RT-11 doesn't recognize my 3.5" floppy

Charles charlesmorris800 at centurytel.net
Wed May 8 12:27:25 CDT 2019

On 06/05/2019 23:38, John Forecast via cctalk wrote:
> The release notes on bitsavers indicate that the RX33 was not supported 
> until RT-11 V5.04.

>> On May 6, 2019, at 6:20 PM, Charles via cctalk <cctalk at classiccmp.org> 
>> wrote:
>> I have installed an RQDX3

>> But, when I boot the system (with RT-11SJ V5.01), it can't see the drive 
>> at all.

Not only was the RX33 not supported until 5.04, there's a bug in the
MSCP DU driver that wasn't fixed until 5.03 (IIRC) or maybe 5.04, which
means nothing on an RQDX3 can be guaranteed to work properly before
that.  It caused me a lot of grief, way back in 1994.

See the files at http://www.dunnington.info/public/RQDX/ and
particularly http://www.dunnington.info/public/RQDX/DUX.TXT if you're

Pete Turnbull
thanks for the additional info. Will check out the links.

Meanwhile, I found an RK05 image of RT-11 "5.4" on bitsavers, made an RL02 
bootable -SJ image on SIMH, then copied it over to the hardware with 
(I didn't have to wait for the entire 10 MB since the contents were all on 
the first 3 MB anyway and no bad blocks).
The system booted up to a 5.04 prompt and DU0: is fully usable with 2382 
blocks on a 3.5" diskette :)

My TSX+ 6.50 copy also didn't have DU enabled in TSGEN.MAC so I had to 
uncomment that DEVDEF line and reassemble/relink. It's SLOW on my 11/23+... 
we're spoiled with GHz PC's and GB of RAM.
Now I can use the floppy under TSX+ too.

But the generic 3.5" drive in my WinXP box can't successfully emulate an 
3.5" RX33 with PUTR, apparently. (Nor an RX23).
I only get read/write/directory errors after several seconds of head 
activity even with /RX33 and /RT11 switches set.
Time for more reading and maybe drive swapping/tweaking...

More information about the cctalk mailing list