Sunday, February 19, 2017

The Atari Game: GLIB by Mike Montana

This essay is printed here with the kind permission of the author, Mike Montana. Mike is the son of Rich Montana, who was the programmer of Glib for the Atari 2600. You can hear my interview with Mike in episode 134. I am indebted to Mike for all of his help with this episode. If you have any questions for Mike, please send them to me at 2600gamebygame@gmail.com, and I will make sure he gets them. Thank you for reading!


*********************************************************************************

Concept Genesis

Selchow & Righter are known for pretty much one thing – the classic board game “Scrabble,” where points are made by forming words drawn from random letter-tiles, each letter having a particular point value.

In the early 80s' execs at the company wanted to expand the brand into the marketing explosion "all things Atari." Friends of friends were contacted and ultimately Pete Farentinos of Qualtronic Devices in Smithtown Long Island was brought in. His company was selected as they were the regional distributor of Rockwell’s 6502 processor – which, as you know, is the CPU in the Atari 2600. Qualtronics and Selchow & Righter’s marketing people put together a game concept that was essentially Scrabble. Each player would be assigned 7 random letters, and together, in real time, they’d race to complete a word for the most points. Multiple players would run across a field of letters, grab one (thus denying the other player), and run the letter to the word-block (imagine Wheel of Fortune meets the Hunger Games) Variants on the idea were pushed around, and the game-concept was christened “Head of the Class”.

Qualtronics brought in Rich Montana of NJ to evaluate the feasibility of writing the game on the Atari. He had often worked with Qualtronics as their electronics-engineer for many 4 and 8 bit CPU related projects (Mattel’s hand-held football game was the Qualtronics/Montana team’s previous project, which was on a 4bit CPU).

Getting Technical

At the time, for consumer grade products with CPUs, there was no Operating System. There was no BIOS. There was often enough, no ROM with prebuilt functions for interfacing with the hardware. The Atari 2600 was as close to useless as such a product could be. No pre-packaged ROM set, no BIOS, meaning, there was no published API on how to write software for it. Writing software for it was more about understanding which interrupts were available, how to interface with the Sound and “Video” chip, and which bytes of zero-page memory were used by the hardware (and how it could be used). Knowing how to write software for the Atari was a closely guarded secret and the “SDK,” which was more of a collection of electronic parts data-sheets than a list of function pointers, was not public domain. It was available through Sunnyvale’s very expensive licensing. Key to getting the “Head of the Class” cartridge off the ground was getting that documentation. A few calls, a few wink winks, and a few weeks later a Xerox copied sub-set of somebody’s design documentation was delivered in a nondescript three-ring-binder to Rich so that he could begin. The cost of the Xerox copies and binder was a then-staggering $25,000.

Getting Started

After reading through the design-documents, and weighing the design constraints of 1982 technology, Rich looped back with the Marketing people and burst the bubble between “expectations” and “reality”. Cost was, and is, a driving factor in any product development. “High-Tech Consumer Products” were even more expensive – the typical Atari cartridge was 4k of ROM. This was the sweet spot of cost/availability/useful-size. Selchow&Righter weren’t looking to become a software-house. They wanted a product to expand the brand, and make some money. They were not interested in bank-switching ROM nonsense, and they were not interested in doubling the component cost by stepping up to the next available sized ROMs.  All these constraints made perfectly good sense.

Except: with 4k of ROM, there would simply be no room for a dictionary. The reality was clear – there’d be no way for the game to judge if the word created was legitimate. Probably a fatal flaw already, it was decided that the “other player” would “accept” or “reject” the formed word.

Except: if the “other” player was the judge on word acceptance, there could only be 1 active player at a time.  The Hunger Games would have to wait another 35 years.

Except: Atari’s player missile graphics had real hardware trouble with getting more than 8 “high-res” images to display on the same horizontal raster line. The 2600 has very limited number of display modes – “low-res” was something on the order of 20 blocks per scan-line, and the video-chip could do some basic modes such as "mirror right to left," “mirror top-to-bottom” without having to tie up the CPU/memory to describe the layout (which is why most every “maze” game is mirrored geometrically and very blocky). You could use this very-blocky mode to display score (such as the very early games with giant-score digits). Or, if you were clever enough to be careful with counting CPU cycles, you could use the video-chip’s “player missile graphics” to build text/digits out of the sprites, and then switch out of that sprite once the scan lines were beyond the “zone” of where you displayed text/digits. …so much for displaying a field of Scrabble tiles for players to race around and grab.

