How can a floppy be a PC 720k disk and an Amiga 880k disk at the same time?

[dreamkatcha]

I've formatted a disk as an Amiga 880k disk using Amiga Explorer yet I can still access the PC files on it and the label is still in tact. What's that all about? :confused

Edit: Is is possible to use the extra formatting options with game disks? You know like caching, fast filing system etc or are these just for apps to be used in Workbench?

[fiath]

Different disk formats store things in different ways. PC disks for example have more integrity information that Amiga disks. The main reason for the size difference I would not be able to tell you since I do not know about PC 720 disks.

However (just as an example) other disk formats get more that 880Kb on. There was a util on aminet (PFS? FPS? something like that) that allowed you to store 980Kb on a DD disk.

This is probably by sacrificing header and integrity information.

I suspect many games do the same thing to cram on more data - no need to use crappy ADOS format (though many do - probably due to development cost of anything else more than anything)

[LUKas007]

Originally posted by Echostryker
I've formatted a disk as an Amiga 880k disk using Amiga Explorer yet I can still access the PC files on it and the label is still in tact. What's that all about? :confused
Can you explain what exactly the problem is about? ;)

Edit: Is is possible to use the extra formatting options with game disks? You know like caching, fast filing system etc or are these just for apps to be used in Workbench?

Yes, but that have to be DOS games, and you probably will have to copy the files elsewhere and reformat the disk in another AmigaDOS format... then copy them again on the disk.

[fiath]

I am so good at reading post properly... :rolleyes :o

[LUKas007]

Originally posted by fiath
I am so good at reading post properly... :rolleyes :o

Its really cool that you can read properly :laughing
Anyway, its NOT really connected with the topic of this thread...

[dreamkatcha]

Yeah, not really the answer to the question I asked, but interesting all the same, so thanks. :)

Thanks LUKas007. Getting the files off the disks and then putting them back isn't an issue - I bought a ton of DD disks for a ridiculously low figure from Yahoo auctions before it closed its doors for good. What's on them is identical on every disk so I just need to format them (which I can do from the PC side using Amiga Explorer) and then extract the ADF files to the disks (again from the PC side). I've been trying out all the various options in AE and it lets you format DD disks which are already formated as 720k PC format disks to 880k Amiga format disks so things couldn't be any simpler. :D

As a test run I transferred Turrican to a disk I formatted using the extra options and it booted fine. :cool

I don't think I've ever played a game or will ever want to, which needs to be run through Workbench so I don't think there will be a problem (assuming I've understood the terminology correctly).

[Akira]

I dont think I understand you fully... Are you saying you formatted an Amiga disk, on the PC, using Amiga Explorer? that sounds... improbable.

[LUKas007]

... exactly :confused

[Akira]

As a test run I transferred Turrican to a disk I formatted using the extra options and it booted fine.


Ok, I understood this part :P

You format the disk. Now it's in AmigaDOS format, with Caching, fastfilesystem, whatever you want.

Then, you unpack an ADF onto this disk, using AE.

What you have done, completely overwrites the format you did before. Turrican I is a NDOS disk. It doesnt give a damn if you formatted it in PC, Atari, or BBC Micro format. So those options you set before, mean pish to the game you unpacked.

As a matter of fact, you NEED NOT to format disks before unpacking ADFs onto them. Take a blank, unformatted disk. Chuck it on your Amiga. Use AE to unpack an ADF onto it. It will work just fine.

Also, to be true, I never found a damn of a difference in changing the filesystem to FastFileSystem, or to allow cacheing :P If there ARE differences, you can utilize them ONLY with AmigaDOS-format game disks. Not all games in AmigaDOS format boot onto the Workbench, that's a misunderstanding. Crazy Cars III, for example, is perfectly AmigaDOS compliant (I remember installing it by hand to the HD back then, assign here, assign there), and it never boots onto Workbench when you run it.

So...

I don't think I've ever played a game or will ever want to, which needs to be run through Workbench so I don't think there will be a problem


If you dont like something like Monkey Island, you wont boot onto Workbench for playing. And there are a few action games that boot onto workbench too.


Now if I understood correctly what you wrote initially (after reading your other post), I get it that you are formatting the disk on the Amiga through the PC... I dont know about the possibility of creating a double-format disk, I think it's unprobable. But I know you are not formatting disk on the PC with Amiga format. That's impossible.

[Syko]

Way back in the mist's of time, in a publishing house far, far away, there was a magazine for Amiga and Atari ST. They had dual format disks on the cover.

I haven't a clue how they did it, but if you can have Amiga/ST floppy's then why not Amiga/PC?

Cheers

[LUKas007]

The reason may be that the PC format might be completely different when comparing the Amiga and ST disk formats ;)

[dreamkatcha]

Ooh eck, it looks like I've caused a bit of confusion here, sorry. I really should stop missing out crucial details.

