[Coco] DriveWire issues with Coco 1 F/285 Board

[Luis Antoniosi (CoCoDemus)]

I run on a slow computer too, it's a netbook asus acer one with windows
starter too :P


On Tue, Jul 2, 2013 at 4:43 PM, Aaron Wolfe <aawolfe at gmail.com> wrote:

> On Tue, Jul 2, 2013 at 11:20 AM, Luis Antoniosi (CoCoDemus)
> <retrocanada76 at gmail.com> wrote:
> > Hi I already tested the DSK you sent me. Also I use an hdbdos built from
> > toolshed.
> >
> > My problem seems to be on Drivewire server side. I need to set:
> ReadDelay =
> > 1 and WriteByteDelay = 0 to have it properly working.
> >
> > I don't know about the speed cause i've never seem it running on a coco1
> > but it seems to run fine now.
> >
> > Could it be related to the USB dongle I'm using is unknown, one thing is
> > for sure: my DriveWire is pretty unstable even with coco2 or 3. Often it
> > will get error reading and I need to restart the DW.
> >
>
> If this is a problem with your 741C then I am a bit surprised that
> ReadDelay = 1 helps. That is creating an artificial 1 ms delay in only
> one specific operation: between reading 4 bytes from the coco
> requesting a disk sector and returning that sector's data to the coco.
>  It can often take > 1ms just to fetch the disk sector, especially in
> the case of remote images.  I use ReadDelay to simulate this and
> usually set it to 200 or 300 :)
>
> I would think that if the 741 is too slow to operate reliably at X
> bps, then delaying it only at one specific point in a long transaction
> would not improve things... right?
>
> One difference between DW3 and DW4 is that DW4 will cache images in
> RAM when possible.  Maybe this means that when the sector data is
> already in ram, DW4 returns it so fast that the CoCo 1 needs a little
> breathing room that wasn't necessary under DW3?  Adding only 1ms per
> sector really isn't terrible (I wouldn't think?), so maybe that's just
> how it is on some CoCo 1.
>
> I would certainly try an alternate usb-serial adapter if possible.
> You should also take a look at the adapter's settings.  Most have
> several adjustments available for how they buffer, how often they poll
> the usb bus, etc. Many FTDI adapters come with default settings that
> are completely wrong for the type of communications that DW does.
>
> Here is a video showing how to get ~30% faster performance with an
> FTDI adapter.  These same type of settings might be the key to making
> your adapter happy, I don't know.
>
> http://www.youtube.com/watch?v=P8Ehm-J0LAA
>
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>



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