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Turning double sided 8" disks into useable RX01/RX02 media

L

Lou - N2MIY

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I was making some RX01 floppies for a needy forum member and decided to photograph my process for turning double sided 8" floppies into "flippy" RX01/RX02 media. "Flippy" because RX01/RX02 were only written on one side, and with approriate modification can be used on both sides.

RX01/RX02 are single sided disks. 8" single and double sided disks have the sector holes through the jacket clocked differently. For some reason, I seem to come across much more double sided media than single sided media. Here is my process for making the double sided media usable in the RX01/RX02 drive....

These are the tools: http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18055 . The most important tool is an old jacket from an RX01 floppy. It will be used as a template. The media must be removed. It can be done by using a razor blade to slit open the top edge of the jacket. The other tools are a fine point sharpie, a hand hole punch, and a business card.

Use the jacket as a template. See here: http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18056 that the sector holes are in different places. The disk on top is a double sided disk, and the jacket in the back is from a single sided disk. Lay the jacket over the double sided disk and mark : http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18057 the front: http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18059 and the back: http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18058 . The template needs to be flipped on both sided of the double sided disk to make the two marks per side. You'll be punching four new holes in total.

Slide the business card in the spindle hole under where the new holes need to be punched. The card protects the media surface from the hole punch. http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18060 . Then punch it, used the sleeve the disk came with to protect the media from being touched through the head access hole in the jacket: http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18061 . Then punch the other side.

When you're done http://www.vintage-computer.com/vcforum/album.php?albumid=229&attachmentid=18062 you have a flippy single sided disk. It can be formatted as RX01 in a PC with PUTR, in a DSD440, or by other means (not involving a real RX01 drive.)

Lou
 
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I don't know if it matters on the RX02 drives, but some floppy drives, such as Qume DT/8's will get confused by converted disks unless the original SS hole is covered by something. This especially holds if you're working with HS diskettes (I know, not DEC, but I thought I'd mention it).

Oh, a slight nit--soft-sector floppies don't have sector holes, just an index hole. Sector holes are for hard-sectored floppies, which also contain an index hole, positioned exactly between two sector holes. And if you add sigle-sided index holes appropriately to both sides, you have an instant "flippy".
 
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Chuck,

You are right, it's the index hole. I am half-tempted to correct the original post.

I can also see how some (non-dec) drives could be confused. If a drive can use both single and double sided disks, it may have index photogates across both single and double sided holes. A temporary piece of black vinyl tape may be needed to cover the double sided hole. The RX01/02 will not have this problem because it only has the single sided location photogate.

Once I had three boxes of hard sectored floppies (the price was right). But, I really needed RX01s. On one disk, I carefully slit the jacket, removed the media, and covered all but one sector hole with a ring of thin dark vinyl tape, then put the media back in the jacket and resealed the jacket. It did work, but I suspect that in the long term the edge of the hole in the vinyl tape may catch something.

Lou
 
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Lou, I've also seen certain drives (e.g. Siemens FDD200) that, with the jumpers set to hard sector, will provide only the INDEX/ signal on the appropriate pin, whether or not the disk is hard-sectored or not. And I've run up against getting a batch of hard-sector disks formatted as soft-sector (i.e. the sector holes don't line up with sector boundaries). Someone evidently found that they could get a good price on HS floppies and so used those instead of SS ones.
 
Thanks Lou, I have box of NOS Dysan and I intend to try converting some as soon as I get time so your tutorial will be very useful, not going to do them all as another project is to bring my 1980's home brew 6809 Flex system back to life sometime, but that's for another forum.
DaveH
 
Here's how Cromemco dealt with the issue on their distribution disks; just move the sticker to wherever's appropriate for your drive:

8SS_DS.JPG
 
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