Radio Shack PC-4

Datasheet legend
Ab/c: Fractions calculation
AC: Alternating current
BaseN: Number base calculations
Card: Magnetic card storage
Cmem: Continuous memory
Cond: Conditional execution
Const: Scientific constants
Cplx: Complex number arithmetic
DC: Direct current
Eqlib: Equation library
Exp: Exponential/logarithmic functions
Fin: Financial functions
Grph: Graphing capability
Hyp: Hyperbolic functions
Ind: Indirect addressing
Intg: Numerical integration
Jump: Unconditional jump (GOTO)
Lbl: Program labels
LCD: Liquid Crystal Display
LED: Light-Emitting Diode
Li-ion: Lithium-ion rechargeable battery
Lreg: Linear regression (2-variable statistics)
mA: Milliamperes of current
Mtrx: Matrix support
NiCd: Nickel-Cadmium rechargeable battery
NiMH: Nickel-metal-hydrite rechargeable battery
Prnt: Printer
RTC: Real-time clock
Sdev: Standard deviation (1-variable statistics)
Solv: Equation solver
Subr: Subroutine call capability
Symb: Symbolic computing
Tape: Magnetic tape storage
Trig: Trigonometric functions
Units: Unit conversions
VAC: Volts AC
VDC: Volts DC
Years of production:   Display type: Alphanumeric display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 3"×6½"×½" Display size: 12 characters
Weight: 4 oz    
    Entry method: BASIC expressions 
Batteries: 2×"CR-2032" Lithium Advanced functions: Trig Exp Cmem 
External power:   Memory functions:  
I/O: Printer port     
    Programming model: BASIC 
Precision: 12 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 26(0) numbers Program display: Text display  
Program memory: 490 bytes Program editing: Text editor  
Chipset: Casio PB-100   Forensic result:  

pc4.jpg (26569 bytes)Having worked with the venerable TRS-80 back in the good ole' days, I expected a "Radio Shack Pocket Computer" that is actually marked TRS-80 to be a machine that's closely compatible to Radio Shack's hugely successful one-time desktop product line. Instead, I was somewhat disappointed to find yet another OEM Casio calculator.

Not that there's anything wrong with these Casio machines. They were popular for a reason: they're well built, robust little machines with a solid hand-held implementation of the BASIC language. (That said, I still have some reservations about the notion of using BASIC in a hand-held device designed for ad-hoc programming, as I commented in the case of the HP-75C, for instance.)

So here's yet again this somewhat boring example, a Gamma function program:

100 INPUT "X=",X
110 T=1
120 IF X>=0 THEN 160
130 T=T*X
140 X=X+1
150 GOTO 120
160 G=1.00000000019
170 G=G+76.1800917295/(X+1)
180 G=G-86.5053203294/(X+2)
190 G=G+24.0140982408/(X+3)
200 G=G-1.23173957245/(X+4)
210 G=G+1.20865097387E-3/(X+5)
220 G=G-5.39523938495E-6/(X+6)
230 G=LN (SQR (2*π)*G/X)
240 G=G-X-5.5+LN (X+5.5)*(X+.5)