Amiga 1,76 MB HD

[darefail]

Hi,
is there a possibility to format a dd or hd floppy disk to 1,76 mb?
If yes, what hardware do i need and how can i do it?
Thank you.

[Daedalus]

You need either a special Amiga HD floppy drive or a Catweasel floppy controller + standard PC floppy drive. With either of those installed, HD floppies will automatically be formatted to 1.76MB using the normal Amiga format commands.

[darefail]

I have a modified sony mpf920 pc floppy drive that reads and writes both dd and hd disks. Can i do it just having this?

[Daedalus]

When you say modified... Do you mean it runs at half speed for HD floppies? Because that's the only way the native Amiga floppy controller can cope with the data from the drive. If you mean it's just modified so it works as DF0: then it won't work for HD disks.

[darefail]

I can be sure that works as df0: and reads/writes hd disks.
Not sure about half speed but as long as i can use hd disks, isn't it working at half speed?

[ptyerman]

Now I'm confused!
In your first post you asked the question "if" it could be used to write a 1.76mb floppy.
But now your saying you are "sure" that it reads/writes a 1.76mb floppy.
If it's already working why are you asking if it could work?

[Daedalus]

Yep, I'm confused as well. Formatting a HD floppy to 880KB is not the same thing at all - any floppy drive can do that. If you can read or write a 1.76MB floppy, it *must* be running at half speed or else you're using a Catweasel or similar add-on controller.

[darefail]

i am sure that i can format a hd disk. Just this.. I never checked if it was 880 or 1.76.. i never thought it could be 1.76.
i just transfer adfs from pc to amiga. The adfs are 880, so i never thought if the blank disk that i use was larger..
how can i check it?

[Daedalus]

If you put a HD disk in and format it from Workbench, if it's 880KB then it doesn't work for 1.76MB disks. The format utility will automatically select the correct size for what the drive and disk can handle, so if you get 880KB, that's all it can do.

[ptyerman]

What Amiga model are you using? I've never had one myself but I'm pretty sure I read somewhere that "some" A3000's could read/write 1.76mb floppy disks. Anything else, you will need a floppy controller card that understands the format.

[Mrz]

all the Amigas excepting the A500 can use high density floppy drives and format disks at 1.76mb
the only hardware requirement is kickstart 2.0 or better

you only need an Amiga' high density floppy drive , that's all

[ptyerman]

That's interesting information I didn't know about, never looked into HD floppy's on a Amiga because never had a need.
So the standard controller can handle the HD drive then?

[Mrz]

Originally Posted by ptyerman

That's interesting information I didn't know about, never looked into HD floppy's on a Amiga because never had a need.
So the standard controller can handle the HD drive then?

yes it can handle, even the old Amiga 1000 with kickstart 2.0
but please note on the amiga the HD drive is slow,is not fast like in a PC
ie to format a 1.76mb disk takes the double of time of a normal 880kb disk

[ptyerman]

Interesting! I do know they was slow because of running at half speed, but I always thought they needed a floppy controller board to use them.
Thanks for that information, it's not something I will ever need or use but it's nice to know regardless.

[Daedalus]

Indeed, the half speed rotation of the HD floppies reduces the bitrate to the same as a standard DD drive so the normal Amiga hardware can handle it. Some A4000s even shipped with such a drive. But they're rare and expensive. I've heard tell of people modifying PC drives to rotate at half speed however, thus making them compatible...

Originally Posted by Mrz

all the Amigas excepting the A500 can use high density floppy drives and format disks at 1.76mb
the only hardware requirement is kickstart 2.0 or better

you only need an Amiga' high density floppy drive , that's all

Surely the "Amiga high density floppy drive" counts as a hardware requirement?

[nogginthenog]

Originally Posted by Mrz

all the Amigas excepting the A500 can use high density floppy drives and format disks at 1.76mb

You can use an external HD floppy drive in an A500. I used to own one (Power Computing brand?). It needs a software patch to write I seem to remember.

[darefail]

I am using A500 ks1.3 so there's no possibility to format a 1.76 floppy.
I thought that a standard pc floppy drive was spinning at 300rpm and amiga at 150rpm. Probably i am wrong..
When i modified my fdd (2 wires, cut trace..) i thought by doing this, i also reduced the speed.. that's why i got you confused before.. sorry guys

[zipper]

Originally Posted by Mrz

all the Amigas excepting the A500 can use high density floppy drives and format disks at 1.76mb

My A500 has been running a 1.76 Mb floppy drive for almost 20 years now.

[ptyerman]

Surely the "Amiga high density floppy drive" counts as a hardware requirement?

I bet they are as rare as hens teeth to find too these days!

[darefail]

Originally Posted by ptyerman

I bet they are as rare as hens teeth to find too these days!

There is one in ebay for 195 euros.. i think it is the only one there!