Looking for the JIMROM 1H

[Didier Lachieze]

For historical reasons I'm looking for the ROM that came with the HHP-16K 41C ROM Emulator designed by Jim DeArras in 1981.
The HHP-16K came with a set of EPROMS containing the JIMROM 1H.

I've not been able to find any copy of this rom on the usual repositories.

So I would like to know if someone still have this EPROM set and would like to share their content.

[Sylvain Cote]

Gerry Schultz had in 2007 a HHP-16K unit with the JIMROM and the documentation → HERE

[Didier Lachieze]

Thanks Sylvain, I’ve sent a mail to Gerry. In the meantime if anybody has a way to access to the JIMROM EPROMs image I’m very interested.

[derekamos]

Hi Didier,
Seeing your dilemma, I had a quick look at my old bunch of ROMs, I did not find the old JIMROM 1H, but did find that this one has many of the same routines:
FILE FORMAT: MOD1
TITLE: PPC/MELBOURNE ROM
VERSION:
PART NUMBER:
AUTHOR:
COPYRIGHT (c)
LICENSE:
COMMENTS:
CATEGORY: Custom peripheral
HARDWARE: None
MEMORY MODULES: 0
EXENDED MEMORY MODULES: 0
ORIGINAL: Yes - unaltered
APPLICATION AUTO UPDATE: No - do not update this file
NUMBER OF PAGES: 1

ROM NAME: PPC-MELB
ROM ID: PR2C
PAGE: May be in more than one location
POSITION: Any page 8-F
PAGE GROUP: 0 - not grouped
BANK: 1
BANK GROUP: 0 - not grouped
RAM: No
WRITE PROTECTED: No or Not Applicable
FAT: Yes
XROM: 12
FCNS: 38
XROM Addr Function Type
12,00 C50A PPC ROM 2C 4K MCODE Programmable
12,01 C55D X<>ROM 4K MCODE Programmable
12,02 C56B Y<>T 4K MCODE Programmable
12,03 C576 Z<>T 4K MCODE Programmable
12,04 C581 Y<>Z 4K MCODE Programmable
12,05 C58E BCDBIN 4K MCODE Programmable
12,06 C59D GTOROM 4K MCODE Programmable
12,07 C5A2 RXR 4K MCODE Programmable
12,08 C5AA RXL 4K MCODE Programmable
12,09 C5B2 X+Y 4K MCODE Programmable
12,10 C5BE SXL 4K MCODE Programmable
12,11 C5C7 NSTO 4K MCODE Programmable
12,12 C5E3 NRCL 4K MCODE Programmable
12,13 C50D TP 4K MCODE Programmable
12,14 C535 VP 4K MCODE Programmable
12,15 C602 CODE 4K MCODE Programmable
12,16 C63F DECODE 4K MCODE Programmable
12,17 C683 EN 4K MCODE Programmable
12,18 C6C2 DE 4K MCODE Programmable
12,19 C707 CLPV 4K MCODE Nonprogrammable NULLable
12,20 C71E XROMTST 4K MCODE Programmable
12,21 C7C4 MELBROM 1A 4K MCODE Programmable
12,22 C7CA PSIZE 4K MCODE Programmable
12,23 C803 PPACK 4K MCODE Programmable
12,24 C808 DIS 4K MCODE Programmable
12,25 C857 2-D 4K MCODE Programmable
12,26 C867 1-D 4K MCODE Programmable
12,27 C88A KEY 4K MCODE Programmable
12,28 C898 PKEY 4K MCODE Programmable
12,29 C8A1 X>Y?? 4K MCODE Programmable
12,30 C8AD CHR$ 4K MCODE Programmable
12,31 C8BA NUM 4K MCODE Programmable
12,32 C8DF RDEL 4K MCODE Programmable
12,33 C8F4 R$ 4K MCODE Programmable
12,34 C8FF L$ 4K MCODE Programmable
12,35 C91C LDEL 4K MCODE Programmable
12,36 C928 RHASTO 4K MCODE Programmable
12,37 C935 CLRKEY 4K MCODE Programmable
INTERRUPT VECTORS:
Pause loop: 000
Main running loop: 000
Deep sleep wake up, no key down: 000
Off: 000
I/O service: 000
Deep sleep wake up: 000
Cold start: 000
CHECKSUM: 16C (Correct - Same as Computed Value)
According to that old Gerry Schultz post, it noted some routines as 'SXL, NSTO, NRCL, TP and VP. These routines look pretty simple but there is a long letter at the end of the documentation from John McGechie written on January 12, 1982.'
Which are all on the PPC/MELBOURNE ROM, I hope this helps. DA

[Didier Lachieze]

Thanks Derek, yes I'm aware of the PPC-MELB ROM, which is a derivative of the JIMROM with added functions from the PPC members in Australia. There is also the Melbourne ROM that was created before the PPC-MELB.

These roms while being built from the JIMROM that came with the HHP-16K don't seem to include an exact copy of the JIMROM m-code even if they include almost all the JIMROM functions. At that time m-code was pretty new and people were experimenting with it, burning new EPROM versions quite regularly.

So I'm still looking for the original image of the JIMROM 1H.

[Joe Horn]

Have you tried contacting Jim DeArras himself? He's no longer active in the HP calculator user community, but he's very much alive (and very active on Facebook), still lives in Virginia, and he might have kept a copy of his own software. PM me for contact info (I will not post it here).

[Didier Lachieze]

Thanks Joe, PM sent.

[Didier Lachieze]

My quest for the elusive JIMROM has come to an end. I recently got an HHP-16K 41C ROM Emulator containing the original JIMROM EPROM set. The image of this ROM which is AFAIK the first ever mcode user ROM is now on its way to the well known hp41 repository.

[Jurgen Keller]

(06-21-2024 02:14 PM)Didier Lachieze Wrote:  My quest for the elusive JIMROM has come to an end. I recently got an HHP-16K 41C ROM Emulator containing the original JIMROM EPROM set. The image of this ROM which is AFAIK the first ever mcode user ROM is now on its way to the well known hp41 repository.

Thanks for your efforts to preserve this ROM! Did you also succeed to get the documentation referenced in the post by Gerry Schultz?

[Didier Lachieze]

I don’t have the original documentation provided with the HHP-16K for this ROM, however using John Mc Gechie articles in PPC TN, as well as other sources I documented the different functions from the JIMROM, the Melbourne ROM, the PPC ROM 2 and the TOULROM as they share the same origins: JIMROM > MELBOURNE > PPC ROM 2 > TOULROM. I’ve also sent this document to Warren.

[rprosperi]

Well done Didier, nice work to capture a truly rare beast in the wild!!

Also, nice analysis to have determined the genesis and evolution of these early MCODE projects, filling in some gaps in this formative stage of 41 exploration.

[Didier Lachieze]

The files are now available on Warren’s site.

[PeterP]

This is amazing stuff, Didier, thank you so much for preserving and sharing this with everyone!!

[Namir]

(06-23-2024 05:47 PM)Didier Lachieze Wrote:  The files are now available on Warren’s site.

Merci Didier!!! Awsome to download these ROM. Jim deArras was my best man in my first wedding. Sadly we lost contact over the years.

Namir