[comp.sys.amiga.tech] serial multiplexers

jbwaters@bsu-cs.bsu.edu (J. Brian Waters) (06/02/89)

In article <18984@cup.portal.com>, FelineGrace@cup.portal.com (Dana B Bourgeois) writes:
> I have this glimpse of the Amy hardware running flatout with a multi-
> plexer of some sort running off it splitting up the bit stream say
> eight ways to eight UARTs(?).  Maybe Ser: would have a problem with it.
> But couldn't a custom device driver handle it?  OK, OK.  Go ahead and
> let me have it.  *WHY* won't it work?

It should work just fine.  I have had this idea before,  but I never got around
to finding a source of information on serial multiplexers.  A replacment
serial.device should do the trick,  and you would want the mulitplexer to not
have any inband controls so 8 bit protocols would still work.

Does anyone know where I can find out about multiplexers prices and protocols?

This might make a good summer project,  if a multiplexer would be cheaper then
a multi-serial card.

-- 
Brian Waters              <backbone>!{iuvax|pur-ee}!bsu-cs!jbwaters

rokicki@polya.Stanford.EDU (Tomas G. Rokicki) (06/02/89)

> > I have this glimpse of the Amy hardware running flatout with a multi-
> > plexer of some sort running off it splitting up the bit stream say

> It should work just fine.  I have had this idea before,

This may work, indeed, but getting the software to fly would be a major
pain.  Also, don't forget that a serial line usually is bidirectional,
and there is no way Amy's serial port will read at 1,000,000 baud.

I will personally guaranetee you that, especially with the DSP available,
the time investment would not be worth it.  Indeed, there are a lot
of very very excellent neat software projects, each of which isn't
terribly difficult, that have been on my todo list for a long, long time.
I've been just getting busier and busier, so I'll probably not get around
to them.  They would make much nicer summer products and have a much greater
chance of being generally used.  Among these are:

	- Make GCC fly on the Amiga.  Already several people are
		doing this; ever considered contributing to the effort?
	- Making GhostScript fly on the Amiga.  It already works, but
		if we add a nice screen driver, Preferences driver, and
		IFF output, we could have a hell of a combination.
		(Stephen Vermeulen has done much of this, but a lot
		remains to be done.)
	- Add Preferences and IFF support to PLPlot---no more having
		to write a new device for each printer; just go through
		Preferences!  Also, make it accept commands, equations, and
		data in a script file, rather than requiring C compilation.
		(I'm almost done with this latter.)
	- Add an ARexx port to mg3---Mike Meyer is doing this, and
		will do a much better job than I could have.  Or any
		popular utility.
	- Test, debug, and further develop DNET/RFS---this could be the
		hit of the year.  Perhaps modify the link protocol so
		it will work over lines that aren't eight-bit transparent.
	- Attempt to hack VM support onto the Amiga.  Perhaps not so easy,
		but we could all learn a lot from a few such attempts.
	- Write a simple, clean, structured drawing package.
	- Write a SCSI tape driver for backups.

There are a lot of really neat things to be done.  Most of the above
(except VM and draw) would be (IMHO) easier than figuring out how to
replace serial.device with a multiplexer, and would have far greater
impact on the community as a whole.

There is so much energy out there, and so much of it is being directed
into duplicate efforts and dead ends.  I wish there was some sort of a
clearinghouse for such ideas where expertise could be exchanged and
efforts unified somehow . . .

-tom

wolff@cs.purdue.EDU (Robert M. Wolff) (06/02/89)

From article <9650@polya.Stanford.EDU>, by rokicki@polya.Stanford.EDU (Tomas G. Rokicki):
> [....discussion of projects for Amy....]
> 	- Test, debug, and further develop DNET/RFS---this could be the
> 		hit of the year.  Perhaps modify the link protocol so
> 		it will work over lines that aren't eight-bit transparent.
> [....]
> There are a lot of really neat things to be done.  Most of the above
> (except VM and draw) would be (IMHO) easier than figuring out how to
> replace serial.device with a multiplexer, and would have far greater
> impact on the community as a whole.
> 
> -tom

Well, Tom, I personally would REALLY like to see dnet using flow control and
7-bit (flow control is more important to me personally here at Purdue with
their really odd fibre optic network...) 

Anyway, between Matt's dnet, dnet-nfs (up-and-coming) and Software
Distillery's NET:, we REALLY have some potential...I would like to see
Matt's DNET working on the parallel port so I could have my serial link
up at 9600 to campus and NET: between my amiga and another amiga so I
can use the printer on the other amiga and his resources too... :-D

I'd like to contribute some time and effort...I've got a 'bit' of time
this summer in the evenings...

bob

-- 
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/*************  MS-Dos? Me? No, You must be mistaken! *************/

FelineGrace@cup.portal.com (Dana B Bourgeois) (06/07/89)

I retract the suggestion of multiplexing SER:, and I offer my help on
one of the programming projects Tom mentioned.  It'll be just a wee 
bit 'o help since I'm a 3 month veteran of C but I have some time and 
plenty of enthusiasm.  Who needs another pair of hands?

PS.  Email me please.

Dana