An HP28S wakes up



#12

Hello fellow calc fans.
I recently acquired a nice HP28S and this made some fond memories resurface. It is a very curious experience to face all the quirks in this machine, which lacks many twists of its later siblings. The hardware is truly excellent, apart from the dreaded battery door (undamaged in my copy). Even knowing that putting batteries in would be a challenge, it was still a pain. On my original 28S, the battery door actually broke spontaneously.



I had a funny experience trying to get 'N' batteries ; I went to a store dedicated to selling rare kinds of batteries (the store is actually named "a thousand and one batteries" !). When I asked for 'N' batteries, the guy immediately replied "So you have an HP calculator ?" !! Seems all the world production of this kind goes into elder HP models. Great fun.



While typing some programs, I ran into some problems :
- No such thing as a 'continue', once it is HALTed you can't restart the program

- No access to local vars in called programs : if program A has a local variable and calls program B, then B doesn't see the variable. You need to pass it on the stack - hmm.

- STO+ can't do all what + STO can : no STO+ into local variables, and for example {1,2} 'A' STO {3} 'A' STO+ brings an error

- The program editor is horrible, starts in overwrite mode, discards your nice indentation, doesn't go to the next line if you [->] at the last character of the line, etc. Cursor keys being the same as menu keys is also bad.



Other funny behavior includes :
- UNITS catalog doesn't have base units such as kg

- 'A+B' 'A' STO A doesn't crash. Then A EVAL gives 'A+B+B'. EVAL again gives 'A+B+B+B' !?

- 'SQRT 5' 2 + SQ EXPAN COLCT gives back a numerical result 17,94... instead of '4*SQRT 5 + 9'(where SQRT is the square root character)



I still like the FORMS editor, it was powerful and a lot faster than the Equation Editor on 48s. 32 kb is nice to use.
So I only wish this model would have benefited from all the ideas that surfaced in the following years. However, this one was the real innovation, the 48/49 being IMHO much less of a change in paradigm.



I think this machine deserves some space in the museum.


#13

Hi GE.

Now I remember! Around 1983 (84?, 85?)
I saw an HP calc in an electronics store,
(while shopping for opamps, dvm chips and some OTA chips).

It really blew me out because the thing would do symbolic
(named variables) work, like speed=distance / time.

I really liked that and I was a bit jealous at the time since I own an old HP41CV [as everyone here knows by now... sorry guys!]

I guess that was the 28S...?

DW


#14

Aside from my 28S I have several flashlights that use N cells.


#15

I think the community does not do justice to the 28S, which improved over almost all the faults of the admittently premature 28C. But the 28C was such a revolutionary break from the past that even HP couldn't get it perfect the first time.
I bought the 28C right after it appeared (in fact even before-I had a friend at HP at the time who gave me his rebate), and was stunned from the very first day. I used to have little programs doing complex number calculations, determinants and matrix inversions - usually either complex numbers OR matrices, since both wouldn't fit into the memory of the FX602 (yes, that's a CASIO) I used at the time - and the 28C did all this and more right from the start, without programming. I found this ability to handle compound data types more impressive than the algebraic operations in fact - the 28C did the simple derivations I could do by hand, and failed at the same ones than me, let alone do symbolic integrations.
After a year of heavy use, I hit the memory limit of the 28C, but HP issued the 28S right in time. It is still one of my favourite machines, and I never managed to become equally acquainted to the 48. Long live the 28C/S!

Andreas

#16

Hi all. All, that is, EXCEPT UNSPELLABLE.... ;-P

My 41CV uses N cells... Watch it, buddy!

Ah, yes. The machine I saw was brand new, so it nust have been the 28C. I think this was 1985?

DW

P.S. What have you got against flashlights, anyway?

Edited: 15 Sept 2005, 5:06 p.m.


#17

>1985?

No, must have been later. Bought mine in 87, and I'm sure I was one of the first customers. I pre-ordered mine before they came out. I recall the 28S came out about a year later or so.

Andreas


#18

The museum page for the 28C/S has this:

Quote:
Production Runs: HP-28C: 1987-1988, HP-28S: 1988-1992

So your recollection is right on.

#19

Whu'd I do? Whu'd I do?

#20

Well, the 28C was introduced in 1987, and the 28S in 1988, so either you're a bit off on your dates, or you're thinking of some other calculator.

#21

First off, I recommend that you have a look at the 28 series
reference materials, particularly Bill Wickes's "HP-28 Insights",
available on the Museum DVD if you don't have a printed copy.
http://www.hpcalc.org/ also has a lot of information on this
model, and of course the newsgroup comp.sys.hp48 is a good source
of information.

I agree that the battery cover is a poor design; I haven't had one
break, but that may be a matter of luck as much as a matter of
being careful. I have mixed feelings about the hinged design too.

As for N cells, they are used elsewhere, but they're unusual
enough that "new" N cells may have been in storage for a very long
time. To avoid a "Memory Lost" condition, I recommend that you
test the cells before inserting them into your calculator,
especially if they don't have a date code.

