[Coco] IDE interfaces

Gene Heskett gheskett at wdtv.com
Tue Mar 15 09:04:17 EDT 2016

On Tuesday 15 March 2016 04:16:51 Tormod Volden wrote:

> On Tue, Mar 15, 2016 at 7:09 AM, Doug Fraser wrote:
> > I'm looking for an IDE interface to replace my Burke n Burke
> > adapter. Does anyone know where I can acquire one?
> At least a while ago there were still Glenside IDE boards to be had.
> They are supported by HDB-DOS and NitrOS-9.
> If there are no boards left we should try to have more made. Maybe
> somebody is working on it, because request about schematics come up
> from time to time.
> Regards,
> Tormod

Lets look at reality Tormod.  And that is that if new boards are made, 
they should be designed to handle sata drives simply because that is all 
we can buy today. Anything we can pick up at a flea market today, quite 
likely has had its 50,000 hours of spin time and isat best using a cane 
to get around like I am.

I think possibly a few dollars more expensive because that likely would 
have to have not only the interface chip, but there would need to be a 
fpga translation and buffer memory just to bridge the gap between bus 
speeds.  Current sata drives can move data at 6GB/second, so seek time 
is the random access speed limiter but at the coco's speed that is a 
total non-issue.

Physical sector sizes are presently at 4096 bytes a sector in new 
rotating media, and I've heard rumors that there are drives with 32768 
sector sizes on the horizon, so a new interface would have to translate 
that into a 256 byte sector slices for the coco. We already do the 
512/256 translation in the drivers, but IMO that really belongs in the 
controller, which with modern hardware could handle that in 64 to 256 
byte wide pieces per machine cycle of its hardware.

Or am I dreaming?  The only seemingly future-proof interface, scsi, has 
been rendered obsolete by lack of new drives in the pipelines.  And now 
ide/atapi  stuff is a minimum of 15 years old.  And with its 
unterminated interfaces restricting cable lengths to nominally 15 to 18 
inches, which finally did get some impedance matching about the time the 
80 wire cable showed up, but done so poorly that its like a pig, no 
matter how much lipstick you put on it, its STILL a pig.

I was initially spooky about sata, but so far, the only problems I have 
had with it have been that "hot red" cabling supplied by about 99% of 
the vendors.

That particular dye in a cables insulation has been known as a time bomb 
by me from back in the early 70's when it became populer in CB radio 
microphone cable, it slowly turns the copper conductor its wrapped 
around into a copper oxide powder, a very poor conductor. Takes from 3 
to 5 years to fail.  Replace them with any other color of cable and 
you'll have no further problems with your sata stuffs.

This machine, with 6 sata ports in its motherboard, has had the red ones 
I built it with nearly a decade ago all replaced with some other color, 
and I can go poking around it its internals now without blasting the 
system log with 100k of sata reset messages because the red cable is 
crap after a few years.

My $0.02.

Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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