46 votes
Accepted

How did Atari lose money on home computers?

In 1982 the original 400 and 800 were on the market. These were expensive machines to implement. Even the low-cost 400 was significantly more complex and expensive than something like a VIC-20. Here ...
Maury Markowitz's user avatar
36 votes
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What does "jmp *" mean in 6502 assembly?

MADS uses * in three ways (See MADS "Manual") Using the current assembly address for calculation of an address, i.e. the one the actual statement is assembled to. Multiplying in expressions. Mark the ...
Raffzahn's user avatar
  • 219k
34 votes
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How did "Ballblazer" pull off fast, smooth, first-person, solid-model 3D on Atari 8-bits?

There are two elements: The background The sprites The background is very straightforward: The vanishing point never changes so you have one graphic with a checkerboard in perspective. That graphic ...
Thomas's user avatar
  • 3,822
32 votes
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Why did the Atari 800 designers choose such a radical system design?

The physical design of the Atari 800 was radical, but not for reasons related to the aspects you highlight. As others have commented, using multiple boards for a system was pretty standard at the ...
Stephen Kitt's user avatar
29 votes

How did Atari lose money on home computers?

I can only add to the other answers with observations and memories, some of which come from owning an Atari 800 in the time period you're asking about. First, notice the names flying around in the ...
Jim Nelson's user avatar
  • 3,773
27 votes

How did "Ballblazer" pull off fast, smooth, first-person, solid-model 3D on Atari 8-bits?

The gameplay can be implemented without any 3D calculations (or very little, depending on your definition of 3D calculations): The checkerboard never rotates, so it can be drawn using affine segments ...
Stephen Kitt's user avatar
24 votes
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The almost-was Atari IBM PC

We can no longer ask Bill Lowe, may he rest in peace. But here's a little more information: According to Blue Magic by James Chposky and Ted Leonsis, when Entry Level Systems Lab Director Bill Lowe ...
snips-n-snails's user avatar
23 votes
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Does every retrocomputer and console with NTSC composite output have 'artifact color' ability?

In composite video, a scanline has the following format: Every line has: a sync mark, which is the lower level, on the left. a color burst, which I'll explain below. video data. The sync mark is ...
Thomas's user avatar
  • 3,822
21 votes
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Troubleshooting and reparing an Atari 800XL with a single key not working

In the end, I decided that it had to be easier to take the keyboard apart than to de-solder the 4051's and so I carefully removed the 18 tiny screws from the back of the keyboard. It wasn't nearly as ...
Geo...'s user avatar
  • 10.2k
20 votes
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6510 clock rate of C64: Why was it considerably slower than the 6502 of the Atari 800?

Somewhat of a guess:  The C64 always interleaved CPU and graphics RAM access (with additional graphics cycles if necessary), effectively accessing RAM at 2 MHz. Judging from the ANTIC Timing ...
dirkt's user avatar
  • 27k
19 votes
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What did the cassette bootloader in 8 Bit Ataris do?

De Re Atari describes the cassette boot protocol, which helps understand why bootloaders were (nearly) always used. In cassette boot mode, the operating system reads a record from the tape recorder ...
Stephen Kitt's user avatar
19 votes
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Atari 800 CPU - 6502 vs. Sally

It seems the 6502C "Sally" added a HALT pin to allow Atari to remove four support chips and thereby build cost-reduced versions of the Atari 400 and 800.
snips-n-snails's user avatar
18 votes
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Why does this 6502 code push a function address onto the stack before calling?

That's a usual way to an indirect JSR with a 6502. The 6502 does not support indirect subroutine calls (*1), so it has to be done in software. Indirect subroutine calls are a useful tool for function ...
Raffzahn's user avatar
  • 219k
17 votes
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Why did the Ataris have such clear displays?

Why did the Atari's have such clear displays? I suspect it might have something to do with all the shielding No. As usual it's about the effort the designers did put into the display. To reduce cost,...
Raffzahn's user avatar
  • 219k
16 votes

6510 clock rate of C64: Why was it considerably slower than the 6502 of the Atari 800?

Memory chips of the era were limited to an access speed of about 2MHz. On the Atari 400/800, cycles could be given arbitrarily to either the processor or the display hardware. On the Apple II and ...
supercat's user avatar
  • 35.7k
16 votes
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Why did the Atari 800 have a flying RF lead?

