6 Sep
2018
6 Sep
'18
12:28 p.m.
On Sep 6, 2018, at 3:14 PM, Carlo Pisani via cctalk
<cctalk at classiccmp.org> wrote:
why do you say that?
a vt100 terminal requires only a text VDU (video display unit) with
hw-scrolling support, and a piece of software to support the VT100
protocol (escape-codes decoded into action for the VDU).
in fact, my Digital VT200 comes with an ASIC chip for the VDU, while
the software side runs on an Intel 8051 MPU that directly interfaces
the keyboard, the VDU, and the serial line
this doesn't look complex
The work of a VT100 is quite a lot more complex than that of a VT52 (many more screen
operations, and more complex control sequence parsing). With the hardware technology
available at the time, it was a pretty tough job. Does the VT100 have a microprocessor?
It may predate those. In hardwired 7400 series logic, it isn't an easy job.
The VT1xx series successors did a number of things: eliminate expansion to simplify
things, offer both basic (VT101) and extended (VT102) options in separate designs
optimized for the task, and use newer designs to take advantage of the rapid evolution of
available silicon. The VT2xx series did the same thing yet again. So the successors of
the VT100 are less complex (smaller boards with less stuff), less expensive, and/or more
capable (VT220 for example).
Similarly, going in the opposite direction, a VT05 does far less than a VT100 with much
more hardware, because the individual components were less capable.
paul
cause
it's the simplest, I guess
The VT100 was quite complicated compared to
contemporary terminals at the
time of its introduction.