Amiga A1020 5,25" floppy drive

Tahoe

Collector Extrodinaire
AmiBayer
Joined
Jan 4, 2009
Posts
1,333
Country
The Netherlands
Region
Wilnis
Recently I acquired some parts from an american living in Holland. One of the things in this batch was an A1020 drive. I already own a nice clean drive, and this one was a little yellowed and is missing the Amiga badge at the front.

As you can see the top drive looks better than the one at the bottom.
image.jpg
 
Until I had a look at the bottom, this seems really cool. Makes me think this drive comes from West Chester!

image.jpg

(silly iPad, I can only add one attachment per post)
 
Last edited:
Although practically useless for most Amiga-related purposes, the A1020 is a collector's-fetish item...
 
I was going to ask what you use the drive for. I've got one but can't for the life of me know what I can do with it. :)

Heather
 
Yep, I knew about the PC emulation software so I should have been a bit more specific. Outside of the PC emulator, what are these drives used for? :)

Heather
 
Wow you could have a prototype there might be worth opening both
and compare them also that might be why it has no badge on it..(y)


:coffee:
 
Yep, I knew about the PC emulation software so I should have been a bit more specific. Outside of the PC emulator, what are these drives used for? :)

Quite honestly, nothing. Maybe apart from hoarding, there is no real use of actually connecting up the drive and using it. It goes nice with an A1000 and A1010 drive, maybe even connected to a sidecar.

The drive is 40 tracks, needs a mountlist on Amiga side and has no disk change. That means: 440K per disk (360K for PC) and you having to type in diskchange DFx: everytime you swap a disk... :)

---------- Post added at 14:26 ---------- Previous post was at 14:25 ----------

Wow you could have a prototype there might be worth opening both
and compare them also that might be why it has no badge on it..(y)

I'll have a go at it. I have a 1571 power supply, I might have a look if that fits in the A1020, that way I could also power one up (these drives are 110volts, connecting it to our 240volts sounds like a bad idea :blink: )
 
Double Sided, Double Density, 40 tracks.

This is an interesting post by Mark_K over at EAB:
As far as the Amiga was concerned, there were (at least) two different types of 5.25" floppy drive.

Commodore's own A1020 is a 40-track drive which can be used to access PC-format 160/180/320/360KB disks. It reports the correct 5.25" drive ID to trackdisk.device, so trackdisk knows to use different head step timings. 5.25" drives, at least 40-track ones, need slower head step timings than normal 3.5" drives.

In addition to using CrossDOS or the old PC Copy utility on the Extras disk to read/write PC disks, you can use a mount file to read/write 5.25" disks using trackdisk.device, 440KB on each disk. You can also use an A1020 to read
Atari 8-bit, Apple II and C64 disks. (In order to read all speed zones of C64 disks you need to adjust the drive speed slightly. But after doing that, reading C64 disks in an A1020 is massively faster than using a real 1541.)

Since the A1020 is a real 40-track drive, there would be no interchange problems with transferring data from Amiga to Atari or Apple II. However I don't think anyone ever wrote an Amiga program to write Apple II-format disks.

Most third-party 5.25" drives are different. They use 80-track drive mechanisms and don't report the drive ID as a 5.25" drive, so as far as the Amiga is concerned the drive is the same as a normal 3.5" one. So trackdisk.device automatically "sees" the drive and you can format disks to 880KB. (I'm not sure whether the head step delay for 80-track 5.25" drives needs to be longer than for 3.5" ones.)

Software like CrossDOS has an option to double-step the drive heads, so it's possible to read 40-track PC disks in an 80-track drive.

Some third-party drives also have a 40/80 switch. In "40" mode the drive steps its heads twice each time the Amiga tells it to move the heads. The drive heads are still the narrower 80-track width, so writing disks for reading later in a 40-track drive (e.g. PC or Atari 8-bit) doesn't work reliably.

5.25" high density drives/disks aren't usable on the Amiga.
 
Back
Top Bottom