HP-95LX Programming


Hi all,

I've just won an eBay auction for an HP-95LX. I probably would never have bid on it if it weren't for the enthusiasm about those HP old school "pocket PCs" on this forum! :-)

Of course, I'll have to wait and see just what kind of condition that machine is in, but assuming it works OK, I think I would like to try programming it -- meaning: to port some of my existing C/C++ programs to run in its DOS environment. Can anyone recommend any tools I might be able to use for that kind of work?

I have used DJGPP and RHIDE for DOS development in the past, but I think those tools are targeted to the 386 or later, and the 95LX only has a 8086 (or is it a 80186? I don't even know how they differ...).

I'm not looking to run the development tools themselves on the 95LX; I'm just looking for something that will generate code that can run on one. A C++ compiler would be really sweet. :-)

- Thomas


I have Turbo Pascal and Turbo C running on my 200LX, but I'm not sure if those will run on the 95LX. The memory may be too small, and I had quite a bit of trouble getting a decent size flash card to work on my 95LX (my 200LX has a 256 MB crucial card--big enough for all my DOS stuff.)

I made the mistake of getting a 95LX first and not being able to do much with it. You may want to keep an eye out for a 200LX 2MB or 4MB model; quite a bit more versatile.



Well you can run the Turbo Pascal and or Turbo C on a PC and then run the compiled program on the 95LX.


Try: http://www.openwatcom.org/

You can install on Windows and cross compile 16 bit binaries for DOS.


I have not tried them on a 95LX, but Borland's Turbo C++ for DOS used to be hugely popular (almost a defacto standard), and it can target the 8086/80186:
It is now freeware

and you could no doubt pick up the full version with manuals etc on eBay for next to nothing if you want.

There is also the freeware HI-TECH Pacific C compiler:
but it's not ++



Hi Thomas,

Congratulations on your HP-95LX. That was my first PDA. I had the 512K version, then had HP upgrade it to 1 MB and then went to the HP-200LX and still use it.

I agree with Chuck that you'll probally want to eventually get the HP-200LX, but there is a lot that can be done on the 95LX.

I just went over my old copies of the HP Palmtop Papers on disk and found PCC, which is a C compiler that is supposed to run on the 95LX. It's shareware so I could send you a copy.

You don't say whether you getting manuals with it, but manuals can be found at:

HP-95LX Manuals

There's some good technical info at:

HP-95LX Technical Information

Definetly check out the Palmtop Paper:

Palmtop Paper

You'll want to browse the early issues which have lots of info on the 95LX.

Don't forget the SuperSite:


Do a search for 95lx and grab the SUNDRV files. These will let you use up to 32mb ATA flash cards with the 95LX. Otherwise, you'll need to get SRAM memory cards, which are limited to 2 MB.

Not sure if there was a 95LX developer's package. I do have the developers package for the 100/200LX which lets you create System Manager (EXM) compliant programs using Borland C++.

Have Fun.


Edited: 5 Sept 2007, 7:12 a.m.



Special thanks to you (and the maintainer of the Australian HP Museum) for posting the Link to the 95LX User Manual!

This constitutes the "missing link" to LOTUS 123 documentated features & commands left out from the 200LX Users Guide.

Best regards

Peter A. Gebhardt


Nice purchase!

Well, I use Turbo Pascal 7.0 with mine. I do believe that Turbo 5.5 is still available for free from the Borland website (along with some other compilers). Set yourself up with an old computer and enjoy!

For porting, I ended up making a homebrew cable. I used the smaller end of a four pin CD-ROM to Soundcard (inside the computer) cable and wired it to a serial cable. Surely, the plans are out there somewhere. :) I never got the connectivity pack to work properly under windows. My guess is that you'll have to try some options. There is a program called DosBox that seems to work well - it might work with the connectivity pack. Unfortunately, I have have had the most luck with transferring files using Kermit (use Hyperterminal in windows).

Final thoughts: use good fresh alkaline batteries (watch the polarity carefully!!!) and a new CR2032 for the backup and it should run well.

