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A > ATARI  > 800


Atari
800

Untitled Document

Richard Edmondson reports :
If I remember correctly, the Atari term for "sprite" technology was actually called "Player/Missile Graphics". "Sprite" was the Commodore term for similar technology two years later. P/M Graphics allowed game designers to define graphics components of the moveable icons (players) as well as lasers, bullets, etc. (the missile) and manipulate them through direct memory calls, resulting in superior speed and animation capabilities over competing systems. Not really all that different from today's object-oriented programming.

Thierry Gaerthner reports :
In my opinion, the ATARI 800 is definitely the best 8 bits home computer ever made ! OK, I can already hear a lot of protestation in the crowd :-). You're right a few other machines were cool too. But if you consider the time the ATARI 800 had been released, its features were just completely amazing !! Just think about its elegant architecture : dedicated custom chips, very nice video with DMA memory management, ANTIC as a very powerful and unique graphic chip performing things that most machines still could not do a half decade later (hardware scrolling, hardware sprite (player/missile), entirely free video memory allocation and video mode mixing with display interruption throught display list, 256 color lookup table, character and pixel video modes, ...), very correct sound effects (OK, not as good as a SID of course but really honnest and quite interresting in term of sound effects using white noises...).

OK, so I hope that most of you will agree that in term of video and sound, at that time, no other machine could outperform the ATARI 800 ! But another pretty strong feature that we forgoet to mention too often was its Operating System (or BIOS if you prefer) ! Not some kind of BASIC ROM' sub routines. No, you had a very neat and structured Operating System ! A generic I/O system with in mind the addition of extra peripheral to be simple and available from any application, a real boot sequence (you never had to type on the keyboard such awfull things as LOAD"*",8,1,"PACMAN.BAS" ;-), all the games were 100% language machine, not a single byte of BASIC :-) !

The last feature I'd mention is the joystick ports : the fact they were based on a 6810 PIA made them fully programmable as Input or Output, pin per pin ! Yes, that's true I printed all my documents on a standard Centronics printer using a special cable and the associated driver I designed by myself ;-).
At that time, the ATARI 800 was just my dream machine, but also the one I could never afford because when it had been released in France in the early eighties, it's price (for the single computer, no floppy disk, no monitor !) was around 1300 Euros ! Hopefully, a few years later, the ATARI 800 XL was released at a much more affordable price ! We maried and even if had no babies, we lived happy ever after :-).

Tristan Smith reports:
The Atari computers had some really amazing things built into them. It didn't support "Sprites", but had Player/Missle graphics, like Richard said. The P/MG was much more powerful and was easily set up.

One amazing feature the ATARI had was VBI or Vertical Blank Interrupt programming. You could write a short program that would run when the screen was between refreshes. The game "Eastern Front 1941" used this to determine its moves so it didn't slow down what you were doing.

Another neat thing the Atari's had was how devices were set up. There was a table of device letters and pointers used any time a device was called, such as S: (Screen), E: (Editor) and so on that controlled all high level access. Well, this table was in RAM and it was read backwards! What this means is that if you wrote your own device replacement, you just added it to the stack and yours was used first.

The ATARI had a bunch of chips in it that handled alot of the work so the CPU could actually do the work. The most important was ANTIC. Like the VBI, you could write a quick program which would run when the electron gun was in between line sweeps. It had to be very short, but it did allow you to do things like, changing the color of a line or animating fonts. Yes, the ATARI did allow you to easily change fonts. Using the VBI you could actually animate the fonts.

One interesting thing about the VBI, ANTIC, and stuff was that the changes you made to point to custom code kept going until you turned them off. You could be programming in BASIC with a status line at the top of the page in a different font and color. ANTIC was limited to single line changes. In other words, you could make a line as color or mono, text or graphics, but not a combo.

Another thing the ATARI had, but was rarely used was color artifacting. It was a strange "quirk" with the computers. What happened was that, in color modes, if you placed the pixels just right it would make other, unplanned colors. It was possible to get a huge number of colors on the screen at the same time, but it was difficult to control. ANTIC magazine (anyone remember that) had a program you could use to set the colors correctly and get thousands of colors on the screen at the same time.

One problem the 400/800 had was math speed. It was not due to the processor, but the OS code. When the XLs came out, a large number of BASIC programs had timing issues. The BASIC command X=10^5 or any advanced math function were often used in delay loops. The math was MUCH faster in the XLs.





 
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