[Coco] Ebay 190089697152 RS Tandy TRS-80 Disk/Video Interface

[wdg3rd at comcast.net]

From: "Chester A Patterson" <vchester at setec-cr.com>

> Ebay 190089697152 RS Tandy TRS-80 Disk/Video Interface
> I've never seen anything like this! Looks like a Coco floppy disk
> controller. Other than being a very large dual 5.25" floppy unit, what
> could the video interface business be about? /Chester

The TRS-80 Disk/Video Interface allows a TRS-80 Model 100 (or 102) portable computer to connect via its bus connector to one (as shipped) or two (never seen it done myself) 5.25" floppy drives and to an external display, either TV or composite monitor.  This allowed faster storage than the cassette interface and more text than the built-in 40x8 LCD could show.  Display was 40x25 or 80x25 (80x25 on a TV is, as expected, quite ugly).

In essence, it was the first ever docking station on the market for a notebook computer.  The biggest flaw was the fragility of the connection to the system bus, which was basically a ROM socket.  The DVI came with a ZIF socket extension to plug into the bus connector.  The pins on the cable still broke with annoying (and expensive) frequency.  The biggest improvement that came in with the Model 102 was the change of the bus connector to a header socket.

Radio Shack produced no software to take advantage of the disk or display, and at this point in time I don't recall any third party offerings.  We didn't sell all that many of them.  I have one that I haven't taken out of its box in most of a decade.  Easier to null-modem the data to another machine and play with it there.
-- 
Ward Griffiths    wdg3rd at comcast.net

Carjacking or impoundment? We now have two vocabularies for wrongs, depending on whether private persons or government agents commit them. This is the difference between mass murder and national defense. Between extortion and taxation. Between counterfeiting and inflation. And so on. Other examples will occur to the astute reader.   Joseph Sobran