Have fun!



Thank you all for your replies. It looks like I'll have no problem getting my hands on some good development tools!

I was also glad to hear that the manuals are available on-line, since I'm getting this machine without any of them.

One other thing that I'm not getting is a serial cable, but I've heard that the PC<->HP-48 cable is identical, and I do have one of those, so hopefully I'll have everything I need.

Thanks again!

- Thomas


I used my 48/49 cable to link up the 95LX. It should work for you.


10 and more years ago I wrote some small programs for the 95LX with MS QuickC 2.0 or MSVC 6.0. Both allowed using inline assembler, but mostly I wrote external ASM files which I assembled with MS MASM 5.1.

The latest DOS mode compiler from MS was Microsoft Visual C++ Version v1.52c for DOS and Windows 3.1x development. This CD was also included in later 32bit MS Compiler packages.

What's the difference between the use of MS compiler on one side and the Turbo / Borland products on the other side?

The 95LX has internal applications. They are started by the "System Manager". With a development kit it was possible to create own applications called by the System Manager. These tools have used the Microsoft Assembers / Compilers and Make tools. I found a small annotation that it's also possible to create such applications with the Borland compiler, but with more work.

Small excerpt from BORC2EXM.TXT :

[...] Yes, believe it or not, you can use Borland tools to create System Manager compliant applications for the 95LX! Although this has been tested only with Turbo C++ and Borland C++, it should work for the whole Turbo C family. The two basic problems to work around are the startup code and the E2M program. [...]

The HP-95LX is using a Intel 8088 CPU core, a 8086 variant with an external 8 bit data bus. For those, in short and incomplete words, who don't know the difference between the 8086 and 80186, the 80186 has the additional real mode opcodes, but not the protected mode of the 80286 CPU.

Hope this helps,



Edited: 6 Sept 2007, 2:53 a.m. after one or more responses were posted



What's the difference between the MS compiler on one side and the Turbo / Borland products on the other side?

The former is from a company once led by a megalomaniacal marketing magician who couldn't stand to be second in anything, and yet was second for years. The latter company is the one that led the maniacs from micro-land with their development tools, starting with Turbo Pascal. This company was led by a self-aggrandizing megalomaniac who was famous for expensive stunts. (Actually, his proclivity for wasteful spending helped give Silicon Valley it's reputation for such things, even though this company was over the hill in Scotts Valley.) For example, he had a 1/5th scale model made of Stonehenge in England, and then shipped the pieces to his headquarters, where it got wrongly assembled by his minions. I worked in their headquarters for a time, in the latter days when the excesses and the megalomaniac were both long gone, and they had retreated to one building on the enormous campus. The company I worked for was leasing another building. It was a very nice place, with soccer field, Olympic pool and baseball diamond, and this subtly askew Stonehenge model.

But you wanted to know about technical differences? Well, in the DOS world, Borland's compilers were very, very, very quick. The name "Turbo" was not merely a marketing flourish. But Borland and MS got into a long term fight over the developer market, and it seemed the technical lead would waver, but mostly stayed in Borland's court while DOS was king. But after Windows was released, for some reason Borland couldn't deliver the goods quickly enough, and the quality suffered. I doubt this was due to the same sort of dirty tricks Microsoft was playing on Lotus, Stac, Novell, WordPerfect and a host of others during this same time. It's more likely Borland just forgot how to create developer tools. Amnesia, I would guess.

Be that as it may, my impression is that for DOS, Borland's tools are better, despite Microsoft's valiant attempts to poison Borland's devel... * Ahem, I guess that would that would be slander, if it weren't satire. But for Windows, Visual C-- and its co-conspirators are better, if only for the fact that they've been market leaders so long, that most of the cool examples out there on the net are targeted at those tools.



Another big difference is that Borland's success began with Pascal, and they continued to support the language. They came out with an Object Oriented version that is in their Delphi products. You won't find comparable support for Pascal in Microsoft's toolbox.

Edited: 5 Sept 2007, 7:13 p.m.

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