Which tapes must I buy for the HP82161A Digital Cassette Drive??


Any you can find! They are one of the hardest things to find. The cassettes don't have any part number on them. The tape drive owner's manual says the box of ten tapes is P/N HP82176A. The cassettes say "Hewlette Packard Mini Data Cassette" and hold 24 meters of tape.


IIRC, they were called HP82176 tapes. They are special, and very hard to find now. AFAIK, no more standard cassette will even fit into the 82161 --certainly the minicassettes and microcassettes sold in the UK don't
fit. I believe Verbatim may have made/sold something similar at one point -- AFAIK the 82161 alignment tape (no, I don't have it) was a Verbatim product, for example.
Another thing to be aware of is that old cassettes can deteriorate with time. Normally the pressure pad fails (and can be rebuilt), but I have had other problems. I wrote an article in Datafile (HPCC journal) last year about this -- I can supply the LaTeX source for it if anyone needs it.


Yes, Verbatim made cassette tapes for usage with the 82161A.
I have two of those cassettes, and some more of the original HP brand tapes, one or two still sealed.
And no, I don't sell them, maybe trading for other interesting HP items could be considered;-)




I bought a box of 10 original HP cassettes unopened on ebay last year. Not for sale but I might consider trades as well. By the way, the cellophane is still on 9 of them.


I know a guy with a huge cache of those things- over 100 boxes. If you want to buy them, I'm sure he would be willing to scalp you to death.



Why bother with tapes. They are slow and you can't get them anynore. Get a 9114A or 9114B floppy drive, they are not particularly expensive (even on eBay :-) and they take standard floppies (provided you mask the Quad density hole).

Also the battery may need rebuilding, there were a number of articles on the HP Forum 1-2 years ago.



While I'll agree that the 9114 is a much more useful unit than the 82161 (it uses easily-available media, it stores about 5 times as much data, the disks can be read/written in a PC),
I do not agree that you can use HD disks in one. Covering the density detection hole won't do a darn thing -- there is no sensor for it in any 9114 (why should there be? The drives were designed long before there were HD disks). But
contrary to popular believe the HD and DD disks are magnetically different, and the 9114 does not use the correct write current for the HD disks. If you value your data, you'll use DD ('720K') disks, which are not hard to find.
The batteries are easy to rebuild. 3 2.5Ah Cyclon cells in series are a perfect fit in the housing.


On both of my 9114 drives, I must cover the hole for modern floppy disks to work... and they work just fine. If you don't cover the hole, the drive will not recognize the disk. I have disks over five years old that still read without error. I have look for regular 720K disks, and have never been able to find any in the last five years. I had a box of 50 that I use with my Toshiba T1000 lap top (you can read the screen in broad day light, and it is slo enough that it can work with some old data acquisition boxes that do not work with modern machines)


You're absolutely right about covering the hole, at least on the 9114A (I can't be bothered to take by B apart tonight). I've just looked at a spare Sony disk drive for the 9114A,
and the disk inserted sensor pin is in just the right place to end up in the HD hole. So the drive will think it has no disk at all if the hole is uncovered.
However, I still won't use them. The coercivity is wrong, period. It may work on some units, it may not be reliable, it may not work at all on others. My data is worth a lot more than that. Over here, 720K disks are easy to obtain (just as well, I have one machine that uses HD disks, and a dozen that use DD ones...)


Tony Duell (UK) wrote:

> I believe Verbatim may have made/sold something similar at one point

Yes, its the VERBATIM MI 80 mini data cassette.

There is one actually for sale on eBay:




Tony Duell (UK) wrote:

> I believe Verbatim may have made/sold something similar at one point

Yes, its the VERBATIM MI 80 mini data cassette.

There is one actually for sale on eBay:




I was going to recommend MEI-Micro Center as a source for 720K diskettes but I found a catalog from some time last year and they have them - only while supplies last.

Regarding the media itself, while I know there is a difference between 5-1/4 inch 360k and 1.2M media, I was under the impression that 3-1/2 inch media (at least 720K and 1.44M)(or 1M and 2M as the makers call them)was at least the same coercivity. My only evidence (other than apparent functionality) is that 360K media was light brown and 1.2M was black, while 720k and 1.44M are both black. I have noticed, however, that if you hold them up to the light, you cannot see through the 720k media, while you can see through the 1.44M.


8 inch, 5 1/4 inch and 720K 3 1/2 inch media are identical and all used either FM or MFM (GCR for some systems eg Commodore and apple I think) which required similar coercivity. FM was single density, and MFM and GCR were double density. Called so because (no surprises here) they could record data at double the linear density. They then doubled the number of tracks and doubled the number of sides. We started at 90k SSSD - 180k SSDD - 360K DSDD to 720K when the number of tracks per inch doubled.

1.44M used a higher coercivity to increase the linear density. That was why the 1.44M disks had an extra hole. I know that many people punched a hole into 720K disks to turn them into 1.44M disks. This was not supposed to work and I read many articles on how this was not supposed to work - but it did - go figure! The theory is that the record level on the 1.44M was too high and if 720K disks were recorded at 1.44M you could not erase them. Although I never did this (I did not want to be arrested by the floppy police) I know a number of people who did.


There is a difference in coercivity between 720K and 1.44M disks. I can't remember the exact values, but they're fairly close, which is why it sometimes works if you use the 'wrong' disk. I still won't do it.
One place you might find 720K disks ia professional music shop (or a place that sells professional audio and video tape). Apparently some synthesisers/samplers (I don't know the details) use them, and can't use 1.44M disks. So they're still sold for those instruments. Probably won't be cheap, but a single disk holds a lot of calculator programs.


If you know anybody in PC support they will probably have hundreds in the form of old software disks.

We have thrown out boxes of disks over the last few years. We keep the 1.44 floppies to reuse.


Quoting: "The theory is that the record level on the 1.44M was too high and if 720K disks were recorded at 1.44M you could not erase them."

You left out the 5-1/4 inch high density (1.2M) format native to the drive that came on the original IBM PC-AT, which I think is the source of the idea quoted above. The problem there was that the high density drive could read and write 360K (IBM PC) disks by using a data rate of 300 kb/s (because the disk spins at 360 RPM, like 8 inch drives) instead of 250 kb/s (for the 360K drive which spins the disk at 300 RPM) AND (importantly) double stepping the 96 tracks/inch head carriage (the 360K drive was 48 tracks/inch). What made this work was that track 0 on both high density and 360K drives was at the same radial distance so track 2 of the 1.2M drive was at the same distance as track 1 of the 360K drive etc. The problem arose when you started moving a diskette between the 1.2M drive and a 360K drive. Because the 1.2M drive only actually wrote on one 96 TPI track, previous 48 TPI data written by a 360K drive would not have been fully erased, so reading the data back on a 360K drive could fail (reading back on a 1.2M would be OK). To reliably move data from a 1.2M drive to a 360K drive, you had to start with a bulk-erased diskette formatted in the 1.2M drive (with a 360K format).

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