On Wed, 22 Aug 2018, Chuck Guzis via cctalk wrote: Well, that was a significant part of the "shirt pocket disk" arguments. George Morrow said, "Why don't we just negotiate with the garment industry to make shirt pockets five and a quarter inches?" 3" (Amstrad) and 3.5" (Sony) made it to market. The Demi-Diskette never made it to market. The 3.25" ALMOST made it to market. It was used on the "Seequa Chameleon 325". So technically, it made it to market. Dysan (3.25") did not want to go with a hard shell. The 3.25" had a metal center hub, but was the same jacket material as 5.25 and 8 inch. Besides shirt pocket dimensions, Dysan reasoned that the winner would be the one that had software availability. So, they bet the company (literally) on software publishing in 3.25". For a brief time, you could have purchased most of the major software packages on 3.25" disk! Dysan software publishing had more titles than Lifeboat. When that did NOT win the war, Dysan never really recovered. The 3.25" drives and diskettes that I have came from MicroPro (Wordstar). -- Grumpy Ol' Fred cisin at xenosoft.com

On 8/22/18 11:41 AM, Chuck Guzis via cctalk wrote: if you google around there is an FTC complaint filed by Tandon about the Shugart Ventures drives. I just picked up a Model 350 on eBay, just because I'd never seen a Shugart sub 5" drive. https://www.ebay.com/itm/Vintage-Sankyo-Shugart-Venture-Model-350-Computer-…

Interesting. I wonder if IBM was looking at those drives for use. The seller (or more accurately the seller's father) used to work for IBM Industrial services in Boca Raton. -Ali

On Wed, Aug 22, 2018 at 1:09 PM, Al Kossow via cctalk <cctalk at classiccmp.org Unfortunately I don't recall the model number, but there was a Shugart 5 1/4" drive that made it at least to prototype and field test around late 1980 or early 1981. It was supposed to be really inexpensive, but almost plug-compatible with standard drives like the SA400. Unlike the SA390, it did have electronics. Instead of being built on an aluminum casting, it only had bent metal. The head stepping mechanism worked like an 8-track tape. It used a solenoid to advance one track inward; the only way to go outward was the next step from the innermost track returned to the outermost (track 0). The single track step time was incredibly slow; I think it was around 750ms, vs 40ms for an SA400. My employer at the time, Apparat, then famous for NewDOS-80 for the TRS-80, had one for evaluation, but decided not to resell them. It would have required special software support, which Apparat could have put in NewDOS-80. Presumably patches could have been offered for other TRS-80 operating systems. I wasn't told what the retail price of the drive would have been, but I don't think it would have sold well even at 1/4 the price of an SA400.

On Wed, 22 Aug 2018, Eric Smith via cctalk wrote: Neat! That could have given Exatron Stringy Floppy a run for the money! Both in terms of CHEAP ("race to the bottom"), low-speed, and probably reliability. Are you sure that that was 750ms track to track step, not 75ms? There were a few 128K machines then. Easiest patches to get around the ridiculously slow speed (going from track 17 (TRS-DOS directory) to track 16 would require 750ms per track to 34 or 39, recalibrate (seek to 0, probably LESS than 750ms) and step 750ms per track from 0 to 16) would have been to cache a dozen tracks, particularly directory, in RAM. 'Course those opting for 128K would also spend the premium for a half-decent drive, . . . It would also argue for the track 0 directory (PC-DOS, Mac, etc.) V the "seek center" track 17 of TRS-DOS, etc. I wonder why Radio Shack didn't consider THAT for the CoCo? They did everything else they could to sabotage it into being a home kids machine and avoid it being usable for anything further. (chiclets keyboard, RF without composite video, 32 characters per line, . . . some of which could be fixed) You will recall that the use of the QumeTrak 142 drive in "PortablePC" (5155) and PCJr required a change in PC-DOS 2.00 to 2.10 for slower step time. -- Grumpy Ol' Fred cisin at xenosoft.com

It was the SA200 a 2/3rds height (51 mm) 5?-inch FDD at $118 in quantities of 5,000 or more. It was sold in 1982 but got killed by the true ? heights which Shugart OEMed from Matsushita. Tom -----Original Message----- From: Eric Smith [mailto:spacewar at gmail.com] Sent: Wednesday, August 22, 2018 1:32 PM To: Al Kossow; General Discussion: On-Topic and Off-Topic Posts Subject: Re: Prototype IBM DemiDiskette drive On Wed, Aug 22, 2018 at 1:09 PM, Al Kossow via cctalk <cctalk at classiccmp.org Unfortunately I don't recall the model number, but there was a Shugart 5 1/4" drive that made it at least to prototype and field test around late 1980 or early 1981. It was supposed to be really inexpensive, but almost plug-compatible with standard drives like the SA400. Unlike the SA390, it did have electronics. Instead of being built on an aluminum casting, it only had bent metal. The head stepping mechanism worked like an 8-track tape. It used a solenoid to advance one track inward; the only way to go outward was the next step from the innermost track returned to the outermost (track 0). The single track step time was incredibly slow; I think it was around 750ms, vs 40ms for an SA400. My employer at the time, Apparat, then famous for NewDOS-80 for the TRS-80, had one for evaluation, but decided not to resell them. It would have required special software support, which Apparat could have put in NewDOS-80. Presumably patches could have been offered for other TRS-80 operating systems. I wasn't told what the retail price of the drive would have been, but I don't think it would have sold well even at 1/4 the price of an SA400.