why the program cannot run when i set large I/O buffer size?

[yyh]

I need to read about 800000 bytes(a bmp file) from serial port into PC. And i set I/O buffer 800000 bytes. then the program cannot run and shows error.
is there anyboby who can help me?
thanks a lot.

[Parks]

The maximum buffer size for a 16550 UART is 16 bytes.
Try reading the buffer in <16 byte chunks and concatenating them.


"yyh" wrote in message news:50650000000800000020480000-1019262487000@exchange.ni.com...
> I need to read about 800000 bytes(a bmp file) from serial port into
> PC. And i set I/O buffer 800000 bytes. then the program cannot run and
> shows error.
> is there anyboby who can help me?
> thanks a lot.

[yyh]

the problem is :
when i set buffer size 4000 bytes, the programm can run. the bytes i need can be read into PC from serial port. but when i set it 800000 bytes, the program cannot run. the most strange thing is, when i first set buffer size 4000 and let the program run, then i set buffer size 800000 bytes again, it works. i cannot understand .
really need help from everybody.
thanks in advance!
the attached file is my program.
another problem is about "VISA write serial port", i want to open a bmp file and write the data(no header) into serial port. after than another device will receive the data in serial port. how can i realize it?
thanks!