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kskunk

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kskunk last won the day on January 5 2012

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About kskunk

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    Atari Mecca Sunnyvale, CA
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    Making hardware and software for Atari 8-bits and Jaguars
  1. kskunk

    Jaguar 2

    That's true and a source of confusion, but I'm pretty sure this code is for the "second" Jaguar II. Midsummer - the new chipset - was also called Jaguar II by Atari engineering during its development. (I guess they recycled the name.) In Eric Smith's weekly status reports from 1995, he consistently uses "Jaguar II" when describing his modifications to sample code to support Midsummer features. This code could be related to that effort. If you match up the code in question to the Midsummer datasheet, you'll find it's an exact match: /* if running on Jaguar II prototype, fix up DSP access */ buts = (*(volatile long *)0xf02114) & 0x0000f000; /* get GPU version */ if (buts == 3) { /* if version 3 */ *(volatile short *)0xf00056 = 0x0060; /* mess with TEST1 register */ } The above code detects Oberon, then configures it to talk to Jerry instead of Puck. This matches with another piece of history: In Midsummer, 0xf02114/GPU_CTRL bits 12-15 are documented as follows: 1 Pre-production test silicon (Jaguar One) 2 First production release (Jaguar One) 3 Pre-production test silicon (Midsummer) In Midsummer, setting 0xf00056/TEST1 to 0x60 does the following: 0x20 enable the Jaguar One Jerry interface 0x40 delay the DRAM write strobes by one half clock cycle - KS
  2. The actual slowdown is so brief it's negligible. To stay at 1.19MHz, you'd need to access RIOT on every cycle. In practice, a single RIOT access costs just 0.5 cycles and reads both joysticks at once. Controller logic is usually hundreds to thousands of cycles. (And involves TIA too.) So, bypassing RIOT could not even save 0.1% in a typical game. Hope that helps!
  3. In the 80s, me and my friends (bored schoolkids) learned how to "hack" Atari 800 games. Graphics and text are easy to find and edit on disk. Later on, one of us got an EPROM burner and within weeks we had moved into NES cartridge hacking. The burner could read the ROMs into a file on disk, where we would edit the text and graphics, then burn our changes. It was the same process we had mastered on the Atari 800. It was very impressive to other schoolkids that we made "our own Nintendo game" with our names on the title screen and crappy amateur graphics. Nevermind that the program and levels were identical - we never understood or modified the code! A more devoted/experienced programmer could go further and modify the 6502 code of an existing game - gradually turning it into something different. But starting from scratch is unlikely. Anyway, it wasn't that expensive, at least not by 1990. And I doubt we were the only ones to do it. All you need is lots of free time while you wait for the UV lamp to finish.
  4. Yes, I used a LogicPort analyzer with 2ns resolution to design the Skunkboard. I tested all the memory controller settings to make sure there was plenty of margin for my 16-bit bus trick.
  5. The access time in this mode is too short for early-90s bulk mask ROM, so it would not work. (No problem for 21st century Skunkboards, of course.) I tested it. It does not work. The buffers inside the Jaguar are too slow.
  6. I don't think I can adequately summarize all the hardware differences - their designs are so different, apples and oranges. But, there's not a huge difference between the ROM speeds when it comes to graphics performance. The Jaguar total ROM bandwidth is 10.6MB/sec (32-bit ROM at 2.66MHz/376ns) Neo Geo graphics come mostly from sprite ROM at 12MB/sec (2x16-bit C ROMs at 3MHz/333ns) Neo Geo can use 100% of its 12MB/s sprite bandwidth, but the Jaguar can obliterate that with a portion of its giant RAM bandwidth (100MB/sec). And that's what Jaguar games do - 2MB is a ton of RAM when your biggest cart is 4MB. It's not like every level uses every background and every character simultaneously - they use a fraction, and the RAM is a fine cache for that. Nor is the Jaguar that slow at 2D. The Neo Geo has a slight edge when every single sprite is scaled (1536 pixels/line vs ~1200 w/OP overhead), but the Jaguar can keep up with the Neo Geo's typical mix of scaled, unscaled, and fix (overlay) graphics. The Jaguar's 68K is crippled compared to the Neo Geo's, so CPU utilization would be a sore spot (as always), necessitating something like Minter's GPU Object List Builder to keep everything moving at 60Hz. My opinion is that the Jaguar is harder to program, but could offer comparable 2D performance. Neo Geo was making expensive games - with expensive ROMs and expensive art. Atari was making everything the cheapest they could. That probably explains more of the difference than any single technical factor like ROM speed or bugs. The USB ports are like a 6x CD - 0.9MB/sec. I wrote a USB-stick-reading benchmark for Tursi, who released it to the world. I sat back with fantasies of (other people) turning the Jaguar into a 64-bit computer with USB peripherals. But, it turns out programming USB is a lot of work. I left all that difficult programming work for other people - so far, no takers. (Seems fitting for the Jaguar...) - KS
