On Tue, Feb 22, 2022, 8:43 PM Jay Jaeger via cctalk <cctalk@classiccmp.org> wrote:
> On 2/22/2022 6:12 PM, js--- via cctalk wrote: > > > > On 2/22/2022 7:00 PM, Ray Jewhurst wrote: > >> I read that you can indeed use a standard 1.2 Meg drive and that you > >> can also use DSHD 5.25 disks in place of RX50s. Is there any truth in > >> this? If there is it will be much easier and cheaper to make disks for > >> my Rainbow. > > > > > > As Chuck noted, I'd think you'd want to use 360K media -- not DSHD > > diskettes... and ensure that the 1.2MB drive is slowing down to 300RPM > > with a data rate of 250KHZ. > > > > These features will depend on the 1.2MB drive you have, as well as your > > FDC and imaging software. > > > > - John Singleton > > Writing a 360KB or RX50 diskette with a 1.2MB drive is a path to a lot > of frustration. Not only do you have to double step the drive (software > often takes care of that part), but the tracks written will be narrower > than a real RX50 / 306KB drive, providing a smaller signal/noise ratio. Not true. Not for RX50 at least. Both the 1.2MB format and the RX50 format use 80 tracks. There is no double stepping or half width tracks involved. > And, if you don't start with completely magnetically erased media, any > left over junk in any data left over may be picked up by the RX50 head. > Also not true. Writing a full track to format it results in well formed media. As long as you don't use HD media. DD or QD media works just fine. Been there, done that. > I have as well, and things don't work the way you say. The TEAC 55 drives are able to do this. In college I exchanged data between a data collection AT and a MicroVAX ii on RX50 media. It was sometimes formatted on my Rainbow at home and later on the AT since I got tired of being in the loop. We had none of these problems as long as we avoided HD media. Warner > JRJ >