- ... Reading through this thread, one thing that occurred to me is that you might want to check the step rate that you re running to ensure it isn t too fastMessage 1 of 40 , Nov 25, 2012View SourceOn 11/25/2012 06:05 PM, Richard Cini wrote:
> Would you mind sending me a copy of your CBIOS off-list? I would like toReading through this thread, one thing that occurred to me is that you
> compare the 8272 register configuration and setup to mine.
might want to check the step rate that you're running to ensure it isn't
too fast for the drive. I had exactly this problem...oh...almost 30
years ago. I have no idea how I remember that. ;)
Dave McGuire, AK4HZ
New Kensington, PA
- ... Here s the service manual for the Tandom TM-848, with the schematics in the back: http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdfMessage 40 of 40 , Dec 15, 2012View SourceOn Sat, 15 Dec 2012, joshbensadon wrote:
> --- In email@example.com, Mike Loewen <mloewen@...> wrote:Here's the service manual for the Tandom TM-848, with the schematics in
>> The double-sided drives have a 2S signal on pin 10 of the interface
>> connector to indicate single or double-sided media. The outputs of the
>> respective pulse-shaping ciruitry for each sensor is essentially ORed to
>> form a single Index pulse output.
> Cool, so I can imagine the two sensor signals going to an RS flip flop
> to provide the 2S signal and as you said to an OR gate for the index.
Knock yourself out. :-)
> Hmm, thinking about why, I guess the design was to create a hardwareThe 5.25" drives only had a single index hole aperture.
> error if a user placed a DS disk into a SS drive. As Rich found, the
> lack of index pulses caused a drive not ready. Correct me if I'm wrong,
> but in later 5.25" drives, they did not change the index sensor
> location. Then I suppose the errors created would be software
> I vaguely remember hearing a discussion about how computers switchedI couldn't say. Certainly Woz did a lot in software for his Apple II
> from hardware solutions to software solutions, then back to hardware.
> I just don't know the dates, could this 8" to 5.25" be part of that
disk controller design. Another odd thing about the 8" drivers vs the
5-1/4" drives was that the 8" drives had a write-enable notch, while the
5-1/4: drives had a write-protect notch. Very confusing.
Mike Loewen mloewen@...
Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/