• HP Computer Program VA010 - A Simple Checkmate Searching Program
  
  
  • 29-page paper featuring a simple, standalone checkmate searching program I wrote in 1998 using a Hewlett-Packard Vectra/MMX @200 Mhz computer which, given a legal chess position, the side to move and the maximum number of moves to give checkmate, it will search and output either a move which checkmates in that number of moves (or less), or the fact that there’s no such move. It can also search for only-checks mates. Eight amazing worked examples are included.
    
    Main features include: full legal move generation (including full legal castling [all 5 mandatory requirements for legality], en passant pawn captures and underpromotions), can find checkmates in any number of moves (up to 64, subject only to available memory and time), can find general checkmates or checkmates in which the mating side gives only checks (this is useful for finding much faster those long sequences of checks that end in checkmate), accepts positions in FEN notation and checks them for legality and syntax, searches for checkmates iteratively starting from "checkmate in 1" and thus always finds the shortest posible checkmate.
    
    While searching, it shows progress and time taken for each iteration and the search can be halted immediately at any moment by simply pressing a key. Otherwise, when the search ends it outputs the first move found that gives checkmate in the specified number of mover (or less) or the fact that one doesn't exist, the final total time for the search and the number of nodes examined.
    
    Last but certainly not least, the whole source code is included, fully commented, easy to understand (no obscure, tricky code) and written in a didactic fashion to help study and use in your own chess-related programs.

• HP Program VA415 - HP-41C Systems of 1st-order Differential Equations
  
  
  • 7-page paper featuring a 137-step program for the HP-41C programmable calculator to obtain quickly and accurately an approximate numerical solution for a system of N simultaneous first-order differential equations or, conversely, a single differential equation of the Nth-order, using a fourth-order Runge-Kutta method. It will also run on the HP-41CV, HP-41CX and the HP42S. Two worked examples included.

• HP Program VA345 - HP-34C Nonlinear Equations Systems
  
  
  • 4-page paper featuring a 102-step RPN program for the HP-34C programmable calculator to solve a system of two arbitrary nonlinear equations in two variables. Will also work as-is on the HP-67, HP-97 and HP-15C, and on the HP-41C series and the HP42S with minimal changes. Two worked examples are included.

• HP Program VA346 - HP-34C Factoring-GCD-Decimal to Fraction
  
  
  • 3-page paper featuring a 127-step program for the HP-34C programmable calculator to factorize an integer into its prime factors, compute the greatest common divisor (GCD) of two integers, and find integer fractions which best approximate a given real value. It will also work in the HP-41C series and other HP RPN calculators with trivial changes. Three worked examples are included.

• HP Picture VA152 - HP-15C
  
  
  • This is one of my HP-15C, the most capable Voyager Series model, a real marvel of engineering with the best ergonomys and [...].

• HP Picture VA415 - HP-41CX
  
  
  • This is my HP-41CX, the best classic version of the HP-41C, a revolutionary alphanumeric model every HP-calc fan craved for [...]

• SHARP Picture VA245 - SHARP PC-1246 Manual (as Tandy PC-8)
  
  
  • This is the Operation Manual for my SHARP PC-1246 pocket computer (as Tandy PC-8) [...].

• SHARP Picture VA510 - SHARP PC-1500A Applications Manual
  
  
  • This is the Applications Manual for a SHARP PC-1500A, a machine very similar to my TRS-80 PC-2, an extremely popular pocket computer [...]

• Other Picture VA019 - CASIO fx-7500G Manual
  
  
  • This is the Owner's Manual for my CASIO fx-7500G, a most awesome scientific programmable graphic calculator released in 1989 [...]

• SHARP Thread VA000 - Yes I know it is a TI

• SHARP Thread VA001 - Commodore and Sharp calculators

• SHARP Thread VA002 - Manuals wanted Sharp PC-1250A

• Misc Picture VA117 - Sacred Scarab                       {Old Egypt's Sacred Scarab. The resemblance is uncanny.}

• Misc Picture VA190 - Omaha Beach Bunker            {Bunker at Omaha Beach on D-Day, firing and being fired at.}

(12-12-2019 02:20 PM)Ángel Martin Wrote:  This one is particularly rich, an early Christmas edition perhaps? ;-)

(12-12-2019 05:11 PM)Valentin Albillo Wrote:  I wonder if once I've uploaded a sufficient number of my HP-41 programs you'll be tempted to create one of your wonderful ROMs, say the "Albillo ROM". What say ?

(12-13-2019 06:16 AM)Ángel Martin Wrote:  

(12-12-2019 05:11 PM)Valentin Albillo Wrote:  I wonder if once I've uploaded a sufficient number of my HP-41 programs you'll be tempted to create one of your wonderful ROMs, say the "Albillo ROM". What say ?

Consider it done ;-)

Have a great break, y claro está, una feliz Navidad para ti y tu familia.