🚀 go-pugleaf

In article <1993Jan11.204008.28876@njitgw.njit.edu> dic5340@hertz.njit.edu (David Charlap) writes:
>>I am experiencing problems running a DOS communication TSR in
>>a VDM dos 5.0. Indeed, I cannot use a baud rate faster than 9600.
>>Can anybody give some advice in order to rise it up to 57Kbd or
>>eventually even 115200 ?
>Not without changing a piece of OS/2.  OS/2 will not (or can not)
>provide a DOS box more than 1000 interrupts per second.  9600 baud
>requires (at no parity, 8 data bits, one stop bit, one start bit) 960
>interrupts per second to receive a continuous stream.  Faster speeds
>will go beyond the limit and fail.
>Note, you can set the port to faster, and you can certainly send data
>at those speeds, but receiving at high speeds will require interrupts
>to go faster than OS/2 allows.  Either use real DOS or an OS/2 comm
>program.

It should also be pointed out that some people have reported increased
DOS session communications performance with the SIO communications
drivers, available via anonymous ftp from ftp-os2.nmsu.edu (in
/pub/uploads at the moment; look for a file that begins with "sio").

Also, this limit is not a hard and fast one.  It is system dependent.
It also may be impacted by whether or not you have a buffered UART.

I do agree with the main conclusion, that switching over to an OS/2
communications program is your best bet.  They were designed from the
start to multitask.

-- 
Timothy F. Sipples      | Read the OS/2 FAQ List 2.0i, available from
sip1@ellis.uchicago.edu | 128.123.35.151, anonymous ftp, in /pub/os2/all/info
Dept. of Econ., Univ.   | /faq, or from LISTSERV@BLEKUL11.BITNET (send "HELP")
of Chicago, 60637       | [Read the List, THEN post to ONE OS/2 newsgroup.]