The only time I've seen it go over 64 was when stepping through the T-Word code
and watching the buffer byte while sending a track (128 bytes + header) from
sardine.But I may have been watching the wrong byte in memory.
As far as the 64 byte limit, I had a heck of a time getting that to work
properly with the Android device. With Windows, the XON/XOFF works pretty well.
I ended up sending 8 byte chunks and then checking for a flow control byte. A
pain, but I think I have the timing right.
On Monday, October 17, 2016 2:16 PM, Mike Stein <mhs.st...@gmail.com> wrote:
Looks like John beat me to it ;-) Steve played with expanding the buffer a
long time ago while we were playing with the M100-on-the-Internet but never got
it working 100% reliably, so we ended up handling XON/XOFF in the bridge
hard/software instead which could respond instantly. m
----- Original Message ----- From: John R. Hogerhuis To: Model 100
Discussion Sent: Monday, October 17, 2016 5:05 PM Subject: Re: [M100] mComm
On Mon, Oct 17, 2016 at 1:11 PM, Kurt McCullum <kurt.mccul...@att.net> wrote:
John, Thanks for info. Is that a TELCOM limit? The reason I ask is
because when running virtual T with TS-DOS, I notice that the buffer can go to
255. Or at least the byte which holds the buffer size.
In my experience I've found that all 8-bit bytes go to 2^8 - 1 = 255
Just teasing :-) It could but it should never in practice have a value > 64.
Have you observed a higher value than 64?
It's not a limitation of TELCOM per se, it's a limitation of the receive
interrupt handler logic and the size of the circular queue-on-array reserved
for receiving bytes. The same receive handler is used for TELCOM and BASIC
access to the serial port.
See http://www.club100.org/ftp/m100-hiddenpowers-3.pdf Page 186
It shows a receive buffer of 64 bytes. If it went beyond the bounds, unmasked,
I would expect it to corrupt other data structures.
The high-water mark for the buffer is 40 (the point at which the receive
handler sends XOFF), which probably makes more sense in the context of a 64
byte buffer than a 255 byte buffer :-)