I connected my PC to my Amiga 1200 using a null modem cable, transferred the Amiga Explorer server software to the Amiga using CrossDOS and executed it from there. I was then able to put a disk in the Amiga DF0 drive and initiate a format from the PC side. Once you've got Workbench loaded and have double clicked on the AExlorer program you don't need to touch the Amiga again except to change disks. Extracting an ADF to DF0 simply involves dragging and dropping the ADF file onto the DF0 icon on the PC.

Thanks for putting me straight Akira - so it looks like I've been wasting my time formatting the disks before extracting to them. I won't bother in future then. That should really speed up the process.

I think this double format thing must have just been a misrepresentation on AE's part. Or maybe it works just like hard drives - you know how you can delete stuff but technically it's still there until it's overwritten properly. Then again it could have something to do with me mounting PC0 on the Amiga side. I decided to take that out of my startup folder anyway because I no longer need it there all the time now I have the AE server software transferred.

I think I've managed to confuse myself as well as you here. The Monkey Island series are actually some of my all time fave games, but I wasn't counting the WB startup sequence built into some games as being proper Workbench games - see what happens when you don't use an Amiga for a while - you start talking rubbish. :D I was thinking you'd have to load the full WB disk and then load the games through that. There are actually far more WB games than I first thought.

Edit: one benefit of formatting beforehand that I discovered was that it tells you if the disk is knackered so you'll know not to use it. I wonder if AE will report the same thing if it comes across duff sectors while it's transferring. Hope so.

[Twistin'Ghost]

That is a good point about the reporting of disk errors. I used to unwarp and undms downloads to floppies back in the day, fully unaware of the stability of the disk. But since I always kept the archived download, it didn't much matter.

An interesting part of this thread that deserves maybe some more attention is dual formatted disks. I think warp (or one of the mutant hacked versions) allowed you to archive and unarchive disks in PC and Atari ST formats (I assume they both are the same, but there might be a difference I am unaware of). I wonder if such a tool could be used to create a dual format floppy (Amiga/PC-ST). I can't see any reason why this wouldn't work, really...unless AmigaDOS (or M$-DOS) freaks on not having all the tracks available (maybe the dual format disks used a custom OS on the Amiga end?)

With zip disks (at least on the Amiga), you can create dual format disks for Amiga, PC and Mac. It accomplishes this by partitioning the disk. Theoreticaly, the same should be possible for a floppy, but maybe it would need a unique mountlist entry that defines the number of tracks that particular disk contains?

Just tossing out possibilities here...

[Codetapper]

Rob Northen was the first who made dual format disks for Amiga and PC widely spread - these were on the magazine Zero in the early days.

But he went one better than that and made tri-format disks - 3D Pool is the only one I can think of now but it has the Amiga, Atari ST and PC versions on the one DS/DD disk.

I maybe wrong here but I think the standard Atari ST format is actually the same as the PC - complete with naff 8.3 naming limitations. I assume he setup the disk in a way that the key parts of the disk on the Amiga (tracks 0 and 40) were valid and then whatever sectors on the Amiga side were needed for the game and on the Atari ST/PC side he did the same. The bootup sequence on the ST probably reads out of a file (like the Amiga's startup-sequence) so it would be possible for both an ST and PC user to run the correct file for their machine.

Probably :)

[Akira]

Originally posted by Syko
Way back in the mist's of time, in a publishing house far, far away, there was a magazine for Amiga and Atari ST. They had dual format disks on the cover.

I haven't a clue how they did it, but if you can have Amiga/ST floppy's then why not Amiga/PC?

Cheers

I didnt mean it was not possible, I mean it was not possible using that feeble Amiga Explorer thing! Of course they were possible using those disk duplicator device thingies...

[dreamkatcha]

Just out of interest what's the argument against using Amiga Explorer? Apart from the price (which isn't really an issue) and the speed, what else do you people have against the poor little guy? Is it that it favours PC people and you're all die hard Amigans?

TG - there would be an easy way of testing the error checking potential of AE as it extracts ADFs - I've got three floppies which couldn't be formatted using AE because they contain errors. Later on I'll try and extract an ADF to one of these disks that I know are defective and see if it spots the deliberate mistake. I'll report back a bit later on tonight.

[Akira]

Price and speed are key issues. I can get TwinExpress for FREE and it goes much faster..

If I am to pay, I'd get PC2Amiga. THE program. you mount a PC: device on the Amiga, and automatically have access to all its drives. Like the network Neighborhood thing on Windows. you can run stuff from the PC drives!

And I dont like this thing of making the Amiga a slave of the PC. is much better to have the Amiga making a slave out of the PC :D. YEs Im a die-hard Amiga fan :D

[dreamkatcha]

I tried extracting an ADF file to one of the disks I definitely knew was duff and it reported "error verifying disk track" right near the end in exactly the same place where I had problems formatting it previously, so it looks like AE has this angle covered. :cool

I see, Akira. I suppose it makes sense to want to work mostly from the Amiga if that's what you're most comfortable with. My situation is the reverse so I'm very grateful to AE for making such an idiot proof program. :D

I can't agree on the price issue though - technically they're both free, aren't they? There's no way I'd pay for what is little more than a pair of repackaged emulators which are available free online. Maybe if they were selling AE separately at a reasonable price I'd be happy to pay for it even if I knew where to get it free. I just don't take too kindly to being ripped off.