Except: the amount of RAM in this CPU was worse than “limited”. The CPU was a variant of the 6502 – with only 128 bytes of RAM. BUT, you don’t get 128 bytes. About 16 are actually controlled by the video/sound chips. Another block is the CPU’s stack. Each call to a subroutine would extend the stack’s memory use by 2 bytes, every PUSHX, PUSHA, PUSHY instruction would extend the stack by a byte.  As is typical in assembly programming, you would often push values onto the stack, jump to a subroutine, do some work, and depending on your philosophy you might POP the registers before returning, or after. And if you mixed your philosophies you’d easily blow the stack. Not a big deal right? You’d get a runtime exception of stack-corruption. Except this isn’t C code. There are no “exceptions.” You would destroy a return address on the stack, and on the return from subroutine you’d jump to an undefined location, and who knows what happens. Usually, just a hard lockup with an annoying sound on the TV set.

At this point the game probably should have been dropped. But, deals were made, documents were procured, campaigns were being formed.

Development Begins

Qualtronics, being a regional distributor for Rockwell International’s 6502, was also a distributor for their computer – the AIM-65. It was a 4k device, about the size of an APPLE-II, with a full-stroke keyboard, but, a 40 column scrolling LED display and a 40 column thermal printer. The unit wasn’t meant to be a “desktop” computer, it was more of a design-base for industrial control applications requiring a computer. As such, it was meant to be expanded in whatever application capacity would be useful. The full CPU bus was available as an expansion port. Rich started off with one of these AIM-65s as the development environment for the “Head of the Class” game.

However, it needed upgrades. First off a 3rd party dual-floppy drive system was purchased. To use the floppy drives, the case was opened, and two “expansion” ROMs were inserted into the C000-D000 sockets.  An 80 column Zenith VT-100 terminal became the 9600 baud TTY “development interface” as the AIM had no ability to drive a video monitor directly. A box of floppies was mail-ordered and would arrive sometime within a month as there was no way to retail purchase floppies in 1982. The Rockwell licensed Assembler Language was part of the package.

All that was needed was memory – every developer always needs more memory. There was no “memory expansion kit,” it had to be made. Development time was burned up handcrafting a 48k memory expansion. Data sheets were collected, schematics drawn up, a dozen or so RAM chips purchased,  and rather than wasting time having a one-off PCB board made, all the pins were manually made by wire-wrapping the interconnect of the two dozen wires per chip.

An ultra-violet lamp was purchased, and a sleeve of 27032 EPROMSs were purchased. A development target was selected – the family Atari 2600 was now commandeered to never return from Development Hell.

The Development Cycle

Typically, embedded systems are done with an “in-circuit emulator” which is a surgical replacement of the CPU with a connector that replicates all the CPU signals and branches them to an external controller so that code can be injected, debugged, and the system state can be programmed. However, no such in-circuit emulator was available for the Atari, and if it was available, it would have only been for Sunnyvale blessed developers. Instead, why not just create a cartridge, pop it in, test it and repeat until done.

Using an oscilloscope and data-sheets for the chips identified on the Atari motherboard, Rich found that all the data lines and address-lines for the CPU were brought out to the Atari cartridge port, and that in the end, the cartridge was merely a 4k ROM wired up in a standard Address bus/Data bus configuration. Meaning, just popping in another ROM was simple. The least liked family game (“Combat”) was chosen as the sacrifice. Its ROM chip was unsoldered, and a “rom socket” put in its place – this gave the ability to pop out the chip, and pop in another without needing to solder anything.

Code was written, compiled by ping-ponging source/object/binary files between the two floppy drives with a binary file that was put on to a ROM at the AIM-65 side. The ROM was popped into the surgically mutilated Combat cartridge, the Atari powered up, and the code was there to test by playing the game itself. If the game crashed, or hung, or didn’t go as planned, the only debugging tool was an oscilloscope to probe the data lines. Code would be changed, a new ROM generated, and a new cycle would begin.

EPROMs are the great-grandfather to flash-memory. They are the grand-father to “E-EPROMS.” Flash memory is permanent memory that can be changed under CPU control (like your SD cards used in phones – they don’t require power to keep the data retained). E-EPROMS are “Electrically-Erasable Programmable Read Only Memory” – which is similar in concept to Flash Memory, but to erase the memory a long tedious process was required. EPROMS, the most ancient, was “Erasable Programmable Read Only Memory” – and the only way to “erase” the data was to put the chips under intense ultra-violet light for an hour. The design of that generation of read-only memory was that all the E-EPROMS/EPROMS/ROMS were physically interchangeable. You could pop in a 2732 EPROM directly into the socket of a 4k ROM chip, thus an erasable PROM could be used directly in place of the original Combat ROM.

