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What do you keep on your 42S?
10-23-2019, 03:42 PM
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What do you keep on your 42S?
I've had a DM42 for about 2 years now, and I finally got a "real" 42S last month. It's making me appreciate squeezing every last byte out of that little 8 KB RAM chip, and also realize how much I take the huge memory of the DM42 for granted!

Those of you with a 42S, what do you keep on there as your (semi-)permanent loadout? I've managed to cram all this into mine so far:

- GCD, LCM, Floor, Ceiling, Reduce fraction
- Fractional approximation ( - much smaller than QPI, and I don't need the pi or radical approximations it offers
- Factor - the venerable mod 30 sieve I implement on everything
- IO Record - for tracking fluid input/output during the week (my doctors make me do this), uses about 11 matrices for data storage
- A couple solver programs for doing IV rate calculations
- Natural logarithm of gamma - adapted from here: (reasonably accurate for any arguments that would overflow the built-in GAMMA)
- Binomial probability distribution (uses the log gamma function to handle extremely large inputs)
- Negative binomial probability distribution
- Hypergeometric probability distribution
- TVM solver program
- Unit conversions: length, area, volume, mass, temperature, speed, pressure (each handles 4-8 different units that I use often enough to want on here); these are based on the program design in 42S Mechanical Engineering
- Resistor color decoding/encoding - tweaked version of, and an ohms-to-color program that I can't remember if I found somewhere or wrote myself
- IP address calculator - does subnet conversion, finds broadcast addresses, calculates number of hosts in a subnet, etc. (probably coming soon to the software library forum)
- Date calculations (can't remember where I found these programs)
- Speed-of-sound solver program - based on formulas here:

And somehow I still have 1,457 bytes free! Right now I'm running SIZE 0030 with real REGS. I might try to fit the triangle solver from the 32S Engineering Applications book. If I can keep around 1 KB free, that should be enough for any transient data/programs I need to work with temporarily.

What do other 42S users like to spend their RAM on? With as much as I paid for it, I'm not quite brave enough to crack it open and put in a 32 KB RAM chip, but if (heaven forbid) I ever have to open it up for repairs, I might try upgrading the RAM while I'm in there.
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What do you keep on your 42S? - Dave Britten - 10-23-2019 03:42 PM
RE: What do you keep on your 42S? - Trond - 11-01-2019, 02:51 AM

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