it expects (i.e. containing directory entries) -- you get an error message "not a dos disk!" if you try it with a NDOS disk.

Twistin'Ghost · 29 July 2001, 13:05

And another possibility is that maybe dual-format disks are special formatted as partitions, like you can do with Zip disks (at least on the AMiga you can!)

Amiga1992 · 29 July 2001, 20:46

You can partition ZIPs on an Amiga? didn't know that. I should try and connect my zip drive to the miggy... will disks written on the Amiga be read by the PC too? this could be a useful transfer method.

Twistin'Ghost · 29 July 2001, 21:48

OK, from what I remember back in the zip disk swapping days was that Amigas and Macs can format a dual partition disk. My Mac friend would give me a zip disk full of files and try to be a smart-ass by making two partitions: one Mac and the other PC. I was able to read both. But only the PC partition shows up on the PC.

So I returned the newly formatted zip disk to my Mac friend, but with three partitions: PC, Mac and Amiga. Needless to say, he couldn't read the Amiga partition.

Amiga1992 · 30 July 2001, 04:07

Haha, amazing! You will have to give me a few pointers so I can start using the zsip with my miggy. I have to buy an idefix interface soon, so taht will allow me to hook up the zip.

25 July 2001, 22:56	#1
andreas Zone Friend Join Date: Jun 2001 Location: Germany Age: 50 Posts: 5,857	"Mixed-Mode" Amiga disks Hi, didn't know where to put this, for it's neither a request nor a problem with a specific game, anyway feel free to move it if you think it doesn't belong here. Recently, I learnt to know something about a "floppy disk format" I've never known before, consisting of a mixture of the common formats "DOS" and "NDOS", apparently used in my Soldiers of Hell crack of Cadaver - Last Supper. Well someone pointed me to that - is it true that this game came on a "mixed-mode" floppy? I don't remember anything like this. I only witnessed a huge size decrease when FILECOPYing the game files to a fresh disk (about 600k). This told me that I had better _not_ filecopy this game. Anyway, for me it looked like a "normal" AmigaDOS disk.

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26 July 2001, 20:16	#2
Twistin'Ghost Give up the ghost Join Date: Apr 2001 Location: U$A Age: 33 Posts: 4,662	Actually, Codetapper has discussed this in a different thread (sorry I don't have it handy, but hopefully one of the thread-location fetishists will help you out here). But it is not really uncommon in games. I was just looking at a copy of European Championship '92 and disk 1 appeared to be DOS (although with no files) and disk 2 was NDOS. I don't recommend filecopying any commercial games, btw. DMS on an Amiga or zipped adf's on the PC.

26 July 2001, 20:39	#3
andreas Zone Friend Join Date: Jun 2001 Location: Germany Age: 50 Posts: 5,857	Twistin', careful. I was just talking here about both DOS and NDOS on ONE disk

26 July 2001, 22:34	#4
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	Twistin's European Championship '92 example is just like what you say, Andreas. Teh disk shows up as DOS, but has no files inside. But it's raelly full of stuff! It just uses a small part of the disk as DOS to show up a dupe directory, or something.

26 July 2001, 22:52	#5
TikTok Registered User Join Date: Jul 2001 Location: Malayasia Age: 43 Posts: 657	Somewhat related...I think the coverdisks from ST/Amiga Format (when it was one mag) were dual formatted for the ST and the Amiga, as were several early games I believe (I remember Starglider 2 being mentioned). And there are quite a few games that appear to be DOS, but then show no files at all under workbench. Jimmy Whites Snooker is one example IIRC.

28 July 2001, 19:07	#6
andreas Zone Friend Join Date: Jun 2001 Location: Germany Age: 50 Posts: 5,857	@Akira So complex? I'd rather think with EC '92, you're describing a plain AmigaDOS disk where the directory/file entries have just been made invisible (like BUDOKAN which I described in another (older) thread, the files are still there but inaccessible when you do a 'dir'). AFAICS, European Championship '92 is _not_ a disk that contains any NDOS part, which would be what I was talking about. It's actually a "manipulated" AmigaDOS disk (like the Budokan one), but it's a different thing to a disk whose structure is really a mixture of DOS and NDOS..

28 July 2001, 21:52	#7
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	Hmm.. could be that, but how can you test that it is that way really? I have many disks that act like that, and from what Codetapper said, I understood they only kept a small block of DOS to show up a fake directory.

28 July 2001, 23:05	#8
andreas Zone Friend Join Date: Jun 2001 Location: Germany Age: 50 Posts: 5,857	OK, let me give you an example: BUDOKAN. Even after the "removal" of the entries so they aren't listed when doing a "dir", each and every block's first longword is one of "$00000002" (root block), "$00000008" (data block) or any similar stuff with special meaning (eg $00000010). On the one hand, I define a real AmigaDOS disk as a disk which has a straight structure and 1760 blocks. NDOS disks (usually) have custom block size and/or number. On the other hand, I define it as a disk which has a ROOT block on Block #880 and nowhere else. (Side-note: BOTH MUST have their BOOT block on Block #0.) Take X-Copy: you can only list the directory of the disk if block 880 has the structure it expects (i.e. containing directory entries) -- you get an error message "not a dos disk!" if you try it with a NDOS disk. Last edited by andreas; 28 July 2001 at 23:11.

29 July 2001, 13:05	#9
Twistin'Ghost Give up the ghost Join Date: Apr 2001 Location: U$A Age: 33 Posts: 4,662	And another possibility is that maybe dual-format disks are special formatted as partitions, like you can do with Zip disks (at least on the AMiga you can!)

29 July 2001, 20:46	#10
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	You can partition ZIPs on an Amiga? didn't know that. I should try and connect my zip drive to the miggy... will disks written on the Amiga be read by the PC too? this could be a useful transfer method.

29 July 2001, 21:48	#11
Twistin'Ghost Give up the ghost Join Date: Apr 2001 Location: U$A Age: 33 Posts: 4,662	OK, from what I remember back in the zip disk swapping days was that Amigas and Macs can format a dual partition disk. My Mac friend would give me a zip disk full of files and try to be a smart-ass by making two partitions: one Mac and the other PC. I was able to read both. But only the PC partition shows up on the PC. So I returned the newly formatted zip disk to my Mac friend, but with three partitions: PC, Mac and Amiga. Needless to say, he couldn't read the Amiga partition.

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30 July 2001, 04:07	#12
Amiga1992 Registered User Join Date: May 2001 Location: ? Posts: 19,645	Haha, amazing! You will have to give me a few pointers so I can start using the zsip with my miggy. I have to buy an idefix interface soon, so taht will allow me to hook up the zip.