[COFF] 52-pin D-Sub?

[Arthur Krewat]

On 2/28/2020 9:11 AM, Clem Cole wrote:
>
> [1] The original PC/AT used the NS8250 UART with no input buffering, 
> which went through a couple of generations, eventually begat the *550 
> version and had I think an 8 character input buffer.  But IIRC none of 
> them had hardware flow control.   I forget the # now, Moto made a nice 
> dual UART with 16 chars of input buffering, that many of us on Unix 
> workstation business used, but when we moved to BSD 386 and Linux, we 
> were stuck with PC hardware, which had a particularly hard time with 
> things like the Trailblazer  (which was the modem of choice for UUCP).
>
I ran a BBS for a few years back in the early 90's, and used a 486DX2-66 
as my "front-end" to a Sun SPARC-IPC USENET setup. Using two V.34 and 
one Worldblazer, running them at 38,400 baud, and taking advantage of 
compression, it ran 100% download, 100% upload, or a combination across 
three modems without even showing much load at all. It could have easily 
taken more if I had the physical space (and the IRQs) on the ISA bus to 
add more serial ports. Of course, the interrupt coalescing of the 
16550's helped a lot. And I don't know what the saturation point was...

That was on x86 SVR4.2 (Consensys), using a shareware 16550 driver of 
the time. The Worldblazer talked to a Trailblazer at Motorola for my 
USENET feed and used G protocol, acceleration built into the Telebits.

8250's and 16540's were horrible. Much like DZ11's, eh? ;)

art k.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://minnie.tuhs.org/pipermail/coff/attachments/20200228/19079e57/attachment.html>