[Coco] Four slot MPI project

Gene Heskett gheskett at shentel.net
Mon Jul 30 04:14:36 EDT 2018 

On Sunday 29 July 2018 22:47:15 Dave Philipsen wrote:

> A SATA interface is not an easy thing to design or support considering
> that there are no drivers to support it in the 6809 world and that you
> would not see a performance benefit over parallel ATA (in the 6809
> world). There are inexpensive adapters still available (I believe)
> that would do the conversion between parallel ATA (IDE) and SATA which
> would probably be much easier to work with considering that the PATA
> is a much simpler interface for which we already have support for the
> CoCo.  The PATA interface has way more throughput than any CoCo at any
> speed would ever be able to utilize.
>
> The SATA interface is pretty complex and runs at gigabit speeds. I’m
> not saying it can’t be done but I’m not sure the effort would be worth
> it.
>
> Dave

The advantage is readily available for peanuts solid state drives, a 
drive the coco will not wear out in any of our grand children's 
remaining lifetimes. Do you know of a scsi-sata adapter? Sata command 
structure is essentially scsi-II. Once the init has been done at boot 
time, a sata drive and a scsi drive are treated the same by linux. Any 
translations are expected to be done by the hardware. Its only achilles 
heel is the red cables used for 95% of the builds, the red dye eats the 
copper conductor in about 5 years. I've been fighting with that dye 
since it first showed up in the cow barn radios the Japanese sold us a 
few cajillion of back in the 1970's.

That and I do not have a pata adapter as I've never had any great luck 
with pata's, what with its termination problems being even pickier than 
scsi with an si diode as the bus isolator and a sagging 5 volt line from 
the psu, what I have is one of Marks full scsi-II interfaces. Hardware 
wise, it should be a bi-di buffer of decent speeds to from a 6061 memory, 
and a seriel convertor to make sata out of the 8 bit pata. Just borrow 
the sata chipset from a pc and hook it to the 50 pin scsi as its bus 
interface. We ought to be able to buy that at digi-key for under 15 
bucks a chipset. If it gets more complex than that, we've chosen the 
wrong chipset for our design. Go look at a different venders product 
line.

Heck, even the credit card stuff is beginning to have sata ports, 
maybe we could write a python translator script running on the gpio 
bus to access a 4GB file on the sata drive hooked up to it. The 
bananna pi m2 is $32, has a sata port and at least two ways to talk to 
it.  And if we ever get a usb-2 port, adapter cables ($10) that claim 
usb-3 conpatability run just fine on a raspi 3b's usb-2 port.  Just
slower.

Here is the directory of such a hookup on the raspi driving my big lathe:
pi at picnc:~ $ ls -l /media/slash
total 559412
-rwxr-xr-x  1 pi   pi      131097 Jul  6 09:17 config-4.4.4-rt9-v7+
-rw-r--r--  1 pi   pi        2901 Jul 26 05:14 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-2_armhf.changes
-rw-r--r--  1 pi   pi        1221 Jul 26 05:14 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-2.debian.tar.gz
-rw-r--r--  1 pi   pi        1217 Jul 26 05:14 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-2.dsc
-rw-r--r--  1 pi   pi        2901 Jul 26 09:26 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-3_armhf.changes
-rw-r--r--  1 pi   pi        1220 Jul 26 09:25 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-3.debian.tar.gz
-rw-r--r--  1 pi   pi        1217 Jul 26 09:25 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-3.dsc
-rw-r--r--  1 pi   pi   165089993 Jul 26 07:01 linux-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7.orig.tar.gz
drwxr-xr-x  4 pi   pi        4096 Jul 26 11:33 linuxcnc
-rw-r--r--  1 pi   pi    10971234 Jul 26 05:11 linux-headers-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-2_armhf.deb
-rw-r--r--  1 pi   pi    10971008 Jul 26 09:23 linux-headers-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-3_armhf.deb
-rw-r--r--  1 pi   pi    11054232 Jul 26 05:14 linux-image-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-2_armhf.deb
-rw-r--r--  1 pi   pi    11055266 Jul 26 09:25 linux-image-4.14.43-rt31-rc1-v7_4.14.43-rt31-rc1-v7-3_armhf.deb
-rw-r--r--  1 pi   pi      946212 Jul 26 05:11 linux-libc-dev_4.14.43-rt31-rc1-v7-2_armhf.deb
-rw-r--r--  1 pi   pi      946022 Jul 26 09:23 linux-libc-dev_4.14.43-rt31-rc1-v7-3_armhf.deb
drwxr-xr-x 26 pi   pi        4096 Jul 26 09:25 linux-rpi-4.14.y-rt
-rw-r--r--  1 pi   pi   200646568 Jun 23 06:19 linux-rpi-4.14.y-rt.zip
drwxr-xr-x 26 pi   pi        4096 Jul  6 13:35 linux-rt-devel-4.16.18-rt9
-rw-r--r--  1 pi   pi   160948307 Jul  6 11:35 linux-rt-devel-4.16.18-rt9.tar.gz
drwx------  2 root root     16384 Jun  7 18:51 lost+found

As you can see, I've been playing at building real time kernels. :)
I've sorted out how to backup the sd card that raspi 3b boots and runs 
from so a test install of that pile of .deb's made from 4.14.y-rt is 
maybe next.

Or build the 4.16.18-rt9, plenty of room left as I've only used 7% of:
that 60GB SSD so far. Itches to scratch, all of them. ;-)

> >> On Jul 29, 2018, at 1:56 PM, Gene Heskett <gheskett at shentel.net>
> >> wrote:
> >
> > But we seriously need a sata interface, and to widen the market
> > count, it should not be an adapter from scsi to sata, as that would
> > limit it to use with the relatively few scsi interfaces about. It
> > should plug directly into a multi-pack. And because the drives are
> > huge in comparison to what the coco can address, how about a dip
> > switch to set the offset such that it could mimic 50 or so 2GB
> > drives. Or even a register that could be poked from the startup to
> > set that offset for /s1, leaving /s0 available as the default boot
> > drive, but all on one SSD.
> >
> > --
> > 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>
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco



-- 
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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