exxos's Atari, Amiga & retro forum

philbo34 wrote: 22 Dec 2020 18:48 feeling old now

maxell breaks the sound barrier ..... great advert with pete murphy from bauhaus

rubber_jonnie wrote: 22 Dec 2020 18:06

Steve wrote: 22 Dec 2020 13:21 I don't know if this is your problem with the floppys, but I heard that the chemical composition of the HD disks is different from the 720k ones. They work but apparently not as good for data integrity? Perhaps someone else might know about this, I can't remember where I read about it.

There is actually a difference between the materials used to make 1.44MB floppies and 720KB floppies.

The magnetic material in a 1.44MB disk requires a much stronger current to change it's magnetic state, so if you drop a 1.44MB disk into a 720KB drive, and format it at DD capacity, the chances are it will work, however you may later run into data integrity issues because the 720KB drive was not able to properly change the state of the magnetic material in the HD disk.

I say may "encounter data integrity issues" because I never had a problem doing it myself, but the possibility is that it is a long term effect, and is only seen over years.

I personally don't think it's a good idea to put anything of value you want to keep long term on a 1.44MB floppy disk formatted to 720KB in an ST.

I did once find an article explaining all of this, and I'll post a link if I can find it again.

EDIT:

On this Wikipedia entry https://en.wikipedia.org/wiki/Disk_density it states the following:

"Double density (DD) 3½-inch disks use an iron oxide coating, just as with 5¼-inch DD/QD disks. However, drives utilize stronger 670-oersted write heads and a narrower track width of 0.115 mm (0.0045 in) for a density of 135 tpi and 8717 bpi.

High density (HD) 3½-inch disks switch to a cobalt disk coating, just as with 5¼-inch HD disks. Drives use 700-oersted write heads for a density of 17434 bpi"

mrbombermillzy wrote: 30 Dec 2020 20:06 That thing is shaped like its meant to travel to the moon! :lol: