Prototype IBM DemiDiskette drive

[Tom Gardner]

It was the SA200 a 2/3rds height (51 mm) 5¼-inch FDD at $118 in quantities of 5,000 or more.  It was sold in 1982 but got killed by the true ½ 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
> wrote:

> I just picked up a Model 350 on eBay, just because I'd never seen a 
> Shugart sub 5" drive.
>

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.