4 floppy disk drives on a PC?

[Doc Shipley]

Patrick Finnegan wrote:

> Doc Shipley declared on Monday 17 January 2005 11:04 pm:
> 
>>Dwight K. Elvey wrote:
>>
>>>1. A truely blank disk ( bulk erased ) can be formatted
>>> and written on by a 1.2M drive and will work in most
>>> cases on a 360K drive. This may written on by a 360K
>>> drive as well and still work on a 360K.
>>>2. Once a disk has been written on first by a 360K drive
>>> and then a 1.2M, it can only be read on a 1.2M drive!
>>>
>>>That's life.
>>
>>   No, that's wrong.  At least, it's not necessarily true.
>>
>>   I have formatted disks for an RX50 on the 1.2MB drive, written data
>>to them on that drive, and used them on a PDP-11.  I have also used
>>floppies to back up an RSX-11S disk on "real" RX50 disks, transcribed
>>that to PC, overwritten them on the PC without a low-level format, and
>>read them on the PDP-11.  I have had some floppies fail, but they
>>always failed either on the RX50 drive *before* they were ever in the
>>1.2MB drive, or they failed format on the 1.2MB drive before they ever
>>made it to the PDP-11.
>>
>>   I don't doubt the information I'm reading, that the track written
>>by the 1.2MB drive is narrower than the track written by a native 360K
>>drive.  I'll even stipulate that my experience is limited to writing
>>disks for PDP-11s and the Altos 580 (DSQD I think; I haven't played
>>with that box in a long while), so I can't speak to the reliability on
>>other platforms.
> 
> 
> Umm, the RX50s and Altos 580 floppies you've used are 80-track (96tpi) 
> disks just like 1.2MB floppies.  360k floppies are 40-track (48tpi) 
> disks.  So, they're the same track width as a 1.2MB disk, not a 360k 
> disk.

   Oh.

<Emily LaTella>
   Never mind.
<Emily>


	Doc