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PDP11 - RX01 Writing disks

@daver2 I have tried the bootstrap with a disk written for RX01 that "should" work.
Unfortunately when I start the bootstrap using 1000G, I see just the head load solenoids of both drives acting, but it does not look like the drive tries to read
 
You could always try swapping the physical drives in the RX01, then testing. If the problem still happens the issue is on the RX01 controller board. If not it's the 8 inch drive.
 
wa2flq said:
The following designations and products were common
  • SSSD => Single-Sided Single-Density (RX01)
  • SSDD => Single-Sided Double-Density (RX02)
  • DSSD => Double-Sided Single-Density
  • DSDD => Double-Sided Double-Density
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Just to ensure things are clear, there are only two types of media above: single-sided and double-sided. "Single density" and "double density" recordings are both done on the same media; the difference is in the signal sent to the drive (FM vs. MFM); standard density media will record both equally well. (This doesn't stop manufacturers from marking their media "double density," of course, but such a marking is meaningless except insofar as it means the media isn't high density.)
 
Chuck(G) said:
...and of course, if you've got a rig that uses 8" GCR (e.g. Future Data), nobody knows what to call the disks.
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You call them the same thing that you call them if you don't have that rig, since the Future Data system does not magically transform the diskettes you put into it into something else, or re-coat the inserted media, or anything like that.

I use the term "standard density," as the only other actually different media (as in, a different coating on the surface) that was ever in remotely common use is High Density.

(Well, that's technically not true, since 3.5" standard density media is a different coating, with a different coercivity, from 8" and 5.25" standard density media. Fortunately, it's rare to see 5.25" sleeves with 3.5" media in them, or vice versa. And consumers have, for whatever reasons, shown little propensity to try to use 3.5" diskettes in 5.25" drives or vice versa.)
 
cjs said:
I use the term "standard density," as the only other actually different media (as in, a different coating on the surface) that was ever in remotely common use is High Density.
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I'm not aware of any special "high density" formulation for 8" floppies--basically, it's all a matter of holes; viz, single-sided, double-sided, flippy, or hard-sectored (with the exception of the Memorex 650 type, all 32 hard sectors). Even Wang 8" so-called 16 hard sector floppies have 33 holes, with the hardware dividing the sector pulses.
8" drives with hard sector discrimination circuitry (e.g. Siemens FDD-200) can use hard-sectored floppies as soft-sectored ones, as the sector pulse is assigned to a different pin from the index.
That one really threw me with a customer sending a bunch of Fairchild Sentry hard-sectored disks, but written as soft-sectored. Before I realized what he'd done, I was going nuts trying to line up recorded sectors with the sector holes.
I'm not aware of this happening in the 5.25" world.
 
Chuck(G) said:
I'm not aware of any special "high density" formulation for 8" floppies...
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There was one. It was rare, but it existed and was commercially sold by Maxell, at least.
1713080349832.png

Chuck(G) said:
8" drives with hard sector discrimination circuitry (e.g. Siemens FDD-200) can use hard-sectored floppies as soft-sectored ones, as the sector pulse is assigned to a different pin from the index.
Click to expand...
Ah, that's interesting to know!

Also, I just realised I lied slightly when saying that diskettes sold as "single density" or "double density" were no different from each other. The media are of course no different, but if they happened to come pre-formatted (which, if I understand correctly, was a lot more common in the early 8" world than the early 5.25" world), the format on the diskettes would be one of the two. Each could be reformatted as the other, of course.
 
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