magill (10/20/82)
Has anyone noticed that people who learn to use an HP never go back to TI and that the only people that don't like HP have never learned to use them? I'm speaking of scientific calculators not desktop or "micros". Rich Magill
al (10/21/82)
I guess I must not be a 'people' because I first owned an HP-65 and loved it but then went on to an SR-52 (which had a terrible card reader) and finally to a TI-59.
kline (10/21/82)
#R:cwruecmp:-18500:uicsovax:3700041:000:579 uicsovax!kline Oct 21 10:43:00 1982 No kidding! Even a fairly non-engineering/mathematically oriented girl I know has been singing the praises for RPN ever since she acquired an HP calculator. And yet a lot of CS majors I know still refuse to use any calculator which lacks an '=' key. I made the switch to HP three years ago, and I know I'LL never go back to TI's "AOS" or whatever they call it--it's too confusing for me to remember all those parentheses, and you aren't given any indication of where you are in the expression should you forget where you left off in the middle of entering a long calculation.
BYTE@Mit-Mc@sri-unix (10/21/82)
From: Roger L Long <BYTE@Mit-Mc> I was brought up (went through High School and two years of college) with a HP-35 and then a HP-45. When TI came out with their TI-Programmer, I bought it - not because I especially like TI calculators, but because it was all that was available. Recently, HP introduced their model 16-C and it took no effort at all to toss the TI-Programmer into a drawer to gather dust and go out and purchase the 16-C. Although the 16-C is about twice as expensive as a TI-Programmer, it is an order of magnitude or so more powerful. But the only feature that prompted me to switch was that HP makes keyboards that don't bounce. The TI's keyboard bounced mst of the time that I had it. Other TI's that I've used also have cheap bouncy keyboards. If it weren't for me being sick and tired of having to re-enter (and re-enter and re-enter and re-enter) numbers and calculations on the TI, I would have probably kept it for awhile longer. The 16-C's a beauty. Thank-you HP! -roger
Heiby.APSE@Hi-Multics@sri-unix (10/21/82)
Never use a sentance that contains the word "never"! The first scientific calculator I really used was an HP-35. Now, I use a TI-59. Granted, the only reason is that my employer gave it to me free for learning how to use it and I'd use an HP if I could, but I don't think it's really a bad machine at all and does have some features to recommend it. Ron.
mwm@Okc-Unix@sri-unix (10/21/82)
From: Mike Meyer <mwm@Okc-Unix> No, I haven't noticed that people who learn to use an HP never go back to a TI. I'm a counterexample. About 7 years ago when I was looking for a calculator, I looked at both the TI and the HP, and got capable with both. I can still use an HP if I need to. At that time, calculators were obsoleting in about a 6 month interval, and I didn't consider the extra bucks HP wanted to be a worthwhile investment. Just recently the calculator I got then began to flake out, so I went shopping for another calculator. This time, I looked at HP (the 16C), TI, Sinclair, and others. I eliminated TI (poor price/performance ratio compared to sinclair), and was debating between the 16C (it's price performance ratio is comparable to my programmer, but it is also usefull in a non-programming situation, which the programmer isn't) and a couple of sinclair models, when a friend offered me his used 59 at a GREAT price. Pounce. When I consider RPN vs. algebraic, it comes down to one thing: less trouble going from programming to using the caclulator (exceptions being lisp, forth, etc). This compensates almost exactly with the sometimes longer keystroke sequences on the algegraic machines, so I'm willing to consider either flavor. I did just have a thought: a lisp flavored calculator. Or, if you will, an enter/= machine. The keystroke sequences would be: <op><number><enter><number><enter><number><enter><number>=, or some such. Obviously, you could replace a <number> with another such sequence. Has anybody ever built such a beast? I'd like to see one; it could be interesting. Also, it should normally require fewer keystrokes than an RPN calculator. mike
eric@sri-unix (10/22/82)
I have one of TI's new LCD Programmer calculators. The keyboard has a very bad bounce which makes it a real pain to use. Since I am partial to HP calculators anyway, after reading the favorable reviews of the 16C that have appeared on the net, I am thinking about purchasing one of these. Eric Smith (decvax!microso!altos86!eric)
GEOF@Mit-Xx@sri-unix (10/23/82)
From: Geoffrey H Cooper <GEOF@Mit-Xx> Another exception. I started out using RPN on an HP-21. When cheap calculators with infix operators came out (I always but cheap calculators, since I can use a computer for expensive things) I readily dropped any pretense of love for explicit stacks. I now use a CASIO pseudo-programmable (keystroke memory with a return-to-beginning statement). It has a more user-oriented view to numbers. It does DMS notation as well as fractional. I've managed to program almost all of the functions that it doesn't have, including decimal to octal conversion. On the programmable line, I'm surprised that no one has mentioned the pocket basic computers. I would think that they would be the easiest to use, and all have constant memory. Geof Cooper -------
kline (10/24/82)
#R:cwruecmp:-18500:uicsovax:3700043:000:624 uicsovax!kline Oct 24 04:10:00 1982 "...should normally require fewer keystrokes than an RPN calculator." I disagree here: To add 2 and 2, you'd have to say "+ 2 E^ 2 =" on your prefix machine, but I'd only have to say "2 E^ 2 +" on my postfix (RPN) machine. (E^ = ENTER key). And to add a string of numbers, say 1 through 10, you'd have to say "+ 1 E^ 2 E^ 3 E^ 4 E^ 5 E^ 6 E^ 7 E^ 8 E^ 9 E^ 10 =", but I'd write that "1 E^ 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 +", once again saving a keystroke. In general, your scheme for a lisp-like calculator will always require one extra keystroke for every "recursive call," if you will, to evaluate a subexpression.
