External 3.5" Floppy Disk Drive questions 720kb or 1mb?

[256 colors]

What's the difference between the these two drives which is best for me terms of compatibility does the the 720kb or 1mb matter

 

These are two drives i'm looking:

 

https://www.ebay.co.uk/itm/Atari-ST-E-STFM-1040-Mega-Heavy-Duty-External-3-5-Floppy-Disk-Drive-1MB-DSDD/372652331099?hash=item56c3cf505b:g:h8MAAOSwxCBcs42S

https://www.ebay.co.uk/itm/Atari-520-1040-ST-STFM-STE-Mega-Computer-External-Floppy-Disk-Drive-720K-DS-DD/153456524995?hash=item23bab8bec3:g:cg4AAOSwG8ZcuNWo

Edited April 29, 2019 by 256 colors

[ParanoidLittleMan]

Well visible difference is that one seller claims something what is not true. There are no 1MB drives.

Personally, I think that in both cases prices are way too high. And lifetime to expect is low.

 

What matters is DS DD - means double sided, double density. Usually it is called 720 KB drive, but that's just usual PC format. Especially in case of Atari ST it is not much used. 800 KB format rather.

But you can go up to some 920 KB, at price of lower reliability and slower work. If find floppy disks in good shape,

To add that you may expect problems with disk change detection, because Atari used non regular way for that, and only some older drives support it. And such drives are mostly dead now. It is easy to put any (PC) DS DD floppy drive in case, and connect it properly. That works well with Atari except mentioned disk change detection problem, what will not see after short test. The result may be corrupted data.

More about: http://atari.8bitchip.info/flomodam.html

[JamesWD]

1Mb unformulated capacity, really just a marketing ploy.

 

Once formatted with boot record, FAT table etc. and depending on track and sectors used actual usable space is ~ 720Kb - 900Kb (the higher you go the more unreliable it becomes).