ISO Intertec 5.25" floppy drive jumper settings

Adrian Graham binarydinosaurs at
Sun Dec 2 18:38:37 CST 2018

> On 3 Dec 2018, at 00:22, Fred Cisin via cctalk <cctalk at> wrote:
>>> When they went to 400K 40 cylinder MFM DSDD / double sided, double density, still 48 tpi (like the PC-DOS 360K), they chose to call that "QD" / "QUAD DENSITY"!! ?!??  (equating "density" with capacity) WHOA! Everybody else called THAT DSDD "Double Sided Double Density", and used "QD" / "Quad Density" to refer to 80 cylinder Double density 96tpi!
> On Mon, 3 Dec 2018, Adrian Graham via cctalk wrote:
>> So I’ve been reading :) I’m sure they weren’t doing it deliberately, hahaha.
> It's hard to say.  At NCC, at the Intertec booth, they could not understand WHY anybody would want to transfer files between disk formats, other than to PIRATE their "proprietary software"!  They even threatened to sue me if I included it in XenoCopy!
> So, they were not heavy into interoperability with other brands.

Was any manufacturer? I does seem to me that everyone deliberately made their CP/M format different despite using the same or similar chipsets. I was surprised to read in the docs for my Osborne Executive that it COULD read a couple of other formats.

> That was the first time that I added a format to XenoCopy while in a hotel room.  (Televideo was the second!).  NCC was great.  In addition to those two formats, in exchange for buying him lunch, John Draper told me everything that I needed to know to add UCSD P-System formats - (I did NOT exercise with him.) Intertec did not keep their promise - I could have used the free ink.

What machine were you using for hotel room coding?

> One more caveat!  Radio Shack repurposed pin 32 (SIDE SELECT) to use as their fourth drive select, and did their drive select with their cable, rather than the jumpers.  So did IBM, although they jumpered both drives as second drive, rather than ALL jumpered as RS had done.  IBM also used them, as well as the TM100-2 (DS), so there are a LOT of sources for the manuals.

This pair are jumpered as I’d expect, DS0 and 1 with a terminator block. The manual says they’ll work with multi-hole floppies so I’ll strip them down later and give them a good clean.

Owner of Binary Dinosaurs, the UK's biggest private home computer collection?
t: @binarydinosaurs    f:

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