Friday, June 20, 2025

ALL ATARI ST GAMES

https://www.youtube.com/watch?v=aUHtpNFZV38

@john2001plus
0 seconds ago
I wrote a videogame for the ST and the Timex Sinclair 2068 called Diamond Mike. The ST version was published by XLent Software in 1986. I saw it on store shelves. (There are videos of it on YouTube.) I am not aware of a downloadable version, but I have a physical copy. 

I am surprised at how good some of these games look. The original ST only had 16 colors from a palette of 512.

Sunday, June 15, 2025

NES Games Were Written in Assembly

https://www.youtube.com/shorts/kFjSxwijItU

@john2001plus
0 seconds ago
I wrote games in Assembly for the SNES, Gameboy Color, Atari ST, and Timex Sinclair 2068.

Wednesday, May 21, 2025

Defender (Atari 800 | Atari 5200) - Chronologically Gaming



@john2001plus
1 day ago 
My experience watching the home versions of Defender might differ from actually playing them, but just watching the game makes me uncomfortable. First, the music is monotonous—especially since you die so frequently, you keep hearing the same repetitive sound over and over.

My second issue is with the apparent choppiness of the game and its lower resolution compared to the arcade version. Visually, it seems like a much worse experience, although it might still be fun to play. At least twice, it looked like you didn't get hit but died anyway—possibly due to the choppy animation.

I have to admit, it is a great arcade conversion.

From what I've read, the Williams arcade version didn't use hardware sprites to save on costs. As a result, the processor had to work overtime to animate the graphics. The arcade machine used two processors: one for graphics and the other for sound. I believe the scrolling was also handled in software.

The arcade version used a 320x256, 16-color display, which could require up to 41KB of screen data. Considering that a single 6809 processor was responsible for handling all the graphics, that's impressive—though still within the realm of possibility.

BTW, 16 color graphics use 4 bits per pixel. On the Atari ST, this involved 4 parallel bit planes, which was a nightmare to write graphics code for, which I did back in 1986.   However, if the video memory were arranged as two 4-bit pixels per byte, then that would be ideal.  It would be much easier to code for.  (I think I heard that the Apple II GS did this.) If it were me, I would only move objects in increments of two pixels horizontally, which makes the code much simpler, and the user is not likely to notice the difference.


@john2001plus
1 day ago 
I found another source that said that the Defender arcade had 38K of video RAM, two pixels per byte, and only a 1 Mhz 6809.  It lists the graphics resolution as 292x240, which is slightly less than what I posted above.  This may have been deliberate to allow for overscan, as the monitor is designed for 320x256.



@chronologicallygaming
7 hours ago
That's a great analysis of the differences between the arcade and home versions of Defender! I always felt like the home version was a good compromise. Thanks for the comment!


@john2001plus
7 hours ago 
 I agree it is a good compromise.  As I said,  watching and playing might be different, so I will attempt to play the home version through emulation.

I have the Arcade1up version of Defender.  Having to hit a button to reverse direction feels like too many buttons to deal with.

Thursday, May 15, 2025

Who was the first video game boss? (And why do we call them that?)


The video points out that having a more powerful enemy at the end of a level started with a Dungeon Crawler in 1974.

Tuesday, April 1, 2025

Magnetic Core Memory

512 byes of RAM costing $2,000:

https://www.youtube.com/shorts/mrBz9-9qgGw

One of the biggest limiting factors of early computers was the cost of RAM.  In the late 1970s, I remember seeing an advertisement for 64K of RAM costing $1,000.  Today, you can get 64 gigs of DDR4 for under $100.

This is why the Atari 2600 video game system released in 1977 only had 128 bytes of RAM.  

The first TRS-80 came with 4K.  The VIC-20 had 5K.

The Sinclair ZX-81 came with 1K.  Its American counterpart came with 2K.  Both were expandable to 16K.

The Nintendo Entertainment System, first released in Japan in 1983, had 4.25K RAM.

By late 1983, RAM had gotten cheaper, so we saw the Commodore 64 released with 64K, and the Timex Sinclair 2068 with 48K RAM.

The REAL TechDweeb

This is most likley an April fools joke, but maybe the real joke is that it is true.

ROC'N ROPE | Atari 2600 Game from Publisher Coleco

https://www.youtube.com/shorts/-KjotKP8bF4