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Caluser2000
November 15th, 2011, 09:06 PM
Last week I asked to aquire some 3.5" DD/DS 720k disks. Turns out an item of test equipment at work is being put back into service. Needless to say the chap was over the moon when I turned up at work the next day with few.

Seems we'll need a steady reliable supply and I don't want to deplete what little I have. Anyone dealt with the sellers of those disks on EBay at all?

Thanks in advance.

Ole Juul
November 15th, 2011, 09:49 PM
I'd go local. Check out our member stone. (http://www.vintage-computer.com/vcforum/member.php?9749-Stone) His sig line is:

* If you're looking for DS/DD or DS/HD 3.5" or 5.25" floppy disks, PM me. I've got plenty of new, used and reformatted/overlabled disks for sale. *

Caluser2000
November 15th, 2011, 10:35 PM
Cheers. Been a while since I've popped in. I have suggested using DS/HDs with the ID hole covered in the interim if he's really desperate. One of the bosses even asked if we still had PCs with fdd installed. Thankfully my work desktop does as do a few PCs in the instrument shop. He seemed quite surprised.

mbbrutman
November 16th, 2011, 06:06 AM
Just a gentle reminder to pick subjects for threads that reflect what the thread is about. "Interesting request" is far to generic to be interesting to anybody.

deathshadow
November 16th, 2011, 07:01 AM
I have suggested using DS/HDs with the ID hole covered in the interim if he's really desperate.
I wouldn't call that desperate -- I don't think I've seen a 'real' 720k floppy since the early 90's... and those were for a Alesis Datadisk Midi Sequencer... just put a piece of tape over the hole that's not the write protect, and be done with it.

Chuck(G)
November 16th, 2011, 08:44 AM
The big problem is that a DSHD with a blocked media-sense hole is not the same as a real DS2D. It might be okay in a pinch, but I wouldn't give a plugged nickel for its long-term stability.

The DS2D coating is thicker, with a larger particle size and higher "loading" as well as having slightly different magnetic characteristics.

There are NOS DS2D floppies still around, but you'll have to look for them--and be prepared to pay the market price.

deathshadow
November 16th, 2011, 08:54 AM
It might be okay in a pinch, but I wouldn't give a plugged nickel for its long-term stability.
We're talking 3.5" floppies, they had long term stability? In ANY format?

I've got 30 year old 5.25" disks that work fine today... I've never had a 3.5" disk in ANY format last more then three months. The only selling point they EVER had was capacity -- it sure as shine wasn't reliability, even with the silly plastic case... and the doors that tend to break off in drives and springs that scratch up the surface.

Used to have a co-worker who went around the office and ripped all the hoods off the 3.5's, because he was sick of having to try and fish them out of drives.

Chuck(G)
November 16th, 2011, 09:27 AM
Don't lecture me on stability of magnetic media.

That being said, I have lots of 3.5" DS2D floppies (it used to be our standard distribution medium) that are just fine 20 years after they were written. See an earlier post on re-cycling old (>10 years) 3.5" media. My own attempts at recycling old 3.5" media over a sample space of about 200 floppies shows both 3.5" DS2D and DSHD seem to have a recovery rate (i.e. all-good, no flaws) of between 50-60 percent. If you find one of those disks, it's pretty much good long-term--I've used and re-used floppies from the good pile with no problems.

What this says to me is that most 3.5" floppies have issues right out of the box--and that a further culling yields the dependable disks.

How many 3.5" DS2D floppies does the OP need? If it's just a hundred or so and he's willing to take culls, maybe I can help out.

MikeS
November 16th, 2011, 09:34 AM
Don't lecture me on stability of magnetic media....LOL!

I've still got some NOS bulk 3.5DD diskettes as well (unculled ;-) ).

Caluser2000
November 16th, 2011, 10:24 AM
I wouldn't call that desperate -- I don't think I've seen a 'real' 720k floppy since the early 90's... and those were for a Alesis Datadisk Midi Sequencer... just put a piece of tape over the hole that's not the write protect, and be done with it.Well here's your chance to get some- http://floppydisk.com/ It was a common format for embroidery machines.

Cheers for the feedback guys.

