Date   : Fri, 09 Nov 2001 09:59:20 +0000 (GMT)
From   : Sprow <rsprowso@...>
Subject: Re: 2 player gaming

On Thu, 8 Nov 2001, Thomas Harte wrote:

> >  I'd be concerned that there was no error checking/resyncing capability on
> >  the packet.
> >  
> >  A simple 16 bit CRC will help,but I'd also suggest some form of magic
> >  'start of header' byte and then byte stuffing within the packet.
> >  
> >  Currently,dropping a single byte will cause all sorts of problems,
> 
> Oh, I assumed that was all catered for in the underlying connection method,
> and could be considered to be a solved problem. Certainly for internet use,
> TCP is intended rather than UDP. Does that sound reasonable - part of the
> aim is to make everything simple enough for as many emulators as possible to
> grow the functionality, even if emulator:emulator communication is likely
> not to work if the emulators are not exactly as accurate as each other.

The document hinted that an aim was to keep the volume of data to a
minimum,and that even a beeb with 2400 modem could cope.

By example,consider someone using an actual BBC machine:

If the beeb is busy (for example) doing something in the game with
interrupts turned off it's quite possible that bytes from the modem could
collide in the serial interface as there's no FIFO in there.

Sure,the 6850 tells you about collisions,but the OS does nothing about it
other than pass an event round.

Maybe I misinterpretted it,but remember not everyone has a TCP/IP stack
running!
Robert.