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From: K538915@CZHRZU1A.BITNET.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: Terminal emulation .....
Message-ID: <8706050529.AA06867@ucbvax.Berkeley.EDU>
Date: Thu, 4-Jun-87 08:12:14 EDT
Article-I.D.: ucbvax.8706050529.AA06867
Posted: Thu Jun  4 08:12:14 1987
Date-Received: Sat, 6-Jun-87 11:46:10 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
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John T. Grieggs writes:
>............................ Incidentally, VT-52 emulation is built into
>the OS ROM, which makes it relatively easy to add VT-100...

If life was that simple! UniTerm uses 3 functions of the VT52 emulator
(or rather the corresponding VDI-Escape):

                  - character output without attributes (+invers)
                  - absolute cursor postion (gotoxy)
                  - bell

Not even the VT52 emulation in UniTerm uses the built-in VT52! There are
a number of reasons for this, but just consider double width/height
characters: after you receive the escape sequence to turn a line into
DW/DH characters you have to convert the line with ALL ATTRIBUTES to
DW/DH this means you have to have a copy of the current screen contents
in character form somewhere, this naturally implies that you have to
decode the escape sequences yourself! There are at least another 2 pages
worth of reasons why you can't use the TOS-VT52 emulation, but I think
this example was enough!


                        Simon Poole
                        K538915@CZHRZU1A.BITNET