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From: grunau_b@husc4.UUCP
Newsgroups: comp.sys.atari.st
Subject: Query re: text scrolling in windows; text mode
Message-ID: <1152@husc6.UUCP>
Date: Mon, 2-Feb-87 16:31:49 EST
Article-I.D.: husc6.1152
Posted: Mon Feb  2 16:31:49 1987
Date-Received: Tue, 3-Feb-87 07:25:03 EST
Sender: news@husc6.UUCP
Reply-To: grunau_b@husc4.UUCP (Justin J. M. Grunau)
Organization: Harvard Science Center
Lines: 55


Why is it that on the ST, the standard for scrolling text is a screen separate
from GEM, whereas on the Mac one always does one's scrolling inside windows?

I ask this, because it seems clear to me that the ability to have the menu bar
available at all times is very useful -- consider for instance being in Uniterm,
and you want to check the time.  You may of course at any time press HELP and
you will get a GEM screen with menu bar, from which you may choose a desk
accessory that will tell you the time.  But the crucial point is that you must
then RETURN to the scrolling screen, and LOSE the clock.  When you are using a
terminal emulator on the Mac, you can have the alarm clock ticking away up in
a corner at all times, clearly a highly useful feature.

I assume there is something to this that is more than mere convention.  Degas
does it this way, the VT52 emulator does it this way (choosing one desk
accessory does not normally preclude using another or even interacting with
another application -- why then does the VT52 DA work like this?  Degas uses
this double-screen method, perhaps for similar reasons (though this may have
simply been a design decision).

I have one hypothesis:  I remember vaguely reading somewhere that the ST
(paradoxically) has two modes -- text and graphics -- and that in text mode,
you get automatic scrolling features but cannot do text, whereas in text mode
you can have text but do not get automatic scrolling, etc.  I say paradoxically,
because the ST (like the Mac and Amiga) are supposed to be ALWAYS in graphics
mode -- certainly the ST video interface does NOT support true text mode in the
fashion of IBM.  Try comparing Hercules text mode to the ST -- you can go into
an editor on the IBM, hold down the PageDn key, and watch whole pages of text
flash by AS FAST AS THE KEY REPEATS.  Try this on the ST -- you will hear the
key repeating, but the screens of text will be drastically behind.  So I am
not at all clear on what the purpose of this alleged text mode is, if it
lacks hardware support and the speed that text mode usually provides (one of
the reasons people think Microsoft Windows is so slow is that it runs in
graphics mode on the IBM).  Even colour displays on the IBM, while slower than
Herc. mono, are vastly faster than the ST's text-plotting.  I am hoping the
blitter chips with make text plotting/scrolling much more pleasant.

Can anyone clear this up for me?  Is there a restriction in GEM/TOS that is
nonexistent on the Mac that forces one to do scrolling on separate screens
without the menu bar, or is it just a preference not to code GEM-specific
applications?  Are my impressions on text/graphics mode accurate, and will
the blitter chip speed up text plotting as I assume it will?

	Thanks much,

									JJMG

grunau@husc4.UUCP
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