  7. The ROM is addressed like RAM. But it would be terrible for performance to leave it in ROM - built-in RAM is up to 10x faster. Nearly every game copies to RAM first. Since the Jaguar's biggest ROM was 4MB back then, copying select assets into 2MB was no problem. Compression was often used. You can look at the memory map online to see why. The Jaguar has 24-bit addresses (like the 68K). They first split the space in half - a fast half, for RAM, and a slow half, for ROM and peripherals. They carved out 2MB of the slow half for peripherals, the boot ROM, JagCD (and its boot ROM), etc. That leaves 6MB of slow ROM - the limit of the cartridge. Of course, the Jaguar could bank switch for bigger ROMs, like any other system (even the NeoGeo did). If the Jaguar had lasted long enough for 8MB ROMs to be cheap, it probably would have had some. - KS
  8. It varies on a game-by-game basis, so there is no one answer. "Atari" (as a copyright owner) is not dead. If you want to buy a legal copy of Star Raiders right now, here you go: http://atari.com/buy-games/arcade/ataris-greatest-hits Generally, the programmers won't get anything. Even in Atari's early days, they didn't pay royalties to programmers. (That policy famously led to the founding of Activision!) Later, Atari gave bonuses to employees who wrote successful games, so they wouldn't quit. But once they quit/were fired, they get nothing. There are exceptions: Some games you remember as "Atari" games were written by 3rd parties, and sometimes those parties get the profits. In other cases, one of the many Ataris over the years sold off the rights, and now some other company owns it. At least in the US, all games are still under copyright and all of them have rightful owners. So to be legal, toys with built-in games must sign a license deal with Atari (or others), and by license, Atari gets part of the profits. With 40 year old games, the owners sometimes don't know/don't enforce their rights. A few toy makers take advantage of that and just steal the games. I've bought at least one toy with pirate ROMs in it. In that case, some Chinese company got the profits. - KS
  9. My family had a 1027 that lasted from about 1985 to 1993. We used it for the same reason as other people in the thread - the high school had stupid rules against handing in homework that 'looks like it came out of a computer'. The printer required no maintenance other than new ink, though I doubt we printed more than 1000 pages over its lifetime. It finally got boxed up and put in a barn where a few hot summers ruined it. It was definitely my favorite printer for a while. It had a great output quality to price ratio - we couldn't have afforded anything with better output back then.
  10. What a fun project! I design toy electronics for a living, so my professional instincts go straight to the bottom line: With a $49 MSRP, $10 is the absolute max you can spend on the electronics. (Unless you don't want a shell, joystick, box, manual, retailer margins, company profit, marketing, etc.) The screen is going to eat nearly half of the $10, assuming you want a backlit color LCD about the size of an old Mini Arcade. (At that price, it won't be anything like tablet quality.) With ~$5 left, it's incredibly tight. Unless you're expecting really good volumes (>1M units), you probably can't afford the software engineering to target a small CPU or tiny OS. Unfortunately, Android + MAME probably won't fit in this price range, either. (But it's very close - it might be possible this year.) For power, Alkaline cells are the cheapest option - with low-power components and a backlight suitable for indoor use, four AA batteries could last 16 hours of play time. Lots of kids will lose interest before then. (Sadly.) Including a power brick is the most expensive option, so lots of toys just include a USB cable or jack. Every home has USB power somewhere. Rechargeable batteries aren't free, but $1 could get you 1 hour of life from a rechargeable battery + USB charging system. (Again relying on the customer to supply their own USB power.) Anyway, if I were asked to develop a toy like this, I would go straight to a low-cost handheld game manufacturer in China. Look no further than Alibaba - you'll find several manufacturers who build emulator-based handheld color LCD gaming systems that wholesale for ~$15. At these prices there's not much margin for engineering, so I'd find an existing design and wrap it up in new plastics, then customize the software as much as the budget allowed. Good luck and keep us posted as things progress! - KS
  11. It's a shame they didn't transfer the ST business to a private German company like C-Lab sooner. Compared to a public company with investors screaming for growth, small private companies can continue to profitably service a small market. I'm sure Atari was more focused on survival instead of helping German professionals at that point - if you look at Atari's revenue and stock price in that time period, it was bleak.
