Atari vs Commodore which one was stupider.

[InTheSand]

Hyperspeed wrote:
What is meant by 'Chunky Pixel' anyway, I read it was a 1:1 pixel but then NTSC 640x480 is 1:1 (with overscan)?

Assuming a 256-colour display, chunky screenmodes are those where one pixel on the screen can be written in a single go using one byte of data.

In contrast, the Amiga's AGA display in a 256-colour mode would require 8 separate writes of one bit each, to each of the eight bitplanes that make up the final display.

Taking a simple monochrome screen, one byte would equate to a horizontal line of 8 pixels, where the pattern of the line equates to the binary pattern of the value written to it (where 1s correspond to a dot, and 0s to a blank). E.g. a solid line would require a value of 255 (FF hex) to be written as this equates to 11111111 in binary, and a blank line would require 0 to be written as this equates to 00000000 in binary, with a stippled effect being obtained by writing alternate 0s and 1s as in 01010101 (byte value of 85 (55 hex)). The Amiga's native screenmodes are effectively made up of multiple monochrome-style "planes" of graphics, which are then layered together by the chipset.

The Akiko chip simplified the writing to all of these bitplanes and effectively gave the developer a chunky display to work with, where one byte written to change a single pixel would be split across the eight bitplanes via hardware, thereby speeding up screen updates vs doing the same operation in software.

I'm sure someone can explain that better than I've just attempted!

 - Ali

[Hyperspeed]

Actually InTheSand that was very good.

The term 'chunky' really is a bit misleading isn't it... and since the PC always used this method why did the Amiga deviate from this?

If I visualise your description I get the display being made up a bit like placing consecutive bits of grease-proof paper over each other, each with something written on it.

I suppose every cloud has a silver lining and maybe the planar system of the Amiga had benefits...

What were they?

:-D

[Lando]

Hyperspeed wrote:

I suppose every cloud has a silver lining and maybe the planar system of the Amiga had benefits...

What were they?

:-D

For one thing, scrolling - you could scroll the entire display just by writing to the Bitplane Pointer registers.

On the Amiga, what is on the screen can be anywhere in Chip RAM, while a VGA PC always displayed whatever data was at a0000000h, you had to write every damn byte again (move 64000 bytes of data to scroll one line).

Even at 32 bits per mov instruction that's 16000 operations to scroll a single line, while on Amiga, it was 2 instructions per bitplane (each bitplane has two address registers bplxpth, bplxptl).

[Hyperspeed]

What other machines used planar systems?

I bet the Megadrive/Genesis did, you couldn't get smoother scrolling than Sonic The Hedgehog games.

Also, HAM modes, how would you explain this technology - I raise this since both the Amiga and Atari Jaguar could do them.

Alien Vs Predator on Jaguar was a fps that actually played in HAM mode!

[bloodline]

Hyperspeed wrote:
What other machines used planar systems?

I think most machines actually had both modes...

I bet the Megadrive/Genesis did, you couldn't get smoother scrolling than Sonic The Hedgehog games.

Also, HAM modes, how would you explain this technology - I raise this since both the Amiga and Atari Jaguar could do them.

HAM mode is basicly a 16 colour mode, that uses 6 bits instead of 4. The two extra bits are used to tell the hardware hold the data from the pixel to the left of the current pixel, and then use the four pixels of the current pixel to adjust (modify)  either the red, bue or green component.

The pixel data was assigned as such:

00 xxxx : use color from palette index xxxx;
01 gggg : keep red and blue components from previous pixel, use gggg as green component;
10 rrrr : keep green and blue components from previous pixel, use rrrr as red component;
11 bbbb : keep red and green components from previous pixel, use bbbb as blue component.

By carefully selecting the 16 colours, and making sure that the colours are smoothly transitioning  (i.e. like in photos) then you can get very realistic images!

HAM is basicly a form of image Compression, where 12bits are compressed into 6bits.

Alien Vs Predator on Jaguar was a fps that actually played in HAM mode!

Somewhat pointless by the time the Jag was released... just add more  memory.

