HP-48SX Remarks

Now that the HP 48SX has officially been introduced, I can join the notes fun.
However, I will not attempt to advertise the HP 48SX; we have sent advance
units to several comp.sys.handhelds participants, and they can give unbiased
reviews that are more believable than anything coming from Corvallis.
(This should also indicate HP's interest in the notes groups, and you will
observe many features in the HP 48SX that correspond to wish lists that
have been published here.)

What I will do instead is submit remarks from time to time to correct
possible misstatements or answer questions that I see in the notes.  In this
note I will hit several from notes that have appeared on the net in the last
few days, rather than try to make individual responses to those notes.

In no particular order:

* The LCD pixel color comes from the STN display with a filter that changes
the normal "Prestone" background color into a less gut-wrenching pale
rose-green.

* When you see a function count like "2100" for the HP 48SX or "1500" for the
HP 28S, these figures should be used "for comparison purposes only."  The
figures were derived from the number of separate computation paths associated
with the different argument combinations for user-commands, plus an attempt to
count the various nonprogrammable operations.  This gives a reasonable weight
to commands like +, which on the HP 48 has 25 separate dispatchees, each of
which would be a separate command on other calculators.  Making a meaningful
count is very difficult; for example, many calculators have several built-in
unit conversion factors that automate converting a magnitude from one specific
unit to another.  Each of these would be counted as a "function."  How does
one compare this with the CONVERT command on the HP 28, which effectively has
an infinite number of such conversions (and still falls short of the
integrated unit management system on the HP 48)?  Dan Allen's count of 247
functions for the HP 28 and 353 for the HP 48SX presumably is a count of the
separate command names, but wildly undercounts the HP 28 and HP 48 compared to
the other calculators.

* The HP 48SX has 32K of RAM built-in (expandable to 288K).  Approximately 1K
of this is used by the operating system.  Also, unlike on the HP 28, the HP
48SX display uses main RAM for its memory, which allows a variable logical
size for the display and separate "pages" for the graphics and stack displays.
This costs another 1K of RAM, leaving ~30K available to the user in a "clean"
machine (another 1K disappears if you activate the graphics display).  We
could have built in more RAM (raising the price even more), but we felt that
the total combination of ROM & RAM was best left to the customer by using
plugins, given the 512K limitation.

* There are 6 soft keys, aka menu keys.

* The display is described as "8 lines x 22 characters."  Specifically, it is
64x131 pixels, which translates to 8 x 22 in terms of conventional 8x6 pixel
characters.  The calculator actually uses 3 fonts: 10x6, 8x6, and
6x<variable>, so that the number of lines varies according to the context.

* The alarm system supports "control alarms" as well as "appointment alarms,"
where the former is the autoexecution of a program or other object at the
alarm time.

* Individual pixels can be turned on, off, or tested.  There is quite an
extensive set of graphics operations.

* Two 32K or 128K RAM cards can be plugged in.  Either or both can be
separately configured as part of main RAM, or as independent RAM that can
be removed with its contents.  The two do not have to be configured the same.

* HP is not "going away from RPN."  The HP 48SX is manifestly an RPN
calculator, where the RPN stack has been generalized to manage, among other
things, expression objects entered with algebraic syntax.  This means that
you can accomplish quite a lot without ever executing a postfix operation,
but the power and flexibility of the RPN stack is there when you want it.

* The hinged HP 28 case has been a mixed success--some love it, some hate it.
Thus there was no compelling reason to design a new clamshell for the HP 48,
other than the problem of how to cram a lot of functions onto fewer keys
than the HP 28.  The HP 48 comes with a padded brushed nylon case; that, plus 
the quick reference guide in its designated slot provides sufficient
protection for the keyboard and display.

* The HP 48 has the Kermit file transfer protocol built in, so you don't need
any additional software or hardware for calc-to-calc communication.  To
communicate with a PC, you need a cable ($35) with the HP 48 4-pin connector on
one end and an IBM or Mac RS232 connector on the other, plus Kermit running
on your PC.  Kermit is public domain (with a few restrictions), and is
widely available free for any PC.  HP will sell you an interface kit ($60)
that includes a cable plus a disk that contains Kermit along with a number of
utilities for the HP 48 (including one to capture I/R output from the HP
28). 

* The range of calc-to-calc 2-way I/R is a few inches.  This is deliberate:
(a) To minimize power consumption by the receiver, which must be running
full bore all the time; (b) education testing organizations have requested
the limitation--given (a), it seemed appropriate to cooperate.

Bill Wickes