Quote:
While typing some programs, I ran into some problems : - No such
thing as a 'continue', once it is HALTed you can't restart the
program

Sure there is; use CONT, the "shifted" 1 key. Or just type in
CONT and press ENTER; it's a built-in command.

Quote:
- No access to local vars in called programs : if program A has a
local variable and calls program B, then B doesn't see the
variable. You need to pass it on the stack - hmm.

The compiler compiles a name as a local name only if that local
variable currently exists, or is defined as such in the source
code. A work-around: Suppose that your program 'A' defines the
local variable 'a', and you want the called program 'B' to use
'a'. Run a program like

<< "dummy string" -> a << HALT >> >>

Now enter (or edit or visit) your program 'B' which uses 'a'; this
way 'a' will be compiled as a local name. Finally, do a CONT to
finish the suspended program. This technique is easy enough, but
it's very easy to forget to use it if you decide to edit program
'B' at some later date. This technique works with the 48 and 49
series too. Starting with the 48G series, any name that begins
with a <- (left arrow) character is compiled as a local name, even
if it doesn't currently exist.

Of course you can pass the contents of the variable on the stack
instead.

Quote:
- STO+ can't do all what + STO can : no STO+ into local variables,
and for example {1,2} 'A' STO {3} 'A' STO+ brings an error

True enough, STO+ requires real or complex numbers or arrays, and
a global name, while + can take quite a variety of arguments, and
STO works with either a local or global name, but so what? The
"storage arithmetic" commands are intended to be rather special
purpose; STO+ is not intended to be a "short form" of + STO.

Quote:
- The program editor is horrible, starts in overwrite mode,

I prefer that editing start in insert mode, but note that
overwrite mode seems to be the default for quite a few editors.

Quote:
discards your nice indentation,

The source code that you type into the command line editor isn't
saved; it's compiled, and the resulting object is stored, thus all
separator characters (such as SPACE and NEWLINE) and delimiters
are discarded. To display an object on the stack, for editing, or
printing the object, it's decompiled, using separator characters
(and delimiters) as the designers thought appropriate.

If you want to save your source code, then write the program
within a character string. When you want to compile it, you can
use the STR-> command, or edit out the " delimiting characters
around the body of the string.

Quote:
doesn't go to the next line if you [->] at the last character of
the line,

??? So use NEWLINE (shifted SPACE key) when you want to go to the
next line.

Quote:
etc. Cursor keys being the same as menu keys is also bad.

Okay, and the cursor keys being the same as ALPHA keys on the 48
series is a bit of a nuisance too. Design decisions had to be
made; no doubt you or I would have decided differently on some
things, but I think that the designers made reasonable decisions
on the 28S.

Quote:
Other funny behavior includes : - UNITS catalog doesn't have base
units such as kg

I think that this calculator treats g (gram) as the "base unit"
for mass. While that doesn't agree with SI, it's easy enough to
insert a "k".

Quote:
- 'A+B' 'A' STO A doesn't crash. Then A EVAL gives 'A+B+B'. EVAL
again gives 'A+B+B+B' !?

Well, I'd certainly hope that it wouldn't "crash", but a "Circular
Reference" error (as on later models) would be nice. But even the
latest models don't catch all non-obvious circular references. In
some cases, a warmstart may be needed to stop evaluation of
a "circular reference".

Quote:
- 'SQRT 5' 2 + SQ EXPAN COLCT gives back a numerical result
17,94... instead of '4*SQRT 5 + 9'(where SQRT is the square root
character)

True, as documented, COLCT starts out by evaluating numerical
subexpressions.

Quote:
I still like the FORMS editor, it was powerful and a lot faster
than the Equation Editor on 48s.

I tend to agree on that.

Quote:
32 kb is nice to use. So I only wish this model would have
benefited from all the ideas that surfaced in the following years.

Well, that's the nature of the evolution of devices.

Quote:
However, this one was the real innovation, the 48/49 being IMHO
much less of a change in paradigm.

Actually, I'd say that the 28C was the real innovation; it
introduced UserRPL. The changes in the 28S and 48/49 series seem
rather minor in comparison.

Quote:
I think this machine deserves some space in the museum.

Well, it does have some space in the Museum; see
http://www.hpmuseum.org/hp28c.htm. But apparently some feel
that the RPL models don't belong in the Museum at all.

Regards,
James

Edited: 16 Sept 2005, 2:21 a.m.

#22

Nice thread! My first HP was a new 28S my first year of college back in '89. I had four manuals for it and read them all cover-to-cover that Christmas. Although I don't find it very useful at the workplace, it is really at home on a well-lit desk for doing hours of physics or math homework (somewhere it has space to breathe and not be shuffled around). I kept mine (and the manuals) in mint condition all these years and have increased my HP collection. I've hit my 32k memory limit, too, and was really down the day my batteries went south and memory followed (loosing it all!). I'll always have a special place in my heart for the 28S. I only wish I had purchased one of those nice leather covers for it back then! $20 in those days (same as the manuals) and the 28S itself costed me $200!.... back then! Gotta love its RPL, though.


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