HP 9100B  Summary
The HP 9100B is a improved version of HP 9100A, a first Hewlett Packard calculator introduced in 1968. The 9100 is a scientifics desktop calculator with magnetic core memory,
printed circuit board ROM, a CRT display and magnetic cards reader/writer. The 9100 has 32 storage registers and 3levels stack (registers X, Y and Z). The storage registers
are splited in two pages. The pages were labeled + and  and + page was assumed if neither was specified for a store or recall. Each page of core has the 16 registers called 09
and af. The stack and registers can be easy manipulated with many keys. Many mathematical functions are directly available from the keyboard.
The HP 9100 works with floating point BCD (binary coded decimal) aritmetics in a range of 10^{98} to 10^{+99} and never shows more digits after the
decimal than they were set with a rotary switch at rigt for  even on number entry. If is typed a larger number than the display could handle, the HP 9100 automatically switch to scientific
mode. The HP 9100 has two "guard digits" beyond the displayable 10 digit mantissa. This kept the normal floating point errors "out of sight".
The HP 9100B has programming features. A program with max. 392 program steps can be created in RPN. The calculator use line addressing with two digit hexadecimal line
numbers. The "IF" statements could check for less than, equal to or greater than and the lines after the if held a line number that the calculator jumped to if the condition was true.
A single flag and simplified 5 level subroutine capability is available. The program memory is shared between programs and data with each storage register yielding 14 program
steps. The created program is possible to write to a simple magnetic card. The magnetic card uses two tracks, each track has capacity of 196 program steps. The magnetic cards
have size like credit cards. The card is inserted into the slot and it is ejected from the same slot during the read or write.
The HP 9100 has ferrite ROM with capacity of 32 kbits program memory and 1.8 kbits of control memory. The RAM called magnetic core memory has capacity of 4416 bits.
The ferrite memory has an advantage  the calculator can be switched off and on without losing data or programs.
The HP 9100B has 3levels stack (registers X, Y and Z). The bottom is "X" register, accessible from keyboard. In middle is "Y" register, called "accumulator". On top is "Z"
register called "temporary". The content of the registers can be rolled down or up. The content of "X" and "Y" can be alternated with a key.
Price in 1968  1970 was US$ 4,900.

Technical details 
MANUFACTURER 
Hewlett Packard 
YEAR 
1968 
ORIGIN 
USA 
DISPLAY TYPE 
CRT, 3 lines, 10 digits 
ROM 
512 words x 64 bits of program ferrite memory 64 words x 29 bits control ferrite memory 
RAM 
4416 bits 
CPU 
transistors core unit 
FORMATS 
Fixed or Floating point with a range of 10^{98} to 10^{+99} 
LOGIC SYSTEM 
RPN 
STACK LEVELS 
3 levels, X, Y and Z registers 
STORAGE REGISTERS 
32 registers, 2 pages ("+" and ""), each with 0  9 and a  f registers 
FUNCTIONS 
+, , ×, ÷ , abs y, sq. root, int x, LOG x, LN x, e^{x}, π 
GONIOMETRIC FUNCTIONS 
sin x, cos x, tg x, asin x, acos x, atg x, hyp sin x, hyp cos x, hyp tg x, DEG, RADIANS, Polar / rectangular conversions 
PROGRAMMING 
RPN, 392 program steps, 32 storage registers 
I/O PORTS 
expansion port 
POWER SUPPLY 
internal 115V / 220V / 70 Watt 
SIZE / WEIGHT 
406 (W) x 480 (D) x 210 (H) mm / 20.5 kgs 

