27 Mar
2023
27 Mar
'23
2:44 p.m.
On 3/26/23 23:18, Ali via cctalk wrote:
To answer my own question apparently sun made a triple
density drive: SUN
370-1420. Based on online pictures it uses a 34pin connector although I
believe it is keyed differently than standard floppy drives. Also, I
couldn't find any info on its capacity other than the standard 720/1.44. Any
Sun enthusiasts can shed some light?
Most likely, the 3-mode drive. 8x1024 sectors on each track, giving a
capacity of about 1.23MB. Many PCs of the era could also handle the
drives, which would change spindle speed from 300 to 360 RPM. 3 mode
drives were manufactured right up until the end, but usually were
configured as 2-mode (720/1.44) unless jumpering changes were made to
the drive.
As an example, consider the very popular Samsung SFB-321B drive. Used
in many PCs; the OEM data sheet should still be online describing the
jumper changes. But Teac FD321HG and some HF drives could be made to do
the same trick, as well as Mitsubishi and Canon drives that I've worked
with. I don't know if the Mitsumis could do it also, but it wouldn't
surprise me. Many USB floppy drives will also handle 3-mode media and I
believe that Windows NT supported it right from at least 4.0.
The 1.23MB format was very popular in Japan, originating, I believe,
with NEC, who had the idea that all floppies should mimic the 8" drives.
Simplified things quite a bit. Since Japan was also dominant in CNC
PLCs, you'll find that the 1.23M format is one used by Mitsubishi/Mazak
on much of their gear.
--Chuck