rasz_pl wrote on 2024-01-28, 20:52:

Everybody knows about 3.5 inch HD 1.44MB floppies, first introduced in 1985 by NEC inside PC-8801 mkII MR. West first heard abou […]
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Everybody knows about 3.5 inch HD 1.44MB floppies, first introduced in 1985 by NEC inside PC-8801 mkII MR. West first heard about them from 10 November 1986 InfoWorld "Vendor Introduces Ultra High-Density Floppy Disk Media" https://books.google.com/books?id=rDwEAAAAMBAJ&pg=PA19 IBM followed in 1997 switching PS/2 to 2HD floppies, Apple in 1988. 80 tracks ~50KB/s speed.

Much less known is ED 2.88MB. Only ever shipped in some 1990 IBM PS/2 and NEXT computers. 80 tracks ~100KB/s speed.

But pretty much nobody outside of Japan has ever hear about 'Triple' or '2TD' format developed and shipped by NEC inside PC-88 VA3 in 1988. 13MB unformatted, 9MB formatted capacity!! Triple because it tripled track density from 80 to 240 while reusing ED barium ferrite magnetic media, same ~100KB/s speed.

The best (only) document describing this format is NEC uPD72070 floppy controller documentation, curiously stored under apple/sony at bitsavers http://bitsavers.informatik.uni-stuttgart.de/ … cation_1991.pdf Simplicity of the design suggests any ED capable (1Mbit bitrate) controller should work out of the box with Triple floppy drive.

Has anyone ever seen 2TD floppy drive in the wild?

Very intriguing. I'm pretty sure I was never aware this format even existed.
Most 2.88MB drives were shipped with some certain IBM PCs (these were not compatible with standard PCs due to having a different pinout (which usually was the power going through the 34p ribbon cable and omitting the separate 4p power connector)), but there were some 2.88MB drives which did end up in a PC or 2. But it was extremely uncommon (iirc out of all the hundreds of PCs I seen, I think I seen the 2.88MB drive installed in a PC only once). During the P2/P3 era I frequented a lot of PC stores and I don't think most people working there had ever even heard of the 2.88MB floppy drive.

And I've never ever heard of this TD floppy drive format.
I haven't read the entire document, but it gave me the impression it was a standard type of floppy drive and not some kind of floptical design?

Would be nice to have some model numbers of such floppy drives.

I'm sorry I can't give you any new information about this format. It would be nice to have some more info about it.

I don't think I've ever seen a PC with the option for supporting such TD floppy drives, so even if you have the drive and media, I presume it would be difficult finding any kind of practical use for it.

One of my PCCHIPS motherboards supported a 1mb floppy transfer rate, never knew why.

Its unfortunate 2.88mb floppies weren’t released a year earlier , as it was 1.44 were commoditized and 2.88 were extremely expensive.
If someone big would have bit the bullet and went all in 2.88mb only on every machine (maybe Apple or IBM) early you may have forced the industry forward.
Next The 2.88mb media had the same problem as 1.2mb media in that it couldn’t be formatted for a lower density (1.44) and reliability used in a 1.44 drive. It’s unfortunate we never standardized between formats better

This meant a chicken and egg, if a 1.44 was $35 and good enough
why pay $200+ for 2.8?
If no one pays to play nobody supports the format and the disks never get driven down in price.

Then CDROMs got popular making it so 1.44 was good enough for a document or a little pic and could be mass produced for pennies so why bother with the larger drive.

Was extremely unfortunate timing , back in the day there were daily occurrences for me that a 2.88 floppy would have simplified (like not having to make a spanned zip file)

Tetrium wrote on 2024-01-29, 15:49:

I don't think I've ever seen a PC with the option for supporting such TD floppy drives, so even if you have the drive and media, I presume it would be difficult finding any kind of practical use for it.

