[Coco] Drivewire client for OS9/68K

Joel Ewy jcewy at swbell.net
Mon Aug 30 20:59:41 EDT 2010

On 08/29/2010 09:29 PM, Bob Devries wrote:
> Hi Joel,
> I'd guess that a DW client for OS9/68K would involve merging parts of 
> the serial driver such as SC68681 and a hard disk driver (I have 
> source for 2 of those, and the sc68681), and then add the special 
> commands for DW.

Is that the way it's done on the CoCo?  What part of the disk driver 
would need to be in there?  I need to look at the source.

Also, regarding hardware flow control on the 68681 ports -- DW on the 
CoCo is done on the bitbanger port, so no hardware flow control there.  
I'm guessing that interrupts are masked quite a bit of the time.  Maybe 
the MM/1 could bit-bang with one of the parallel port lines -- it might 
even be faster than the UARTs...

> BTW, I need to hack the clock chip on my IO board; the battery in the 
> clock module is now dead. I have seen some info on how to connect an 
> external battery to one of these. I don't have a lot to lose if I try it.

I've got a rail or two of those Dallas clock chips, unused.  But the 
batteries in them are just as old as yours.  ISTR that those Dallas 
chips use a compatible pinout to that Motorola RTC that doesn't have a 
battery.  I wonder if you could pull the clock out of an old '286 or 
'386 PC motherboard, bend a couple pins out, and strap a battery on the 
back of it...


> ----- Original Message ----- From: "Joel Ewy" <jcewy at swbell.net>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Saturday, August 28, 2010 12:22 PM
> Subject: Re: [Coco] Drivewire client for OS9/68K
>> On 08/27/2010 07:56 PM, Bob Devries wrote:
>>> Hi all,
>>> what are the chances of a drivewire client being built for 
>>> OS9/68000? The (extended) MM/1 is well endowed with serial ports via 
>>> the 68070, 68901 and 68681 chips. I'm sure they'd be capable of the 
>>> speek necessary.
>> Bob, you and I may be the only two people on this list who still have 
>> working MM/1 systems (though I'd love to be proven wrong) and I need 
>> to put a 'new' hard drive in mine.  Fortunately I have a small supply 
>> of SCSI drives from old Macs.  I really need to figure out how to use 
>> a SCSI ZIP drive on the MM/1 though, so I have some reasonable way to 
>> back it up... But Drivewire would really help that situation as 
>> well.  I would love to have a DW client for the MM/1.
>>> I notics that it is no longer possible to browse the source tree of 
>>> NitrOS9; else I'd have a go myself at trying to build a 68K version.
>> Time permitting, I'd be willing to help in the porting effort.  My 
>> experience in 68000 assembler is limited to a few exercises in a 
>> class about 20 years ago, and my C is only marginally better by most 
>> reasonable standards, but there's some motivation to learn.
>> JCE
>>> Regards, Bob Devries
>>> Dalby, QLD, Australia
>>> -- 
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>>> one's native tongue is the most vital asset of a competent programmer.
>>> Edsger W.Dijkstra, 18 June 1975
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