[Coco] Preserving old CoCo diskettes...

[Mark Marlette]

Gene,

Read the errata on the 6551. This has been discussed before. You decide. I know what your conclusion will be....You already said it.

Regards,

Mark
Cloud-9


----- Original Message -----
From: "Gene Heskett" <gene.heskett at verizon.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Monday, May 17, 2010 11:04:15 PM
Subject: Re: [Coco] Preserving old CoCo diskettes...

On Monday 17 May 2010, Allen Huffman wrote:
>My problem:
>
>I have HUNDREDS of floppy disks from my CoCo. Some are standard 35-track,
> some are 40 track, and some are OS-9.
>
>I want to get these all backed up, but things like HDB-DOS only deal with
> 35-track disks, so I have never been able to back up my data (including
> things like hidden DOS commands to set up 40 tracks, 6ms, etc.).
>
>So, a few years ago, I wrote software to write sectors across a serial port
> (under OS-9) and would insert a disk and just stream the disk to the other
> side, where it would be written out as a raw disk image of sectors. (I
> think I actually used this to transfer an entire 128MB hard drive over!)
>
>Someone has bound to have already faced this and worked up a better
> solution.
>
I am doing that yet Allen as its the only way I have to get linux built nos9 
dsk images to my coco as this motherboards chipset apparently doesn't support 
256 byte sector formats.  So I have to zmodem them to the coco, and write 
them with a basic09 program I obviously named dd.  Linux only, here on the 
main floor.

Unfortunately, recent versions of sc6551.dr are not capable to using flow 
controls, eventually hanging the transfer hard.  That restricts me to a 
maximum transfer of 480cps, or 4800 baud.  6809 coco's may not even be able 
to do that, using zmodem.  It may be that ymodem could run much faster, but I 
haven't seriously attempted that as my main experience is with zmodem.  My 
fault of course.

I, and Robert Gould, have spent quite a bit of time with this over the last 
year or so, and I have come to the conclusion that the SC6551 is a drain 
bamaged chip and that the only real cure is a different uart.  However, at 
4800 baud, where no flow controls are needed, its as bullet proof as any.

>Anyone have suggestions? Hooking a 5 1/4" drive up to a computer is not an
> option. I'm running Macs and haven't had anything with a floppy disk on it
> since 1998 :-)

What does that kool-aid taste like?  Apples I'd assume. ;-)

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-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
What fools these morals be!

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