|Re: OT: Does anyone own an APF mark 55?|
Message #26 Posted by Michael de Estrada on 19 Mar 2009, 11:20 p.m.,
in response to message #20 by Palmer O. Hanson, Jr.
Yes, I was aware of the M+x^2 capability of the 4510 and 4615, but db had stated that the NS/Novus calculators have a stat function that HP *never* did have. As you point out in your article, although the HP-45 did not have a M+x^2 key, it provided this automatically with the summation key, and also had the mean and standard deviation on the keyboard as well. Still, the NS 4510 was a direct competitor for the HP-35, and to that extent it was ahead of the game. Also, it has an x^2 key, M+ and M- keys, and can switch between degrees and radians, which are lacking on the HP-35.
The NS 4640 is a very strong competitor to the HP-45 with all its features, and true units conversions similar to the HP-55. Another neat feature is a "clear shifted function", so if you accidentally hit the shift (F) key, you can immediately follow it with the shifted function "CF" to cancel this action. It wasn't until much later that HP introduced toggling of the shift function keys. Unlike the 4510 and 4615, it has a 4-level stack, with cyclic roll down. It's only serious flaw is that it has only 3 storage registers, and these are all used by the summation function to store sum x, sum x^2 and n count. The HP-45 has 9 storage registers.
Edited: 20 Mar 2009, 12:43 a.m.