  12. You're correct that the worst rise in consumer prices was during 1988 - but I was talking about the entire period from 1985-1990. Look at contract prices from 1984 to 1990 to get an idea what big companies were paying. Contract prices for RAM hit an all time low of $5.6/megabit at the start of 1985, just as the ST product line and prices were announced. Prices only started rising later in 1985, after mass production began - because US manufacturers were abandoning the market. Prices rose more in 1986 as a result of the Japan-US trade agreement, eventually leading to the RAM shortage in 1988 which caused that big consumer price shock you remember. Contract prices did not return to their low of $5.6/megabit until early 1990. It's easy to research this - because the memory shortage was the subject of several lawsuits and news articles, contract prices are well documented from that time period. I got that "low" number from the Commerce Department's report on memory chip dumping in 1985 where they quote contracts going for 35 cents/64Kb. Imagine buying 1MB for $45! Atari could, during the start of 520ST production. Prices were a lot worse by the time you got started in 1987. Yep, that was the joke. They couldn't slash prices as easily as they did on the XE/64, because they were unable to make a small RAM model of the ST. That didn't stop management from announcing those small RAM models anyway - but it's funny to imagine engineering reality raining on management's parade.
  13. Memory prices were also incredibly uncooperative. There was a huge RAM price crash in '85 - which is why the 130/260ST just evaporated and Atari was loudly bragging about "1024K for under $1000". After that, memory prices went UP for 5 straight years. Atari was hurting so bad they ran a RAM smuggling operation. One of my favorite links about that time period: http://www.atariarchives.org/atarileaks/ Maybe if they had hung onto that 130ST...
  14. Jack Tramiel was in business for a long time, and sold a huge number of products from typewriters, adding machines, pocket calculators, and at least a half dozen lines of (mutually incompatible) computers. I don't think he had a specific vision for the machine - he (and later Sam) were more focused on how to position products against the competitors - and which competitors were important. Leonard was much more involved in the technical decision making process, but there were a number of ex-Commodore people in the early days, and later Atari people who were more influential. Richard Miller is a key person from the era you're discussing - he was VP of R&D and helped define the Panther, Falcon, and Jaguar. It's not like Sam or Jack were saying, 'We need more colors and a DSP in the next one, sprites are not important.' They were saying, 'Let's see if we can boost ST sales, but don't put all our eggs in that basket. Instead, put $X into PC clones, $Y into ST, and $Z into videogames - and let's try a handheld on the cheap. Have it all ready to show for CES.' Then, R&D would come back with a handful of features they could implement inside that time and budget. I don't know the STE details, but I work on consumer products for a living - so I can tell you how features really get decided. Management needs the product for CES, and you lost that clever chip designer from before, and the new guy will take months to train, and nobody knows how half this stuff works anymore, plus the manufacturing cost has to go down. So, you better give up on your best ideas and keep it simple - or you'll miss the date and fail your mission altogether. I know this wasn't your exact question, but you can see how Atari struggled with strategy for a while. The ST strategy made sense at the time - we'll build a cheap competitor to the Mac and take all that sweet high-end Mac business - and the laser printer and Mega and TT030 are all examples of that approach. But after a few years, the network effects of an open (PC) standard were unbeatable. Atari tried to get into PCs, but by then, competition was already too intense. Handhelds were another promising area that Atari dabbled in (Portfolio), but they didn't invent the Palm Pilot. I think returning to videogames was a reasonable move. Plowing more R&D into the ST would have made us collectors happier, but would it help sales at that point? Who would write software for it? Atari noticed their customers were musicians and people in Europe looking for a cheap entry-level game machine. So, when the old Mac-attack strategy stopped working, they kept things cheap and threw a few bones to their customers - a smart way to milk the last dollars out of a legacy business. We can all do better as armchair CEOs, but I think the decisions make sense in that context.
  15. As a teenager, I briefly lived near an independent game store in northern Utah. (I think it was Fun Unlimited?) The owner would sometimes hang around the store and chat with the nerdier kids. He bragged about attending Atari's shareholder meetings and getting hands-on access to the Jaguar. He even showed us the VHS demo tapes and discussed the finer points of 64-bit graphics. Lynxes were popular at my high school - all from that guy's store. I got a Jaguar from his first batch in early 94. He claimed to have sold hundreds, stuck waiting on Atari for more. (That summer I got an internship programming games, and learned it's easier selling Jaguars to kids, than convincing my developers at work that Atari had a future - Sony was already dazzling.) I visited the store again in 96. The owner was stuck with some inventory, but remained convinced the JTS takeover was only a speedbump and the Jaguar would live on. It never occurred to me he might just be a good sales guy - saying whatever it took to sell what he had left. I walked out of there with a JagCD. He had a bunch. That part of Utah was a weird vortex of abandoned technology. The high school had Apple Lisas - in the early 90s - thanks to a local business (Sun Remarketing) selling them cheap as Mac-compatible. - KS
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