wsm (10/26/82)
RE: HP durability vs. TI economy I have had three scientific calculators. My first was an HP-25. I loved it, and used it happily until the temptation grew too great to get a machine which I could save programs with. So I got a TI-59. What a piece of user-unfriendly s**t! My biggest problem was remembering which OP # did what (there were about 40 of them) and convincing the card reader to work if not used every day. It broke twice, once under warranty, and once not. I now own an HP-41C, and what a difference! I works perfectly, is very well human engineered (just spell out the function if it isn't on the keyboard) and I have yet to have to clean the cardreader even after weeks of disuse! At my school, we also had a "calculator show", and the HP representative did, at one point in an argument with some smart-ass student who knew the HP's were just overpriced, said "You're right, this is a piece of overpriced trash." At that point he took his calculator (an HP-21) and hurled it at the nearby brick wall. After it bounced a few times, somebody managed to step on it. He went and got it back, proved that it worked, and then asked the student to "try THAT with your cheap TI!" Walt Morris BTL-MH ...mhtsa!mh3bs!wsm (ENTER > EQUALS !!)
Li@Rutgers@sri-unix (10/27/82)
From: Tony <Li@Rutgers> A little story for those of you concerned with the relative reliability of these two brands. A couple of friends of mine, on a dare, both removed their battery packs from their calculators, and held them under water for one full minute. One was a TI-59, the other an HP-41C. After mucho time under the hair dryer, both calculators were plugged back in. The TI worked, the HP didn't. I think that the only thing that this proves is that some of my friends are pretty juvenile. Tony <Li @ Rutgers> -------
mwm@Okc-Unix@sri-unix (10/27/82)
From: Mike Meyer <mwm@Okc-Unix> Yes, if you are doing simply things like op to a string of digits. But lets look at something interesting, like summing the squares of a string of digits. The Lisp machine does: + x2 1 ^ 2 ^ 3 ^ 4 ^ ... 8275 = = (assuming that you don't have a generic finish them off...), whereas the RPN machine you have: 1 x2 2 x2 + 3 x2 + ... requiring about twice as many keystrokes. For random problems, I'd guess they would come out about even (with the close bracket). For doing stat-like things on a long list of numbers, the Lisp machine wins. Of course, you'd program the HP for that anyway... mike
CSvax:rlh (10/28/82)
I must confess that I like the Hp's over the Ti's but I wish they made a reliable battery pack for their(Hp) machines. I have a old hp25 I got back when they were new and I find my self buying a new set of nicads about once a year. The biggest problem with this is that the Hp25 won't work if the battery pack goes out, so you can't plug it in unless you buy a new one. I have noticed that they rate at which they die doesn't depend on how much they are used or how often they are charged. I have tried always waiting till they or run down, as the users manauls suggest and many other techniques. Is it possible to bring a pack back to life? The lasted dead pack has one shorted cell and one good one. If I can find and another one I might try surgery but I am getting tired of shelling $10 - $12 buck each fall. Is there a trick with a diode or something to get the hp25 to work without the battery? Rich
ARPAVAX:Onyx:harymudd (10/28/82)
Of course, another thing to add to that is the way I tend to treat my CASIO fx-68 (the pocket model in the Al case). I frequently use it as a door jam, among others things. It seems to hold up. Someday I might try the wall-and- stomp test, if I get the nerve, since I do have spares...