[Psy]

uncharted wrote:

But the Amiga had the advantage that it was seen by parents as a computer and not as a toy.  Many of my friends got one "to do their homework" ;-)

Also, it's debatable how much the Megadrive ate into Amiga's sales, as Amiga sales still increased year on year after the introduction of the Megadrive.

yet Sega didn't have a problem with R&D (it had problem with infighting between Sega of Japan and Sega of America and general managment getting in the way). If Sega wanted to re-entre the computer market (it had a Z-80 computer back in the early 80's) back then it defenitaly had a strong enough R&D to come up with a Amiga killer, problem was Sega never really had to think of compitiblity much and it's hardware as all over the place: they used Z80, 68000, NEC V60 and v70, Intel i960-KB, Hitachi SH-2 and SH-4, Intel Pentium 3 & 4 (probably forgetting a CPU or two) and too many chipsets to list.  On the plus side if Sega did make a computer back then they would alway have had something in the pipe from the Arcade R&D even if it mostly likely would be totaly incompatible.

[darksun9210]

but then did Sega want to do an 'Amiga Killer'?

its my limited understanding that Sega used Amigas for Genesis/megadrive development work.

The Sega dev kit being a hardware dongle that plugged into the sideport of the A500, and allowed programming of cartridge eproms, and running stuff.

quite if it allowed you to run say, sonic the hedgehog on an A500 i wouldn't know... ;-)

[Psy]

darksun9210 wrote:
but then did Sega want to do an 'Amiga Killer'?

its my limited understanding that Sega used Amigas for Genesis/megadrive development work.

The Sega dev kit being a hardware dongle that plugged into the sideport of the A500, and allowed programming of cartridge eproms, and running stuff.

quite if it allowed you to run say, sonic the hedgehog on an A500 i wouldn't know... ;-)

Yhea for the Genesis, by the time Sega was looking at the Hitachi SH-2 and 3D, the Amiga was no longer powerful enough for devlopment.

The AAA would have made the Amiga a 2D powerhouse, but even if it came out Sega would have had no use for it when they went 3D.

If Sega came out with a computer version of the Saturn it probably would have sold better then the Saturn, as Sega could have brought built in 3D cheap to computer users.  Where was Commodore in 3D technology? As far as I know Commodore had nothing even on paper to give the Amiga 3D and back in 1995 built in 3D (at par with the Playstation and Saturn) would have been a huge selling point since neither Macs or PCs had it.

[bloodline]

Psy wrote:

If Sega came out with a computer version of the Saturn it probably would have sold better then the Saturn, as Sega could have brought built in 3D cheap to computer users.  Where was Commodore in 3D technology? As far as I know Commodore had nothing even on paper to give the Amiga 3D and back in 1995 built in 3D (at par with the Playstation and Saturn) would have been a huge selling point since neither Macs or PCs had it.

The Nyx had features to help 3D work... the AAA might have had some blitter modes to assist texture mapping (I seem to recall reading such).

[Hyperspeed]

Psy: When/what did Sega use Pentium chips for?

I think if AAA had any 3D capability it would have been similar to the 3DO.

It was things like Virtua Racing and Starwing that got polygon processing into the mainstream, I think everyone had been sleeping up until that point.

Both Commodore and Atari made some peculiar decisions in terms of upgrade progression though... look at the A500/A500+/A600 and the Lynx I/Lynx II.

[Psy]

Hyperspeed wrote:
Psy: When/what did Sega use Pentium chips for?

Very recently for the arcades Lindbergh
Here is a news article

Sega's R&D is not what is use to be so they no longer use exotic and custom componets but it looks like the Lindbergh still gives Sega devlopers lots of power.

It was things like Virtua Racing and Starwing that got polygon processing into the mainstream, I think everyone had been sleeping up until that point.

Virtual Racing was released in 1992 and Commodore went under in 1994 you would think they would have had something on paper give the Amiga real 3D capabilities.

[Hyperspeed]

Where can you buy The Deathbed Vigil on DVD/VCD?

Is it just pot luck on eBay?

[Nitro]

@ Hyperspeed
http://www.frogpondmedia.com/dbv/sales.html

[Hyperspeed]

Wow, thanks Nitro!

I've just ordered the Euro PAL DVD with postage for 40 USD.

PayPal said D.Haynie will appear on my bank statement...

That's a bit like Jesus appearing on peoples' toast!

:-D

[Nitro]

@Hyperspeed
I waiting for the day, when someone has An A2000 on ebay with with an acid leak around the battery and you can clearly see daves face on the board. :-)

[Hyperspeed]

:-D

Speaking of ghostly images, didn't Andy Warhol paint Debbie Harry on Deluxe Paint or something when the A1000 was released?

Was there any file or painting made public of this?