Emu75/DOS
is a software emulator of the
HP-75C machine and HP-IL system.
It runs under DOS or in a command box under various 32-bit Windows
(98,2000,XP,...).
It can run on 64-bit OS using a virtual DOS environment (see below).

Note: in all this document, Emu75 means “Emu75/DOS”.
Emu75 Documentation (pdf file)
Emu75 1.33 Freeware Package without ROM images – May 2022
Emu75 Source Files released under GNU Public Licence
Emu75 uses ROM images of HP-75C ROM and modules (Math, I/O ROM, ...).
To help you to quick start Emu75, you will find here the necessary images of the HP-75C machine. Although I don't have a formal authorization from the Hewlett-Packard company, I considered that this is consistent with the publication by HP of the source listings of these ROM. If it happens that the Hewlett-Packard company should be opposed to this, I would immediately remove these files from my site. Don't ask me to provide other HP or third party ROM images.
Running Emu75/DOS on 32-bit Windows systems
Emu75/DOS
runs fine in the Command box on 32-bit Windows system.
On some Windows OS versions, the keyboard localisation is no properly
configured when running 16-bit DOS programs – for instance on my French
Win7 machine, the keyboard is responding as QWERTY instead of AZERTY inside
Emu75.
To solve this problem, use the kb16 command (present in the Windows System32
folder), for instance "kb16 fr" for a French keyboard. You can add
the kb16 command in a batch file, or add it to the autoexec.nt file (also in
the Windows System32 folder).
It may also be needed to switch to the EN keyboard layout (Shift-Alt) to have
access to the Alt-Gr characters.
Running Emu75/DOS on 64-bit Windows systems
Since most bare 64-bit Windows OS versions don’t support 16-bit DOS applications anymore, a virtual environment must be used.
DOSBox version 0.74 has been successfully used to run Emu75/DOS on a Win10-64 bit system.
This DOS Utility (author unknown) can be used to expand the DOSBox window from 25 lines to 50 lines (or 40/66 lines, at your option). Extract the 8x12_50.com (or other settings) and 8x12.fnt to your working folder.
I personally renamed the 8x12_50.com command to mode50.com for easy typing at each new DOSBox session.
Emu75/DOS
includes a native support of the PIL-Box,
which works “reasonably” well on native DOS, Win98 or Win2K
systems.
These systems are now obsolete and Emu75/DOS has to run in a virtual DOS
environment on modern 64-bit OS, making this native support no more effective.
I now
recommend to use the ILPer software in
conjunction with the PIL-Box as a gateway between Emu75/DOS and a real HP-75C/D
for program/data exchange.
This is done by sharing the same virtual drive HDRIVE1.DAT in Emu75/DOS and
ILPer.
LIF archives can be found on the Web. Here are my personal HP75 software collection (no doc, sorry):
Here are two volumes from the HPCC library with HP75 resources (again, no doc):
To use an archive, unpack it to put the LIF file image (size should be about 630K) to some directory, and declare the path to this file in HDRIVE1 or HDRIVE2 declaration (Emu75.ini file). Example: HDRIVE2 hp75_2.lif
You can find other archives, including the CHHU and SWAP collection, at The Museum of HP Calculators FTP and on the Joseph Horn Online LIF Disk Project.
A lot of internal technical documents can be found on the HP-75 group page.
Reversi is a classic board
game. The HP-75C version below is based on an adaptation of a HP-85 program I
made for the HP-71B around 1985, with minor changes for Emu71 done in 2003, and
adapted again for Emu75 in 2017.
It runs great on my Emu75/DOS in a 43- or 50-line mode command box on my old
Win2k system, or in DOSBox in 40-line mode (or better). The screen size is too
small to run it in Emu75/DOS in a normal 25-line mode.
Reversi on Emu75/DOS
Reversi program for the HP-75C on a LIF disk image
The original HP-85 game and documentation can be found here: http://www.series80.org/Programs/HP85-GamesPac/index.html
More specific links about the HP-75C and HP-80 series
J-F Garnier, 2022