Date   : Tue, 16 Nov 2010 05:25:15 +0100
From   : rick@... (Rick Murray)
Subject: Beeb Networking - Was: No wonder CompSci graduates

       <4CE19169.6090309@...>
Message-ID: <4CE207AB.4030802@...>

On 15/11/2010 21:00, Jules Richardson wrote:

> mainly that it isn't always the most reliable,

It's a shame they picked such crappy sockets. And the plugs, as I've 
discovered on my eeePC while fumbling around in the dark (to pull 
another movie off the NAS), are a pretty good fit into any RJ45 ethernet 
socket. Meh.


> and that it replaces many much simpler ports (e.g. serial and parallel)
> that were able to do their jobs without a big mess of hardware and software.

Much simpler *slower* ports that *do* actually need highly specific, and 
frequently conflicting, drivers.


I'll tell you what - I'll show you a TV capture card (how I watch TV 
these days) and two 8Gb USB sticks that can copy a Gb file between them 
in two minutes.

And I'll go a step further and show you a Psion 3a which is useless 
without the specific Psion software, assuming something else doesn't 
think it owns the serial port. And then I'll go a step further and show 
you a 115kbps link between two computers pushing files across using 
Zmodem; now largely abandoned as the old 10baseT did it better; not to 
mention 100baseT.

I can show you numerous USB ADSL modems, and a multitude of Ethernet 
ones. I can show you *zero* serial port implementations.

I can show you all sorts of magical printer/scanner devices using USB. 
Switch to the parallel port in whoo-hoo-ECP/EPP/megamega mode and you 
take an instant (and severe) speed hit.

Oh, and I can plug any of my USB devices into any port and it'll still 
work. Sometimes with Windows doing silly things like reallocating what 
drive letter the device is seen as, but it still works. And other 
hardware (tablet, TV card, etc) just works.

I'm not aware of any serial software that you didn't have to tell it 
which serial port (and in the case of certain RISC OS products, had to 
hack the hell out of it if you had an sp_dual and it only knew of the 
internal port...). Likewise, in the old days it was common for LPT1 on 
the motherboard and another LPT (LPT2, LPT4?) on an I/O card. Well, you 
try plugging a printer into the additional LPT and see how much stuff 
fails. Thankfully life was marginally better once Windows took over this 
task. Assuming, of course, Windows even recognised the port!


Assuming you have the right "sort" of parallel port (SPP, ECP, EPP; 
single vs bi-di?). Assuming you have the right "sort" of serial port 
(max bitrate? max *reliable* bitrate? rts/cts or xon/xoff?).


I *like* parallel and serial. It is all so damn simple, talking to a USB 
device is damn-near impossible without special drivers and HDKs and 
such. But in defence of USB, it pretty much just works, and it works 
quickly enough that recording live video at 2000kbit with 128kbit audio 
to a flash based device is not a problem for an embedded ARM; likewise a 
generic inexpensive netbook can play it back without issues.


USB is not perfect, but it is one of the better creations for plugging 
stuff into a computer. And my 1.6GHz machine hooked to an AverTV USB2.0 
can display a smooth picture and take accurate screenshots. Something I 
never could get from a 450MHz machine and a PCI Pinacle Typhoon capture 
card (designed for use on a Pentium233, apparently!) even using DMA, bus 
mastering, magic incantations, and a 32bit data path...


> real beebs could still be on an Econet LAN; the widget simply gives a PC (or
> anything with a USB connection) an Econet port.

Mmmm, that sounds interesting.


Best wishes,

Rick.

-- 
Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...