Current source for RX50 media?

Ethan Dicks ethan.dicks at
Fri Jun 24 23:20:30 CDT 2016

On Sat, Jun 25, 2016 at 12:13 AM, Fred Cisin <cisin at> wrote:
>>> 2) It's been too long so I don't remember, but don't you use normal pc
>>> floppies (5.25) and PUTR can format them?
> That would be 80 TRACKS at 96 tracks per inch.

Right... 96tpi. Thanks.

> Those would be the 300 Oersted disks, same diskettes as "360K".
> Do NOT use the 600 Oersted "1.2M"/"HD" disks.

OK.  That's what I kind of remembered but didn't want to quote from
memory.  Personally, I've always had a stack of DEC RX50s, but I don't
think my friend will easily find them these days.

> Being Single Sided, it really won't hurt to use just the first side of a
> Double Sided disk.

Of course.

> 80 track V 40 track both call for the same chemistry of the coating, but you
> should probably bulk erase whatever you get.

Right.  Easy enough to do.

> If you use a PC to format them, the requirements are essentially the same as
> for a "720K" 5.25".  Formatting can not be done with a "360K" (40 track)
> drive, but can be done with a 1.2M drive, or with a 720K 5.25" (which aren't
> common in the PC world).

My usual 5.25" drive (I have several) is the Teac FD55GFR - strapped
for RX33 use with DEC controllers or strapped slightly differently for
PC use (I know the directions are floating around)

> There are a couple of potential complications to using a 1.2M drive, that
> can be gotten around in software.
> (96tpi track spacing,
> same write current, rotational speed and data transfer rate as for 360K)

I'll look deeper into those issues when we find some media.

> We all have our favorite and hated brands.
> Ones you buy now, would likely be used or New stale stock, but that probably
> won't be a problem if they were stored well.

Right... outside of eBay, the question is where to find them, now that
the particulars have been pulled out.


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