Posted on 12/16/2005 2:15:21 PM PST by nickcarraway
My current hobby, though, is the Atari 2600. Programming for that thing is totally unlike anything else. The hardware takes care of most horizontal timings, but code must supply the vertical. There are no interrupts--just two slight concessions to make the programming possible:
-1- A store to memory address 2 will freeze the processor until the start of the next scan line.
-2- There's a countdown timer chip which can't trigger an interrupt, but which can be polled about how much time remains.
The Atari 2600 console itself includes 128 bytes of RAM and no ROM. There is 4K of address space available at the cartridge port, which most cartridges populate with 4K of ROM (a few used 2K). Some cartridges use bank-switching to allow 8K to 32K of ROM, and a few cartridges include some RAM; the latter is tricky because neither the phi2 nor R/W line is available on the cartridge connector.
Given the limited resources available, the programmer has to supply all necessary data to the display controller chip essentially in real time, and generally only do game processing during the top and bottom borders of the screen. Because there are no interrupts, nor even a hardware vertical sync counter, game processing that takes too long will cause loss of vsync.
Despite the incredible simplicity of the hardware, the 2600 manages to do many things that more technically-sophisticated competitors could not. Unlike most systems whose display properties were strictly set in hardware (e.g. sprites are a single color and 8 lines tall), the 2600's display properties are mostly set up in software. Although it's impossible to update all of the display registers every scan line, a programmer is free to choose which registers will be updated and how, and to do different parts of the screen differently. Although some systems like the Commodore 64 allow a program to change display setup mid-screen, none take it to anywhere near the level of the 2600.
BULLCRAP! I remember seeing dot matrix 17" wide green bar printouts of hot digital women in the mid 70's at my dad's shop. This was back in the days of the punch card/magnetic tape COBOL 1/2 acre mainframe stuff.
Teletype porn is even earlier than that. :-)
One of my oldest computers is a PDP-8 with and ASR-33 as its terminal. My very oldest working computer is a 1963 Minivac 6010.
The early Atari 2600 cartridges were 2K ROM, and it's possible to do a very playable game in 1K (Thomas Jentzsch's Splatform, e.g.). I think the largest single-game Atari 2600 cartridges were 32K. Since 1977, games have grown in size A MILLIONFOLD.
I have been looking to upgrade to a Commador 64 for about 15 years now.
Maybe its time to make the move.
They will have some kind of DOS, maybe with a GUI. It's going to be hard to break into the market at this stage. VIC-20 was tremendous fun and easy to work with, perhaps the new box will also be friendly to hobbyists.
I got one of the first 500 C64s back in 1982 or so.
Sold it in college, around 1986, for $25 for beer money ;)
Served me well, but those drives were HUGE and sloooooowwwww.
I have an original 1st gen Atari Pong machine sitting next to my Xbox360. Quite a contrast.
10 GIG?! Even my 486 only had 200 MB.
Have fun :-)
Gil: Now, let's talk rust-proofing. These Colecos'll rust up on ya' like that, er ... shut up, Gil. Close the deal ... close the deal!
LOL! I remember that!
LOL!
IMHO.
THE open standards of the PC made the difference.
Made Microsoft a fortune, and screwed IBM.
OMG! I started with a C64...in the area I live there were about 7-10 WONDERFUL BBS's...I LOVED doing graphics on Commodores..we had so much fun back then (late 80's early 90's) I remember when some of us went from 300 baud to 1200 we thought it was the MOST amazing feat...then to 2400!! I HATED it when pc's took over- I was a long time adjusting.
WOW...talk about memory lane. They had some fantastic games too..
Yah. Started with TI, went vic, then c64 but hardware was costing so much even a cheep computer system was costing a couple thousand a year. so made the switch to PC and haven't looked back.
Well, I DO look back. on any number of sites you can get C64 emulators and rom dumps of the programs so you can still play the old games on the PC. So when nostalgia hits too hard and I start wishing for the old days, I'll break out Raid on Bungling Bay or, *sigh* Questron. Most of the emulators don't get the Questron dungeons right though. *SCREAM*
Those were the days when you could know a computer inside, and literally, out.
*sniff*
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