HP 35s Review Message #1 Posted by Will Rutherdale on 12 Sept 2007, 12:56 a.m.
I've been using HP calculators for decades and own several. Last summer I tried updating to newer models, and have acquired a 33s, a 50g, and now a 35s.
I want a calculator with a good mix of discrete and scientific capabilities, with a convenient user interface.
After a couple of days of trying the 35s out, I have some comments. These are just my personal usability concerns. I realise the calculator has already been released and probably won't be changed.
This is my first posting here. I hope they formatting comes out okay.
Good
~~~~
 adds logic operators (compared with 33s)
 good notation (i / theta) for entering complex numbers
 nicer keyboard layout than 33s
 good that funny mode keys are gone
 arrow keys are better
 big ENTER key is nice to see again
 better look and feel
 addition of extra units and physical constants is very useful
Problems (in order of decreasing priority)
~~~~~~~~
 forced to fish out the 'h' suffix when entering a hex number,
even when in hex mode
 this is very inconvenient if you want to enter a lot of
hex numbers
 it takes too many keystrokes to get that 'h' suffix, which
should be implicit in hex mode
 user is now forced to enter a mantissa part for a number in
scientific notation
 standard interpretation in HP calculators for decades has
been to default to 1
 for instance 'e2' is taken as '1e2' in older models
 this is a great keystroke saver and has been in place for
decades in all HP calculators, up to and including the 50g
and the 33s
 sanity check: entering the number 1000 in scientific notation
should reduce the number of keystrokes
 sometimes the calculator misses a typed key
 overzealous debouncing?
 sqrt key gives 'invalid data' for complex numbers or negative
numbers entered as a complex number
 inconsistent with general ability to use transcendental
functions on complex
 sqrt is easy to implement in complex
 y^x key does it anyway when you give an exponent of .5
 there is no way to extract real and imaginary parts of a complex
number
 location and labelling of hex digits a to f
 I realise that layout decisions are not easy, but placing
them two rows below the register labels A to D is a bit odd
 assuming they hold to the layout, it would be better to at
least add some special labels in a different colour for
the hex a to f
 additional logic operators would be useful: shift, rotate, etc.
 compare with 16C or 50g
 new vector data type is very thinly supported
 no real power to it, just addition of vectors and
multiplication by a scalar
 it complains on input of a vector of length 0 but not a
vector of length 1
 2*2 lin. solve and 3*3 lin. solve are badly done
 user has to fuss with a list of storage registers
 better idea: let user enter a set of vector objects into
the stack and let calculator operate on those
 for instance, 4 length3 vectors would suffice for input to
a 3*3 lin. solver
 E key (for Enter Exponent) would be better labelled EE or EEX
 this would avoid confusion with the other E keys
 would stand out better
 when complex numbers are displayed in polar form, it would be
useful if the 'theta' character could be rendered differently
so as not to resemble zero and eight so much
 there should be a way to view complex numbers to greater
precision
 see for instance how this is done in the 15C
 also compare with the scrolling view of large binary
numbers in the 35s
Overall Conclusions
~~~~~~~~~~~~~~~~~~~
The 35s has lookandfeel improvements over the 33s and some functionality improvements. However, some interaction issues that affect everyday usage appear to have slipped through.
The 35s ought to be a convenient everyday use alternative to the bigger and more sophisticated 50g, but the 35s has limitations that leave the 50g more suitable for everyday use.
Will
