Re: A little more information

[Chris Albertson <chrisalbertson90278@yahoo.com>]

Tom Droege wrote:
> 
> Arne and all,
> 
> Let me respond point by point.
> 
> 1)  I am sick of working on 1).  But I will have a another go at it in a
> day or two.  This requires writing some test software so that I can put the
> board in a loop and put a scope on it.  There is always the chance that I
> will find a simple problem.  But I am not optimistic.  I have struggled
> with the problem too long.  The memory board is bigger and more complicated
> than it needs to be.  Always a recipe for disaster.
> 
> 2)  Unless someone knows of a byte parallel PCI card with 16MBytes of
> memory this is a big project.  Bigger than other solutions I have in hand.
> 
> 3)  As I understand it, the ECP contains a FIFO.  Possibly someone on the
> list had interfaced to the ECP and understands it.  If so please speak
> up.  At the moment this looks like the simplest solution, but it does need
> software.  As Chris points out there is standard software for this.  Note
> that there are high speed scanners that work into the parallel port, so it
> must be possible to go at our rates.
> 
> 4), 5)  We have this type of solution available.  Bill Haynes has designed
> a serial card that will go at 2.5 GHz.  This over a short Base 10
> cable.  There are cheaper drivers that will go slower and should be able to
> run over longer distances.  This requires that we build a board that plugs
> into the present DB-25 connector and has a small board where we put some
> sort of control chip which then drives the serial cable.  Bill has done
> similar things before so it should not be much of a problem.  We are all
> lined up to start this project.  Then Chris suggested that the parallel
> port might work.  The PCI card that goes into the computer exists and has a
> FIFO in it.  No problem going at our 3.2 MBits since it is working at 2.5
> GBits.  ThePC end card is already designed with a dual driver.  It can
> either drive a Base 10 cable, or you can solder in a Laser driver and go
> over fiber optic.  Then there is no practical distance limit.  I consider
> this the delux solution.  But I am pretty confident that it will work.
> 
> I very much agree about retrofitting all Mark IVs to run with the same
> hardware system.
> 
> My vote is to have a college try at 3) and if that cannot be made to work
> easily to go to the PCI serial solution.
> 
> Any one with a Mark IV or a Mark IV test set up want to have a go at
> 2?   Note that if someone other than Chris (or one of the Mark IV owners)
> wants to have a go at 2) we could arrange for Chris to send the test set up.
> 
> If anyone is up for it, I will build a kludge that plugs into the Mark IV
> driver end and puts the signals on the right pins to drive the parallel
> port.  I consider this mostly a software project.  One says preps the
> parallel port to accept data, says "start scan" to the Mark IV, and then
> looks to see what his software did with the 16 MBytes that the Mark IV sent.
> 
> The other way to do this is for me to build the kludge here, set up a
> computer, and have someone send test software that will prove that it
> works.  This is less desirable for me since it interrupts the Mark IV
> production.  There are more of you that would like to have a Mark IV.
> 
> What do the rest of you think?

Your current parallel cable is so close to what a standard PC wants to
see that I think we should make a simple addator and plug it in.
Likely all that is needed is an inverter or two.

Next, if you want a fiber link back to your office, den or attic, a standard
PC makes a real nice parallel to Ethernet converter.  




-- 

--
   Chris Albertson             
   chrisalbertson90278@yahoo.com
   Redondo Beach, California
   home: 310-376-1029
   cell: 310-990-7550