Yea the title was a bit so so but I wasn't expecting a request such as that. And usually old hands have a quick squiz to see what the fuss is about. I'll find a bit more detail about the piece of equipment they're to be used in.

Chuck(G)
November 16th, 2011, 10:40 AM
Note that floppydisk offers either NOS or recycled media--I don't think that anyone's actually made DS2D floppies in at least 5 years. $5 (NOS) or $4 (recycled) does seem to be a bit steep.

Not long ago, I checked with Athana for a customer who wanted thousands of DS2Ds. Athana responded by saying that nobody made them or was likely to make them and good luck with the floppydisk.com people.

Personally, if you're dealing with that kind of money, I'd recommend that you investigate the emulators being offered by the CNC and embroidery retrofit people.

Caluser2000
November 16th, 2011, 03:20 PM
Note that floppydisk offers either NOS or recycled media--I don't think that anyone's actually made DS2D floppies in at least 5 years. $5 (NOS) or $4 (recycled) does seem to be a bit steep.

Not long ago, I checked with Athana for a customer who wanted thousands of DS2Ds. Athana responded by saying that nobody made them or was likely to make them and good luck with the floppydisk.com people.

Personally, if you're dealing with that kind of money, I'd recommend that you investigate the emulators being offered by the CNC and embroidery retrofit people.Thank you very much for the suggestion Chuck. I've passed that on to the department boss and he reckons it's the way to go alright. Was quite greatful too. I'll let you know how it pans out. Turns out the item is an rotor/propeller balancer test set based around a 8088 cpu, so well within the realms of this forum ;). It was going to get biffed but now hopefully will see a new lease of life.

I did get a quick response to my email from the floppydisk.com people btw.

Caluser2000
November 18th, 2011, 02:13 PM
Managed to track a source of 70 or so preloved disks for the price postage a hundred miles away so will go through and cull those.

Defiant1Dave
November 28th, 2011, 03:56 PM
ok... this post sort of boggles me..... since I use dozens of 720k floppies all the time with my 5140's. All you need to do is take an unused 1.4mb disk, and format it in a 5140.... and viola! 720k disks. How many do you need?

Chuck(G)
November 28th, 2011, 04:17 PM
ok... this post sort of boggles me..... since I use dozens of 720k floppies all the time with my 5140's. All you need to do is take an unused 1.4mb disk, and format it in a 5140.... and viola! 720k disks. How many do you need?

Sigh. Please go back and read the entire thread. :rolleyes:

Defiant1Dave
November 28th, 2011, 04:46 PM
I did read the entire thread, and it still boggles me. Long term stability is not really a problem with 720k disks, regardless of the disk type..... at least in my experience. DS2D and DS/HD both function well when formatted at the lower 720k density in my IBM drives. In fact, I have used both types interchangably for quite a few years now without any significant failures beyond normal wear. They seem to me to be at least as reliable as 5.25" 360k disks.

This is NOT the case when dealing with 1.4mb formatted disks, which do have rather poor reliability. Inevitably, if I have a 3.5" disk failure, it's a 1.4mb disk.... and it fails when containing important data. The OTHER problem that I run into is when trying to reformat used disks from 1.4mb to 720k. That doesn't seem to work very well.

Chuck(G)
November 28th, 2011, 05:08 PM
DD, do you understand the difference in media characteristics of HD and 2D floppies? They're not the same. Using HD media in a 2D drive is not a sound idea.

I can point you to some numbers, if you're still in the dark.

Defiant1Dave
November 28th, 2011, 05:51 PM
Chuck.... of course I know the difference.... and there's no need for the patronizing tone. I've probably been doing this for as long or longer than you have, and had almost a decade in the 1980's of working in Boca Raton on just these issues. I simply think you are incorrect, or you are repeating a published article that was incorrect when it was written.

Yes, they ARE different, but when using them with 720k, it's not a problem. The HD disks are higher density, with smaller particle sizes to accomodate the 1.4mb drive density...... not visa-versa. I would say that using a 2D floppy in an HD drive is problematic, but your statement "Using HD media in a 2D drive is not a sound idea." is simply incorrect. If anything, using HD media in a 2D drive will result in better data stability due to it's higher flux density.

