<p>I have my HP-67 right in front of me on my desk and I frequently work in a dark room with some light from the monitors but using an LCD calculator would be difficult. We have LCD HP (48 GX or SX) but the kids use that along with their TI models.</p>
<p>The HP-67 has about 224 steps of memory, a motorized magnetic card reader/writer and it came with a library of programs on magstrips. You could buy all kinds of libraries for engineering, statistical and other calculations. The keys today work better than the keys in modern junk. I started realizing how old the calculator was when I started seeing them in museums in the 1990s.</p>
<p>I also had a few Pickett slide rules in the 1970s and one circular slide rule in a rectangular plastic setting. The plastic setting had all sorts of formulas and conversion constants. It was meant to fit in your shirt pocket next to your pocket protector.</p>
<p>There’s a company in Canada that still sells new Pickett slide rules. They buy them from around the world, including Eastern Europe and resell them or auction them off for a nice profit. They are frequently given as gifts to engineering grads. You can have fun with stuff like this in interviews too. Just hand the person that you’re interviewing the slide rule and ask him what it is and how you use it.</p>
<p>Sometimes brute force methods do work. Especially if the table fits nicely in the L1 cache.</p>