Interview with Christophe Kohler

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Interview with Christophe Kohler, the developer of PSPVice (C64 Emulator for Sony PSP).

Introduction[edit | edit source]

The Interview with Christophe Kohler, the developer of "PSPVice", was created from SCACOM-Team. The article was in English-SCACOM issue 1 (December 2007). The interview was done by Stefan Egger.

Interview[edit | edit source]

Hi Christophe! Tell the readers and myself a little about you.

Hi. I’m 34 and I’m an independent professional game developer (Website I’m married, no child and we live near Paris (South west of Paris, near Versailles). I’m a former Amiga demo-maker (in the 90’s). I’ve always been into the demo scene and amateur game scene. Now, I’m helping the younger generation through internet forums (moderating a forum about game creation on a famous French game-website)

For what systems have you developed

I’ve worked on PS2, PSP, DS and soon Wii surely in both amateur and professional way.

What programs have you developed?

Here are the amateur programs I’ve created:

On PSP: I’ve work on a C64 emulator. I’ve used VICE sourcecode and create PSPVice. Recently I’ve also created the VIC20 and PLUS4 versions.

On PC: I’ve recently created a FPS (First Person Shooter) for blind people. That may sound strange but it’s playable! Download here

On PS2: I’m working on a new VICE version for PS2 (someone asked me for and I like the idea).

And many more small programs (remember I’m “old”)

We want to talk about the Commodore Computers! What classic computers do you own today?

I have 2 C64 and a C64-C (with tape, 1541 and 1541-II drives). I also have an Amiga 1200 with a 1084 monitor.

What is your favorite computer?

C64 was my first computer so it has a special place in my heart, but my favorite computer is Amiga because I spent so much time programming and playing on it.

What was your first Computer?

My first computer was a C64 with datatape and green monitor (very hard to play the piranha sequence in “Aztec challenge”). My first games were “Blue Max”, “Tapper”, “Up and Down” and “Spy Hunter”.

C64 was not very popular in France at that time. “Amstrad CPC” was the leading computer. When I saw the C64 at a friends place, I knew I wanted one. Few stores were selling it, and I remember that my mother and I searched for a long time to find one. Thanks to her, that was the right choice.

What computers followed after the C64?

Next, I bought an Atari ST. I kept it until I saw “Hybris” on Amiga at a friend’s place, then I bought an Amiga 500. Later I bought a 1200.

What’s the hardest part of emulator-development?

The emulator core was made by the VICE team. They did a great job. I did the port on to PSP. The most difficult part is the speed of emulator. Even if C64 is a “small” computer, an emulator is a complex piece of software and the PSP is limited to 333 MHz. So it’s difficult to create an emulator where a lot of games run at a good speed. Fortunately most of the C64 games run smoothly on PSP.

Why did you purchase a PSP? What firmware and accessories do you have?

I bought the very first PSP model (1.0, Japan version). When I first saw the PSP, I fell in love with its big and clear screen. I do not have any accessories apart of the 1GB memory stick.

How often do you use your PSP?

At the moment I use it not very often. The PSP games are not very interesting for me. I’m manly using my PSP to play with PSPVice and some others emulators (SNES for example).

What’s your list of favorite homebrew games and releases for the PSP?

  • Snes emulator is excellent. (snes9xTYL).
  • I’m also using “BookR” to read PDFs.
  • ScummVm and MAME are also nice on PSP.

Why did you develop PSPVice?

I mainly wanted to play my favorites C64 games on PSP and there weren’t any emulators at that time. That’s the reason why I’ve created one.

Is it important to get feedback from from myself and other users?

The first version of PSPVice has been done for myself (quite selfish isn’t’ it? ;) ), so I did not need any feedback at that time. After some people started writing to me and sending congratulation messages (that was nice) and asking for some new features. We all use and play different games, and we all have specific needs. From the request I received PSPVice is now improved (directory browsing, nice stereo sound).

There is another emulator called C64 PSP too. How would you rate this software?

C64PSP is a nice and fast emulator. I’ve contacted its author when I started coding PSPVice (we started at the same time). He is a nice guy. It’s good to have several emulators available. This way, players have choice and more chances to be able to play their favorite games (due to speed and compatibility problems).

What can you say about the VIC20 Emulator for PSP? Tell our readers some secrets about it?

The secret is that I do not know anything about the VIC20 and the Plus4 (shame on me). The development was quite quick (one day for each, for the basic version). I’ve did it because some people asked me for this versions, but I don’t use them myself.

How long did development and porting the PSPvice and VC20-PSP take?

I created PSPVice in 2 or 3 weeks (in my spare time). I’ve used the work I did on PS2Vice (with authorization from the author) so it helped me a lot. The work was: Compiled VICE core sources, Compiled PS2VICE and modified for the PSP. Then I added the new PSP features. The first version was completed at the end of 2005. The new PSPVice features (1.1) took me one week.

What are the new functions in the next PSPvice?

The major update is the possibility to browse any directory. Lots of people use a large amount of C64 games so the old system was a problem for them. The “stereo” sound effect is a nice feature. A friend of mine taught me that trick for my first DS game (decay two mono left/right sounds to have a small stereo effect). The result on PSPVice is very nice, I like it a lot. I updated the VICE core. PSPVice now uses the latest sources (1.22 version of august 2007). The other features are things people asked me for:

  • Autofire
  • P00 support
  • Explain how to save a disk
  • Display a keyboard with “shifted” keys
  • Hide icons in PSP browser
  • Welcome text
  • New menu organization
  • Other small fixes and updates

What other features do you have planned?

PSPVice is now mature and allows players to play lot of C64 games. I’ll wait for feedback and requests. If I like the request, I’ll maybe add them in PSPVice.

Do you have a homepage in internet? What the address and content?

You can see my page about C64 and Amiga. The other information is about sports and my resume.

What you will say to the readers?

I had and still have a lot of fun with Commodore computers. As I said, they have a special place in my heart and I’m glad to see that a lot of people are sharing that feeling. Here is a photo of the shells next to my desk. As you can see C64 stuff is not very far away.

Thanks for Talking to us.

Thanks for your interest in PSPVice.


Links[edit | edit source]

Autor[edit | edit source]

Interview Nr. 1; (C) Stefan Egger from SCACOM English issue 1 (Dezember 2007)