The internals of the Atari 800 were enclosed in an earthed aluminium chassis that screened the internal electronics and reduced the radiated electro-magnetic interference (EMI) it produced. Radiated ...
TonyM's user avatar
  • 3,658
15 votes
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Was the Atari 400/800 internal speaker of any use besides key click?

The speaker was known as the console speaker and is controlled using the byte at location 53279; as indicated in Mapping the Atari: POKEing any number from zero to eight will cause a click ...
Stephen Kitt's user avatar
15 votes
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Why did the Atari 5200 forsake compatibility with 400/800 game cartridges?

At that point in time, Atari had separate divisions for the Home Computer market and the Consumer Electronics, or console, market. There was a lot of competition between the divisions. The Consumer ...
Troff's user avatar
  • 476
14 votes
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What were the selling points of the Atari 800 over the 400?

There are a few improvements that made the 800 more valuable Candy Coleen (400) (800) RAM (original design 1979) 4 KiB 8 KiB RAM (...
Raffzahn's user avatar
  • 219k
14 votes

What does "jmp *" mean in 6502 assembly?

I suspect the * means the current instruction/location, as it does in some other assemblers, like PDP-8.  Often it would be used in an expression like *-label in the data section to get something'...
Erik Eidt's user avatar
  • 3,347
13 votes

Does every retrocomputer and console with NTSC composite output have 'artifact color' ability?

Colour in NTSC is represented as the high-frequency part of the signal. A colour-aware TV will separate the low and high frequency parts. The colour decided will depend on the relative phase of the ...
Tommy's user avatar
  • 36.5k
11 votes
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Can Extra Joystick Ports be Added to the Atari XL/XE Series of Computers?

No. At least not in a software compatible manner. The PIA which is used in the 800 to read joystick ports 3 and 4 was repurposed in the XL systems to control memory mapping (eg. disable OS ROM, ...
Tim Locke's user avatar
  • 4,801
11 votes

What graphics sytems used display lists?

The Super Nintendo Entertainment System (called Super Famicom in Asia) is mostly TMS9918-like. However, the CPU's integrated memory controller has its own counterpart to Amiga COPPER, called HDMA (...
Damian Yerrick's user avatar
10 votes
Accepted

Will the Atari 800 work without any expansion cards installed?

I just booted mine with the three 16KB RAM packs removed. At power up it displayed a green screen. With a Centipede cartridge, the 10K ROM pack, and no RAM packs, it just displayed two medium grey, ...
Tim Locke's user avatar
  • 4,801
10 votes
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Do any Atari 8-bit emulators produce the disk / tape I/O sound?

I use Altirra, which does emulate the drive beeping. http://www.virtualdub.org/altirra.html Note: I had to tweak the preferences to get the drive beeping turned on, and it was some time ago, so I ...
Geo...'s user avatar
  • 10.2k
10 votes

How did Atari lose money on home computers?

I'm going to make a guess. For starters, Maury makes a good point about the manufacturing cost of the 400/800 series. I certainly think that is a key point, but not the whole story. Based on data ...
bjb's user avatar
  • 16k
9 votes

6510 clock rate of C64: Why was it considerably slower than the 6502 of the Atari 800?

It's mainly based on VICII's (or generally for memory mapped video adapters) demand together with limitations on access time for RAM and ROM components. VICII has to access the RAM (video character, ...
Johann Klasek's user avatar
9 votes

Does every retrocomputer and console with NTSC composite output have 'artifact color' ability?

Let's sort out some different kind of color artifacts. 1) The composite signal carries both lumincance and chrominance, the latter encoded in the phase of the color carrier. That means if it's ...
dirkt's user avatar
  • 27k
9 votes

Troubleshooting and reparing an Atari 800XL with a single key not working

I've found that the old Atari keyboards can lose conductivity and that pressing they key repeatedly, not necessarily with a lot of pressure, can revive them. I've had Apple II keys start working again ...
Tim Locke's user avatar
  • 4,801
9 votes

The almost-was Atari IBM PC

First off, the website stating IBM execs were placed in carts and allegedly turned-off by Atari's culture is flat out wrong. That happened with Sears executives and Atari's management tried to hide a ...
Jeremy Holloway's user avatar

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