Re: Lobo floppy drives
- --- In firstname.lastname@example.org, Richard Cini <rich.cini@...> wrote:
>I think the 25229 sounds like a Shugart 800/801 board model number.
> Bill --
> I didn't have time to pull both drives tonight but I did unmount the
> left-hand drive. Indeed it's a Shugart 801, SN# HV2633. As far as jumpers,
> DS1, T1, X, B and A are closed. EZ is set to Z. EI jumper is open. The
> 800/801 jumper is also open. There are black-ink markings on the PCB as
> follows: "25229.1", "1932", "48.2". I'll try to pull the other drive
> tomorrow and let you know if it's any different jumper-wise (assuming it's
> set for DS2).
>the DJ2D-B is a decent enough 8-inch controller. Morrow docs are good.
> On a slightly-related note, I have two floppy controllers, a Morrow DJ2B and
> a VersaFloppy II, that I would consider using to build a new floppy system
> from. Is one better than the other for these drives? The Morrow board looks
> like 8"-only while the VF2 has both floppy connector types.
The Versafloppy II is also a decent controller. My Web site has work of half a dozen people with that controller, including John Monahan (s100computers.com).
Either ought to be able to run those Shugart 800's.
- On 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/