These other programs being faster is a good point, but then patience is a virtue. ;) I'm content to lose a bit of speed if it makes for a simpler transfer.

Maybe I'll change my mind about all of this when I find my Amiga feet again. :)

[Akira]

Well, if you use TwinExpress, you can do everything from the PC. but its shell interface is not as friendly as AmigaExplorer's graphic interface, I give you that.

I dont think PC2Amiga works on the PC as it works on the meega (ie showing you all the Amiga drives on the PC). Havent tried it much on my house, since I dont have a parallel cable and the serial method does not seem to work.

[RetroMan]

PC2Amiga works like a charm with serial cable :) Used it alot before I got my Network Card for my A1200 :D

[Akira]

I don't know, it just didn't work here! Strange thing...

[Mick_AKA]

Originally posted by Syko
Way back in the mist's of time, in a publishing house far, far away, there was a magazine for Amiga and Atari ST. They had dual format disks on the cover.

I haven't a clue how they did it, but if you can have Amiga/ST floppy's then why not Amiga/PC?

Cheers

Because Amiga and Atari Disks are both Double Density, all you have to do is put both Amiga and Atari Files on the disk, PC disks however are high density, as far as i know you cant get a half DD and half HD floppy disk!

[LUKas007]

Originally posted by Mick_AKA


Because Amiga and Atari Disks are both Double Density, all you have to do is put both Amiga and Atari Files on the disk, PC disks however are high density, as far as i know you cant get a half DD and half HD floppy disk!

Havent you heard of PC 720KB disk format ? It uses the same DD disks as Amiga(880KB) and ST do...

[Akira]

Originally posted by Mick_AKA

Because Amiga and Atari Disks are both Double Density, all you have to do is put both Amiga and Atari Files on the disk

That is wrong. Both disks are double density but the formats are COMPLETELY different!

However the PC and Atari disk filesystems are compatible.

[Mick_AKA]

well i have jpg images on DD disks that i can read fine with both my a1200 and atari 520stfm!

[Akira]

Of course, because your Amiga is loaded with CrossDOS surely, and CrossDOS reads the disk :P

[Mick_AKA]

yes but crossdos reads PC disks, the disk with the jpg's on is an atari st formatted disk, my pc will not read it but my amiga does and I can view the images perfectly with pegger.

[Akira]

Originally posted by Mick_AKA
yes but crossdos reads PC disks, the disk with the jpg's on is an atari st formatted disk, my pc will not read it but my amiga does and I can view the images perfectly with pegger.

Sorry, CrossDOS also reads Atari ST disks. I repeat, Amiga and St format have nothing to do with each other.

[Mick_AKA]

well then back to the question, how do dual format disks work?
I have dual format copy of carrier command that works with amiga (without crossdos) and atari st!

Oh and crossdos DOES NOT read Atari disks, I just tried it with loads of my Atari ST disks and you just get a Disk Warning box that reads:
Error Validating Disk

[Akira]

Yes it does read Atari disks. Except they are copyprotected I suppose, I dont have further information about the Atari St disk format.

And dual bot disks were made like it was described above. With special machinery or something.

[Unregistered]

Way back in the mist's of time, in a publishing house far, far away, there was a magazine for Amiga and Atari ST. They had dual format disks on the cover.

Cheers

I have a mate, who has access to tri format cover disks. They really did get my attention. the idea of a cross platform virus came to mind when I saw that. The tri format disks do look interesting. I never had a go, I just fired up Rick Dangerous and played that instead.

I think "Victory Road" runs on both the Atari and the Amiga. Just yeah runs different versions. I thought their may of been code in the program, that hit some address's to see if it was running on a amiga or a Atari.

[Mick_AKA]

I have a copy of lemmings that runs on IBM PC, Atari St and Amiga so I would assume that is a Tri-Format disk, dont know much else about it really!

[fiath]

IIRC this is probably Rob Northen's tri-boot block. I think he first did a dual boot (Ami/ST) and (Ami/PC) then all three. Quite clever.

[whiteb]

I've formatted a disk as an Amiga 880k disk using Amiga Explorer yet I can still access the PC files on it and the label is still in tact. What's that all about? :confused

Edit: Is is possible to use the extra formatting options with game disks? You know like caching, fast filing system etc or are these just for apps to be used in Workbench?

DD disks were actially 1MB disks but the formatting of the perticular system determined the max size.

Its similar to how CD's work (different tech), You can have a 700MB Recordable CD, but how can you put SVCD's 820MB onto a disk ?
Its all down to the format, SVCD doesnt use error correction areas of the disk.

There are device drivers on Aminet that allowed around 950K on a disk, and sometimes some MFM formats pushed *PAST* 1MB.

[edit] Directory cache and International mode of Fast file system are Amiga only. MSDOS does not support anything like that.