It should work on any ED controller. For example Adaptec AHA-1542 (N82077SL/PC8477 full ED support) should have no problem driving it. Most chipsets/superIOs from Pentium era forward has 1Mbit support because everyone expected switch to 2.88MB drives after IBM shipped some in 1990.

rmay635703 wrote on 2024-01-29, 17:08:

The 2.88mb media had the same problem as 1.2mb media in that it couldn’t be formatted for a lower density (1.44) and reliability used in a 1.44 drive. It’s unfortunate we never standardized between formats better

Im pretty sure all ED floppy drives have dual PMR/LMR heads, when formatting HD 1.44MB LMR head is being used. As long as Bios supports ED it would at least allow booting TD floppy disk, then its just a matter of DOS realizing it can go above track 80 all the way to 240.

rmay635703 wrote on 2024-01-29, 17:08:

This meant a chicken and egg, if a 1.44 was $35 and good enough
why pay $200+ for 2.8?
If no one pays to play nobody supports the format and the disks never get driven down in price.

Prices go down. When HD floppies were first announced in US in that 1986 InfoWorld "Vendor Introduces Ultra High-Density Floppy Disk Media" article listed $6-7 OEM $12-15 retail per one HD floppy disk, that didnt last long 😀

There is this fantastic "Oral History of Jugi Tandon" Computer History Museum https://www.youtube.com/watch?v=hf7RK8xYwG8 video where Jugi (absolute legend) talks how floppy drive heads cost $50 a pop in 1975-76. He came in saying this is unsustainable, if I sell $50 heads my clients will go out of business and I lose sales, so he started making $15 head + carriage combos 😀 then switched to whole drives in 1977 because he couldnt stand how expensive and inefficient his drive making clients were.

Hayes, Thomas C. (July 25, 1983). "Tandon rides computer crest". New York Times https://www.nytimes.com/1983/07/25/business/t … uter-crest.html :
"Mr. Tandon repeatedly has confounded rivals and delighted customers by lowering prices sometimes as far as two years in advance of delivery, undercutting competitors. His disk drives now range from $50 to $1,000."
Tandon TM-100-2 drive can be found in old PC Mag classifieds listed retail $100 (means $50 bulk oem) while Commodore 1541 was over $300. Commodore was selling 1541 for more than C64 + Tandon TM-100-2.

Epson started making SD-560 5.25" 1.2MB HD drive in 1983! In 1985 it was selling for $95 https://archive.org/details/bitsavers_fujitsu … heater&q=sd-560
3.5" 1.44HD floppy drive in 1985 was $145.

Beauty of Triple floppy drive is its reuse of ED media. Computer shouldnt even notice difference between ED and TD floppy. I also found this curious source claiming you can force ED drive into formatting HD floppy to 2.88MB 😮 https://ardent-tool.com/floppy/floppy.html#2.88_Floppy_Hack
"As a last note, the 1.44MB media seems to work well at 2.88MB. It formats error-free and seems to hold data with no problem. I am doing some long-term testing to see if it will retain data. "

There were other attempts at bigger floppies in Japan. For example 1985 Hitachi FDD541 5.25" storing 4.15MB (6.5MB raw) of data on special Maxell MD2-EH disks. 720 RPM, 104 tracks, 3750 Kbit RLL 2,7 encoding (like RLL hard drives) using RLL ST506 HD controller. Problem with this drive was usage of expensive for 1985 dedicated HDD controller and special unique floppy disks, Im sure 720 rpm didnt help with medium longevity. https://www.hitachihyoron.com/jp/pdf/1985/01/1985_01_06.pdf

rmay635703 wrote on 2024-01-29, 17:08:

Then CDROMs got popular making it so 1.44 was good enough for a document or a little pic and could be mass produced for pennies so why bother with the larger drive.

This is what makes that Triple drive in 1988 NEC PC-88 VA3 so insane. With 9MB floppies, probably 10.5-11MB with something like Microsofts Distribution Media Format, CDs wouldnt be that critical for early software distribution. Amiga 11 floppy Return to Monkey Island is one such meme, but Beneath a Steel Sky came on 15 Amiga floppies 😀 and still 6 HD floppies on PC. In alternate reality it could have shipped on 1 TD disk with space to spare 😀