AND practical experience in the real world also indicates this to be true. My 20+ year old 720k disks, written onto HD media certainly bears this out.

mbbrutman
November 28th, 2011, 06:21 PM
Sorry Dave - you are mistaken about the differences.

Double density media and high density media have different recording requirements and the formulation is different. Double density disks require 300 oersteds of force to write while high density disks require 600 oersteds. Double density diskettes use iron oxide while high density disks mix in some cobalt. Using the wrong media results in either a weak magnetic imprint that doesn't last (or is not readable) or damaging the media because too much force was used.

See this article for details: http://en.wikipedia.org/wiki/Floppy_disk



Mike

MikeS
November 28th, 2011, 07:06 PM
Chuck.... of course I know the difference.... and there's no need for the patronizing tone.Actually I kinda felt that your original post had the patronizing tone...

Chuck's the last guy I'd want to argue with about diskettes ;-) But you do say that it's only "in your experience"; can't argue with that, but your experience is not necessarily a universal truth.

The one thing we do all seem to agree on is that like the 5 1/4 disks it's a bad idea to mix formats on the same diskette.

MikeS
November 28th, 2011, 07:11 PM
...Not long ago, I checked with Athana for a customer who wanted thousands of DS2Ds. Athana responded by saying that nobody made them or was likely to make them and good luck with the floppydisk.com people.Ya shoulda asked me; I picked up a few hundred boxed NOS a year or so ago and there were several thousand more available, but although people are always complaining about their scarcity when I offered them here and elsewhere for around $20/50 only two people asked about them, so I ended up giving a bunch away to club members and let the rest go to landfill or wherever.

Chuck(G)
November 28th, 2011, 07:25 PM
Chuck.... of course I know the difference.... and there's no need for the patronizing tone. I've probably been doing this for as long or longer than you have, and had almost a decade in the 1980's of working in Boca Raton on just these issues. I simply think you are incorrect, or you are repeating a published article that was incorrect when it was written.

Please, that's insulting. I started my work with 8" disks in the 1970s. My material comes from NML--back in the 90s, I had a long discussion with a few of their people--who know more about magnetic recording than I'll ever know. If you've perused any of my earlier statements, you'll find that I've said exactly what you've observed--and added that the coating thickness and loading differs between the two media.


If anything, using HD media in a 2D drive will result in better data stability due to it's higher flux density.

If all things were the same in both cases, I'd agree with you.

I'm willing to admit that I'm wrong, but I'll need some authoritative source. Why not contact the NML (http://www.imation.com/en-us/Imation-Products/Imation-Services/Government-Services/NML-RD-Facility/) and see what they think? I'll go along with whatever they say.

Caluser2000
November 28th, 2011, 08:06 PM
Goodness me I didn't mean the thread to turn into a slanging match. Just for the record I've accessed around 20 of the 720k disks and there seems to be no issues with any of them all. Considering they are 1992/3 mag cover disks produced in the thousands I'd say that's pretty good going. The best thing is they cost nothing and relived some early 90s moments playing TIM along with a whole host of other games.

Normal broardcasting will resume shortly.............................;)

Defiant1Dave
November 29th, 2011, 02:43 PM
actually Caluser.... normal broadcasting will probably not resume shortly. There's a bit too much of the "big fish in a little pond" and/or self proclaimed experts around here for me to stay. Gggeeezzz. I'm outa here.

For the record, you might want to talk to IBM. We exhaustively tested HD media in the 720k drives, and found them to be "without issue". I should know.... I wrote the report in 1987. I'm sure it's in their archives.

Ole Juul
November 29th, 2011, 08:35 PM
. . . For the record, you might want to talk to IBM. We exhaustively tested HD media in the 720k drives, and found them to be "without issue". I should know.... I wrote the report in 1987. I'm sure it's in their archives.

I'm just a little fish and not such a strong swimmer. :) So, I wasn't able to find the report you mention. It would be really useful, and a great contribution, if you would be so kind as to post a link for us. Thanks. :)

Caluser2000
November 29th, 2011, 09:31 PM
Actually that's not a bad idea and could probably be stickied for future reference.