High density floppydrive on A2000?

[tonyvdb]

Is there a high density floppy drive that will work on an A2000 or was that a feature limited to the 3000 and 4000?
In relation to this question will an older Dell PC floppy drive work? I just want to be able to read the PC formatted 1.4K high density floppies so could it be placed in the second drive bay?

[guest11527]

Is there a high density floppy drive that will work on an A2000 or was that a feature limited to the 3000 and 4000?
In relation to this question will an older Dell PC floppy drive work? I just want to be able to read the PC formatted 1.4K high density floppies so could it be placed in the second drive bay?

To my very knowledge, the type of Amiga does not matter as far as the floppy is concerned. HD floppies suitable for an A4000 are also suitable for A3000s and A2000s. The problem rather is finding a HD floppy for an Amiga in first place.

Techically, the problem is the available bandwidth for transmitting the data from the floppy to the RAM. The DMA channel in Agnus is only capable for transmitting the DD data rate. This goes for all Amigas.  

HD floppies for the Amiga thus half the rotation rate - and by that cut the data rate to one half of that of a HD floppy for a PC - to allow Agnus to catch up with the transmission.

I do not know whether anyone tried, but theoretically PC HD floppies *should* work on the Amiga if the screen mode is a 31kHz mode, e.g. productivity. This doubles also the bandwidth for floppies (one DMA channel per horizontal blank, twice the horizontal frequency -> twice the bandwidth for the floppy).  

I do not know whether there are any other technical limitations.

[Oldsmobile_Mike]

@Thomas - I thought they were spun at half the rate because of the Paula, not Agnus?

OP - AFAIK an Amiga high density floppy will be "plug-and-play" on an A2000.  Probably needs 3.1, but I think you've got that covered already.  Other companies made high density floppy drives for Amiga's back in the day (Applied Engineering comes to mind), but those drives did require a software patch and you couldn't boot off them (that's just from memory).

Edit - just googled up this thread:  http://eab.abime.net/showthread.php?t=55344   Lot of information here.

[psxphill]

@Thomas - I thought they were spun at half the rate because of the Paula, not Agnus?

Probably both actually, I'm not sure agnus would be able to give paula more bandwidth.

[tonyvdb]

Will the Chinon FZ357 work? or must it have the "a" in the model number?

[mechy]

Will the Chinon FZ357 work? or must it have the "a" in the model number?

Any amiga HD floppy will work on any amiga with 2.x roms and above.

Some 4000's came with a full height HD floppy,and that will fit the 2000 exactly,with a white face plate though.

3000 drives are usually missing the front bezel.

i thought i was paula also missing the bandwidth to run at high density.

PC HD floppies can be modded as double density,but will not work as high density without some serious mods,and most don't work reliably.

There were some out there form the aftermarket like "The real HD fix" from AMTRADE  i think it was.

[tonyvdb]

Ok but the Chinon FZ357A is the model thats in the A4000 I have. The one I found on line is a Chinon FZ357 Missing the "a" in the model number and I found another that was is an FG not FZ

Ok, turns out the FZ357 can be made to work.
http://eab.abime.net/showthread.php?t=9365

[psxphill]

Ok, turns out the FZ357 can be made to work.
http://eab.abime.net/showthread.php?t=9365

That thread is about using a HD drive with 880k disks, it doesn't do anything for using 1.76mb disks.

AFAIK the A2000 motherboard can only generate the drive ID for a 880k disk, so you need a special drive that can generate either an 880k or 1.76mb ID depending on what disk is in the drive and jumper the A2000 to say the drive is not present (all this does is stop the motherboard generating a conflicting ID). The drive also needs to slow down when you insert a HD floppy of course. This is essentially what an FB357A/FZ357A is, I assume the A means Amiga and without it you can't get HD disks working.

The only other reliable solution were the external laptop drives that Dell offloaded after commodore went bankrupt.

If someone reverse engineered the FB357 and FB357A then it's possible you could figure out how to modify one into the other. It might involve designing a new board which might be a good project for kickstarter.

[mechy]

Ok but the Chinon FZ357A is the model thats in the A4000 I have. The one I found on line is a Chinon FZ357 Missing the "a" in the model number and I found another that was is an FG not FZ

Ok, turns out the FZ357 can be made to work.
http://eab.abime.net/showthread.php?t=9365

it must be the "A".  i tried converting a fz357 but its hopeless as highdensity.

[tonyvdb]

If someone reverse engineered the FB357 and FB357A then it's possible you could figure out how to modify one into the other. It might involve designing a new board which might be a good project for kickstarter.

This would be a great project for Amigakit?

[mechy]

That thread is about using a HD drive with 880k disks, it doesn't do anything for using 1.76mb disks.

AFAIK the A2000 motherboard can only generate the drive ID for a 880k disk, so you need a special drive that can generate either an 880k or 1.76mb ID depending on what disk is in the drive and jumper the A2000 to say the drive is not present (all this does is stop the motherboard generating a conflicting ID). The drive also needs to slow down when you insert a HD floppy of course. This is essentially what an FB357A/FZ357A is, I assume the A means Amiga and without it you can't get HD disks working.

The only other reliable solution were the external laptop drives that Dell offloaded after commodore went bankrupt.

If someone reverse engineered the FB357 and FB357A then it's possible you could figure out how to modify one into the other. It might involve designing a new board which might be a good project for kickstarter.

this is not true, any Amiga from a500 to 4000t with at least 2x rom and paula will work for high density drives including the 2000. my 2000 has HD floppies in it from a 4k. Even the a1000 can use a HD floppy if softkicked to 2x rom + or a rom board is installed with real 2x rom.

The dell drives did work as hd if you want externals, and power computing made a hd drive also,but the power computing one needed drivers,and i find it not utterly reliable-but it may just be the drive i got.

[psxphill]

this is not true, any Amiga from a500 to 4000t with at least 2x rom and paula will work for high density drives including the 2000. my 2000 has HD floppies in it from a 4k. Even the a1000 can use a HD floppy if softkicked to 2x rom + or a rom board is installed with real 2x rom.

What is not true? Because I can't see what this relates to in my post.

and power computing made a hd drive also,but the power computing one needed drivers,and i find it not utterly reliable-but it may just be the drive i got.

None of the power computing drives were reliable.

[Oldsmobile_Mike]

What is not true? Because I can't see what this relates to in my post.

Geeze Louise you guys, I know it's only Monday and all, but:

AFAIK the A2000 motherboard can only generate the drive ID for a 880k disk

this is not true, any Amiga from a500 to 4000t with  at least 2x rom and paula will work for high density drives including  the 2000.

[psxphill]

Geeze Louise you guys, I know it's only Monday and all, but:

The A2000 (or A500/A1000) cannot generate the right drive id for a 1.76mb disk, which is why the floppy drive needs to do it.
You need a special drive that does it (like the 357A from an A4000)... Which is the drive mechy used anyway, so I don't get his point.

But yeah it's only Monday.

[Oldsmobile_Mike]

What you quoted of mine was right and mechys response is irrelevant.

All right dude, somebody needs to take a chill-pill.

Also, this has gotten way off course from OP's original question, which was "can an A2000 use a high density drive?" -- I think that's been answered -- "Yes, it can, under certain conditions".  LOL.