From: "Geo" 

"John Beckett"  wrote
in message news:4180c887.2659273{at}216.144.1.254...
> "Geo"  wrote in message
news::
> > Poking the number into screen memory instead of using a display function
is
> > much faster.
>
> I never never found out exactly how the Windows NT family handles this,
> but it is a lot less useful than was the case when we played with DOS.

Well it's only an uneducated guess but I would think that's exactly what
directX is all about, no?

> A 16-bit program would often access the COM1 serial port by performing i/o
> with the 3F8h ports. Such programs often run successfully under NT, but
> the i/o instructions cause a hardware interrupt and are emulated by the
> operating system. So, a single 'in' instruction to read a byte from COM1
> might end up executing 1000 instructions in the OS.

Probably a lot more than that, I have an old DOS program called crumbl.com
that takes the characters on the screen and makes them fall to the bottom
of the screen (in dos fullscreen mode). It runs really really slow on NT.

> At any rate, worrying about these low-level details is not a good way to
> learn any high-level language.

It's a good way to learn the limitations of a high level language .

Geo.

--- BBBS/NT v4.01 Flag-5