Fragile microdrives

[mselkin]

Hi everyone, this may have been asked before, possibly several times. I'm experiencing a repeated phenomenon with microdrive cartridges, where if load a known, working cart, it will work for one or two or more reads and then never load again, reporting the "bad media or media changed error". This is not related to the drive itself as I have observed this behavior on 3 different drives. This behavior is also occurring on newly re-felted drives.

Is this just something I should accept, given the age of these microdrive cartridges'?
Is there anything that can be done to revive those carts that were working fine and then suddenly stopped?

Any comments would be appreciated.

Thanking you,
Mark

[Cristian]

Is this just something I should accept, given the age of these microdrive cartridges'?

Probably yes. Don't forget we're talking about 35+ year old tapes. Who knows how many times they have been written, deleted...

It's a good idea to keep clean the magnetic heads with a cotton earstick and some alcohol. You may try to gently push down the cartridge when running, to keep it more steady...

[NormanDunbar]

Maybe the refelting foam is not the correct kind and is either statically killing the content, or tradhing the physical tape?

Chr$ on here, amongst others, knows about these things and is/was selling the correct felt for a while.

This might help, search.php?keywords=Chr%24+felt.

Cheers,
Norm.

[Chr$]

mselkin has previously had some carts (and felt pieces? can't remember) from me!

So many factors related to mdv reliability, and there are more knowledgeable experts in that respect! Many discussions on here over the years as I'm sure you've seen. I know from recovering data from hundreds of carts that my felt pieces are excellent for data recovery and of all the people that have used them and occasionally use (i.e. read/write to) the carts, feedback as always been good. It's shocking that even when new, most sellers of software on carts would only guarantee the content and replace them if errors occurred, within 3 months from purchase date! So I suppose after 30+ years it must be a miracle when anything loads properly.

Are these old carts with my felt pieces on them? Or the actual NOS carts (originally written to with Psion v1 and never used) from me?

I tend to usually recover the data (with mdump from Daniele) and I think once you have the data as an .mdv image it's probably slightly more reliable in the long run to format the original cartridge a few times and then write the image back on to it, so that you have an exact copy but with the advantage that any degraded sectors are marked as bad by the formatting. Remind me, do you have a vdrive/vmap combo?

With old carts you never know how much use they have had, how worn out they are and also if e.g. previously bits of the old sponge may have already been ingested.

Drives can also be very finicky and often I find it almost impossible to tell if the problems are the drive(s) or the medium.

I have days sometimes when I despair and don't know why I put so much effort into collecting and having anything to do with mdvs! Other days I really dig the whirr and everything seems to work fine.

[mselkin]

Thank you to everyone for your replies.

Chr$, I have had the experience of losing the ability to read the data from both eBay purchases of old original software and from one of the drives I purchased from you. (When that occurred, I stopped using the others, in order to preserve their data until I get my vDrive.)
I was able to finally order a vMap and vDrive, so I hope to be able to save the data on the other carts, when that arrives.

I see no visible wear or any degradation of the foam on the cartridges that have failed. I can fully understand that after all this time, the carts would be unreliable but I seem to experiencing a complete failure of the carts after only loading from them twice. I worried it was my drive itself but I found the same behaviour on an external microdrive plugged into my QL.

[Martin_Head]

As Cristian says. It may be the magnetic coating on the tape disintegrating and leaving deposits on the heads. Think about VHS/Betamax video recorders, when you had an old worn out tape that 'clogged' the video heads.

I would recommend not using any important Microdrive cartridges until you can make a backup onto another medium.

[Chr$]

and from one of the drives I purchased from you. (When that occurred, I stopped using the others, in order to preserve their data until I get my vDrive.)

Use the others from me and see how they go.... don't be afraid to use them, I can always send replacements when I next send you something.

Hopefully the one that is misbehaving is an iffy one that got through my QC. I've had that a few times on those that I've written the PD games to - written fine and then for some reason iffy loading, so I always reject it and do it again with another, when I spot it.

[tofro]

Be aware that, whatever you do (read or write to the mdv), the sector headers on the drives have been written 35 years ago, and never been touched since then (they're only written - or "renewed" when the cartridge is formatted, and are never touched again until the next format). Like anything, the magnetic polarisation on the headers is doomed to vanish into the universe's preference for entropy.

When sector header information is lost, the cartridge is going to become more and more unreadable (because sectors are referenced in the map and cannot be found).

So, in most cases, I think it's the tape that causes problems, not the drives.

[JupiterJones]

Hi everyone, this may have been asked before, possibly several times. I'm experiencing a repeated phenomenon with microdrive cartridges, where if load a known, working cart, it will work for one or two or more reads and then never load again, reporting the "bad media or media changed error". This is not related to the drive itself as I have observed this behavior on 3 different drives. This behavior is also occurring on newly re-felted drives.

Is this just something I should accept, given the age of these microdrive cartridges'?
Is there anything that can be done to revive those carts that were working fine and then suddenly stopped?

Any comments would be appreciated.

Thanking you,
Mark

Hi,

From my more than scarce experience, yes, old mdvs that you don't know who owned it before tend to be really unreliable.

Refelting indeed helps. I only have experience refelting myself with some audio tape felt, it helps but I'm experiencing some unreliability due to the thickness of this felt. Now, I'd probably would go for felts Chr$ sells.

Another factor to take in consideration is your QL's case adjustment. It must close nicely and even in the microdrives area, if not cartridges are slightly above where they should be and also makes working them more unreliable.

This is my experience so far (a couple of weeks...) so if anyone in the forum says you something in another direction, please take their advice before mine!

But hope this helps somehow.

Víctor

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