lmg (10/28/82)
I always thought the HP battery packs were reliable, just a little short on capacity. My HP-45 (circa 1974) is still running strong on it's original pack. My HP-67 (circa 1978) likewise. The three hour charge - fourteen hour recharge cycle is what bothers me. Larry Geary Bell Labs, Holmdel ...npois!houxi!hosbc!lmg
twk@sri-unix (10/29/82)
When I was an undergraduate, I knew two people who had been assigned together as roommates: and of course, they didn't get along too well... One friday night after some partying, one of them threw the other's calculator into a bucket of water. Rather than removing it, the other person threw the first person's into the same bucket. When they were retrieved, it turned out that only (you guessed it) the HP functioned; the TI was dead. I guess rutgers isn't the only school populated by juveniles... Tom Kronmiller HP Design Aids Lab ...ucbvax!hplabs!hpda!twk ...sri-unix!hplabs!hpda!twk
yin@sri-unix (10/30/82)
the problem with the battery packs is that ni-cads are really lousy
and unreliable. you can improve the life by following the suggested
charging and discharging procedures, but there's not much you can do
beyond that. i've gotten shorted cells to come back to life by zapping
them with a 25 amp power supply and burning out the short, but the
cells usually shorted again in another month or so.
besides the typical full charge and discharge cycles recommended by
manufacturers, versus the continuous trickle charge that most users
subject their battery packs to, it also helps to do an occasional deep
discharge cycle. i.e. take the pack and load it with a resistor of an
ohm or two and allow it to discharge at a high rate. keep track of cell
temperature, don't let it get too hot to touch (say 60 deg. C), monitor
cell voltage, the voltage should not drop below about 1.0 volt per cell
(nominal ni-cad voltage is about 1.2 volts). do this until the voltage
stays low, there will be some springing back, and then recharge to a
full level. don't allow it to get completely discharged or one of the
cells may reverse.
you might also consider breaking the pack apart and replacing the cells
in the pack with GE ni-cads. my experience has been that GE really has
the technology down pat and they produce longer lasting, more reliable
and more consistent cells. they cost more, but they seem to be worth it.
i doubt that there is a reasonable fix to the calculator that will allow
you to run just on the charger. i've been told that the power circuits
in the hp calculators use the battery pack as a voltage regulator. also,
typical trickle charger current is about 1/10 of the pack capacity and the
calculator usually charges the pack in about 12 hours and discharges it
in about 3 hours. this suggests that charge current is only about 40%
of typical operating current. i don't know if the charger has the capacity
to make up the difference if you were to try and put it directly on line.
yin shih
megatest, santa clara
gsw (10/30/82)
Two years ago this December I purchased an HP-34C after hearing of
the power of RPN and of the HP line in general (this all came from a
math teacher who is a real HP fan ... he actually would take a day or
two off from the normal class schedule to explain RPN and, of course, HP's.)
Although it costed about $135 at the time, it has paid for itself without
a doubt and I will NEVER go back to TI.... I do have one complaint about
the quality and durability of HP's that seems to contradict what others
have been saying. After about one year I began to experience a problem
with the HP-34C line that others have had. Every so often, A digit or two
would disappear or it would suddenly switch to program mode.... nothing
a few hits on its side wouldn't fix. This problem is probably caused by
bad connections made with the display contacts and switches... I was very
upset, needless to say, when this started occuring, and it hasn't got any better.
Although this would seem to be enough to loose faith in HP's, I still prefer
them over any other brand of calculators.
I would suggest that if anyone is going to get a calculator,
1) do not get the HP34C, and furthermore,
2) get one with an LCD display....
One question: does anyone know of a quick fix to the HP34C
problem,.. like send it back to HP (is it worth it?) ?
Gregg Whitcomb
mcnc!gswjon (11/01/82)
#R:purdue:-42300:hp-pcd:6200010:000:313
hp-pcd!jon Nov 1 09:29:00 1982
Note that the newer HP machines are entirely CMOS with LCD
displays. This allows for long life throw away batteries.
HP-41C users with card readers can buy an optional ni-cad
pack. (Of course, you dont really need a card reader, or
even a 41C, to buy the ni-cads.)
Jon Brewsterdoehring (11/03/82)
Well, I don't know about making it work without the battery pack, , but there are many things you can do with nicad batteries. The thing that you mentioned about letting them die down all a the way is to get rid of their "memory". They tend to "remember" how much they were used and then can only give out that much energy, i.e. a 500mah battery which is used so that only, say, 250mah are used much of the time, then only 250mah is available. Since you seem to be spending a lot of money on batteries, you might be interested in buying/making something to fix these batteries. I am interested in radio-control airplanes and we run into this problem a lot. There are devices on the market which will "cycle" nicads and tell you how much capacity they have, and maybe get rid of the memory. You can also get/make devices which can bring back to life some dead cells, it "zaps" them with a higher than normal voltage which helps shorted cells. You can also buy sincle batteries of just about any normal size for reasonable prices from people who advertise in modeling magazines. You should check back issues of RCM ( Radio-Controlled Models ) for schematics on devices of this type and/or discussions concerning rechargable batteries of many types. ( also Model Builder, and other similar mags are helpful ). I am writing much of this from memory and so if I made some mistakes, please forgive me, it's been a long time. Martin S. Doehring decvax!yale-comix!doehring doehring@YALE