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From: conte@crest.crhc.uiuc.edu (Tom Conte)
Newsgroups: comp.sys.handhelds
Subject: First look: TI-81
Keywords: TI-81
Message-ID: <1990Sep5.195144.26901@ux1.cso.uiuc.edu>
Date: 5 Sep 90 19:51:44 GMT
Sender: news@ux1.cso.uiuc.edu (News)
Reply-To: conte@uiuc.edu (Tom Conte)
Organization: University of Illinois at Urbana
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Today I took a look at one of the first TI-81's that our bookstore
received.  Here are some (rather sketchy) first impressions:

The calculator is about as long and wide as the 48SX, but not quite
as thick.  It had a snap-on cover that swings around and locks onto
the back.  The keys have three functions: primary (on the key face),
2nd (above) and alpha (to the lower left).  There are no soft keys,
but there are cursor keys.  There are also menu keys.  Let me explain.
Instead of having a menu appear in the last line, the menu's appear
in vertical lists:

	1: Prgm1
	2: Prgm2
	3: Prgm3

And there are functions (written in all-caps) that appear above the
menus.  One selects a function using (48SX-style) cursor keys, it
hightlights, then one hits ENTER.  The cursor suggests the mode.
Alpha mode has a blinking `A' as the cursor, for example.

The display is an LCD of better-than-28S quality contrast (IMHO).
The keys are the (in)famous `squishy' type.  I believe the display
had eight lines to it.

It uses algebraic logic (of course) and has a last value stack (or
paperless printer) much like the 27S.

Graphing is done in several steps: you hit `Y=' which displays a
menu of formulas to graph.  You enter the formulas using `X|T' as
the independent variable.  the RANGE key brings up a menu to select
an appropriate range (no auto-ranging, aparently), and GRAPH performs
the graphing process.  You can digitize points using the arrow keys.

There seems to be symbolic math support, with differentiation (symbolic
integration? I don't know).  The inside cover claims the overall design
was inspired by a text on calculus published by Addison-Weseley.

The memory seems flat (no directories), but values and equations
can be named.  Programs occupy a different `space' from variables.
Programming is imperitive in nature, much more an outgrowth of the
earlier `keystroke programming' style than RPL is.  Control flow
is via a GoTo to a line number, with a compliment of traditional
conditional tests.

I don't know how much memory the machine has.  I don't know if it
is expandable, but the manual mentioned nothing of the sort.  The
case seemed to not have any places for modules, but again, I'm not
sure.

Overall, the machine was easier to use than a 28S (dag nammit). Of
course TI is famous for taking ideas from HP, improving on them a
touch, and packaging them at a lower price.  This feels like an
improved 28S, targeted to catch that market, not something that
compares to the 48SX.  No equation writer on the 81.  No polar
plots.  No directories, no libraries, etc.

However, It is the first TI in a very long time I actually contemplated
buying.  I'm an HP calculator collector (the few, the proud). Liking
a TI for me means they've come a long way.

------
Tom Conte	  Center for Reliable and High-Performance Computing
 conte@uiuc.edu   University of Illinois, Urbana-Champaign, Illinois
  Bachelor tip #48: used gym socks make great no-pest strips!