Gerald Emig wrote:
> > And as Lawson says. "Spacing condition" is called BREAK, sending BREAK or breaking
> > condition. A permanent LOW level (-12V) on the RS232 side.
> >
>
> As far as I know -12V is logical HIGH on the data lines of
> RS232.
We (at least in Scandinavia and the Process Control industry) speak of HIGH/LOW to
indicate the voltage levels, and Logical 1 and Logical 0. For me there is no "logical
HIGH". Low is -12V which is a logical 1, and vice versa. Perhaps other communities has
other naming conventions, but I have not seen any over the last 16 years.
> Unfortunately most people are not willing or able to work in
> their computer with a soldering iron. And additionally the
> "modern" main boards with their integrated chipsets leave you no
> chance at all.
I know!!! We were OTOH designing all the hardware, and the first 6 years in that
company, the hardware guys was completely ignorant to the software needs. We ended up
with a RTOS that spent 75-80% of the CPU time for hardware overhead and multitasking
context switching. In 1989, I objected strongly to this, and got a policy change in
place. The RTOS guys (mainly me and one other guy) became responsible for hardware
"design" and the hardware people became the "implementors" (if using programming naming
conventions.) The following model had twice as much hardware resources (A/D,
D/A channels, Digital I/O and serial ports) and yet the CPU load went down to 10-15%
for hardware overhead and multitasking.
Interesting to see that similar arrangements was made in TransMeta, and I believe that
most successful hardware ventures in the future, must start from a software requirement
point of view, not the ease of implementation for the HW designers.
> The developers of the IBM-PC choosed the latter, I assume the
> additional AND-Gate (74LS08) was to expensive and they could not
> imagine about data rates higher than 2400 bps (although they
> implemented an interface up to 9600 bps).
> BASIC was fast enough to talk to 300 bps acousticcouplers in
> these days, you see?
Well, not entirely true. My first Quality Assurance & Test program, was written in
Basic and ran on a Osborne 1.
9600 bps, and I implemented a co-operative multitasking scheduler in Basic, to do
communications, printing, data input, and analysis in parallel. I did not manage
storage to floppy disks. It was possible to do a great deal of things in those days.
> I agree, but this change of hardware will probably never happen.
I believe it will, at chip level though, default turned off, and can be activated.
Niclas
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