[Intel-devsys] Progress

Herb Johnson hjohnson at retrotechnology.com
Thu Aug 22 21:23:01 MDT 2019

Bill, I'd suggest working with a 5.25-inch drive first, say an old 360K 
DD drive. The board should expect that. The board ought to work with its 
own BIOS but it's possible you need some driver, especially for SCSI 
hard drives. There ought to be an adaptec manual around the Web...


Hey, they are still in business!

Get 360K working, then go for the 8-inch stuff. Dunfield's site 
describes the cabling. You know the drill. There's Richard Main's 
adapter board, right? Or spend $47 and get Dbit's take on the cabling: 
he has a means to fake the GT47 (reduced write current) signal by 
counting seeks:


Dave Wilson of Dbit is a good PDP-11 guy, by the way.


On 8/22/2019 3:57 PM, Bill Beech (NJ7P) wrote:
> All,
> I have been trying to get an device built to use the Dunfield code.  I 
> have the AH-1522A board installed and one 3.5-inch drive attached.  I 
> have turned off the internal disk controller in BIOS.  When the system 
> is booted, it homes the 3.5-inch drive. Placing a a formatted 3.5-inch 
> disk in does not work.  I am going to see what drivers are in place for 
> the FDC.  The Adapted BIOS is loaded in the boot up sequence.
> I need to build one of the 235 disk adapters to test it.  I have not 
> completed the 202 IFC that Jon needs in Eagle.
> As you can see, I have a lot on the plate.
> Thanks!
> Bill 
Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net

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