Path: utzoo!utgpu!water!watmath!clyde!att-cb!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!cory.Berkeley.EDU!bowdidge
From: bowdidge@cory.Berkeley.EDU (Robert Bowdidge)
Newsgroups: comp.sys.tandy
Subject: Graphical interface for Model 3/4
Message-ID: <1927@pasteur.Berkeley.Edu>
Date: 29 Mar 88 16:58:11 GMT
Sender: news@pasteur.Berkeley.Edu
Reply-To: bowdidge@cory.Berkeley.EDU (Robert Bowdidge)
Organization: University of California, Berkeley
Lines: 27

Robert Freimer (freimer@svax.cs.cornell.edu) gave the best reason why the
project (put a mac-like interface on the TRS-80 Model 4) couldn't work --
speed of the hi-res board.  The puppy takes quite a while (2 seconds?) to
clear the screen. Does anyone know why the board is so slow? Is it just the
OUT instructions take a certain amount of time, or can the graphics board
delay the processor 'till it finishes an instruction?

George Madison's suggestion about needing a good input device is correct; the
solution might be to just get an Apple mouse.  The mouse used for both the
Apple II line and for the Macintosh is not a proportional one like the
Radio Shack mouse but (what I believe) is a superior design, sending a signal
when it's gone up, down, left, or right a unit.  We could poll it during
interrupt time (as is done on the Apple IIc.)  

Finally, George's comment about Z-80 versus 6502: I thought that a 6502 ran
faster because it was able to pipeline instructions.  Almost (99+%) every
cycle is a memory fetch, and since both can only deal with 8 bit data, I would
assume that this could make the 6502 faster.  It's also the first "RISC"
machine; it's got a simple instruction set that can be operated fast.
Expert opinions welcome.

Anyone want to start coding?

-- Robert
                                                           Robert Bowdidge
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