Programming the EPROM was nearly as slow as erasing one. To program the EPROM a “burner” board was required, and it was configured via a 9600 baud serial port. It would take 16 bytes at a time, burn them sequentially into the EPROM, and within a few seconds be ready for the next 16 bytes. Writing 4096 bytes would take several minutes. Development cycles were lengthy bouts of patience as there was no internet to be amused by while the chip was being burned.

Once it was realized that the ROM was a standard off the shelf 4k component that was directly accessible by the CPU, and all the hardware was already in place, it didn’t take much effort to wire up a cartridge receiver that could simply dump the contents of memory to disk, and copying friend’s Atari cartridges to disk was painless. Burning them back to EPROMS was painless. Having a library of dozens of Atari games, on a floppy, was a secret kind of joy known best by developers to this day.

Game development was slow, but, picked up as infrastructure code was developed around trying to understand the 2600 Design Document. The 6502 CPU ran at 1.8mhz, which was just barely enough to get things done. The electronic design of the 2600 was such that the CPU would receive an interrupt from the video circuitry saying “It is now time  to draw the screen,” and the CPU would have to set up the display mode chip, setup the player-missile-graphics, and “draw” the screen. Each assembly instruction takes up a fixed amount of time – some instructions would take 2 cycles, some would take up to 6 cycles. Each scan line of a TV takes about 55 microseconds. Each 6502 CPU cycle is approx. 1 microsecond, so on average, each assembly instruction is 4 microseconds. You don’t have a lot of time to do much once the scan line is started. Manually counting instruction cycles is required if you want to switch things up on the display, as its being drawn. Once the display is drawn, the interrupt is cleared, and the CPU code returns to ‘whatever it was doing before.’

In the case of Atari games, this “vertical blank time” is when scores are updated, enemies are moved, etc.

Finished game released to Manufacturing

Atari games are ROMs. An EPROM at the time was probably two or three dollars each. Whereas a ROM could be as cheap as a few cents each – if you had hundreds of thousands made. Making a ROM was a special process involving microscopic photography. When code was considered “finished” and ready for a ROM, the raw binary content was given to a ROM manufacturer. The manufacturer would make a series of photo-masks that represented, in literal physical terms, the 1’s and 0’s of the raw binary content. The raw “ROM Blank” was a slab of photo-reactive silicon alloys that, with a repeated series of photo-exposures and acid washes, would physically burn the data onto the chip. Once created it could not be changed. Once the photo-mask was created for a “run” it could not be changed. One incorrect bit, and the entire process would have to be repeated from the start. The ROM manufacturers weren’t interested in 100 units. Not even 5000 units was mutually worth the money. 10,000? Now you’re talking. 100,000? That’s where the per-unit costs get really cheap. It is best to buy in 100,000 unit quantities.

There was a long lead time on getting the finished binaries to the ROM manufacturers, the plastic cases ordered, the packaging created, and the marketing efforts ramped up. Much effort was put into play for the anticipated holiday rush. This was going to be Selchow&Righter’s splash back into Modern Family Life. Even if the game wasn’t as exciting as originally planned. Even if the game was actually not very much fun. It didn’t matter – the public wanted, and loved, all things Atari.

“Head of the Class” was developed and tested on the family 2600, played on neighbors 2600s to judge feedback and to verify it worked. The marketing folks long since dropped the “Head of the Class” name in favor of “Glib.” Delivered on time, the binaries made their way to the factories; cases were sourced; stickers, labels, and manuals were printed. It all came together and arrived on store shelves as planned. Tens of thousands of them all over the US in Sears, Kmart and Crazy Eddie.

Then the problems came in. It seemed that too many people simply couldn’t get the game to work – no matter how forcefully they blew into the cartridge. Kids across America were being scolded, “Did you put that tape near a magnet Johnny?! How many times did I tell you to be careful with them tapes!” No, it wasn’t a tape issue. No, it wasn’t a dust issue. It was a timing issue.

As it turned out, the “Xerox sub set of xeroxed design documents” was intended for European televisions. Recall how the CPU had to carefully count instruction cycles once the display interrupt started – being off by a few instructions would be wrong. The requirement that the CPU be tightly bound to the video-chip meant you had to be really careful on what you did, when, and for how long. Too many people (10% ? 20%? Something like that) were finding the display to be unstable, or rolling, or even just “freaking out” on their television sets. Technically, the timing was right on the edge of what would work on US televisions. Those televisions with the ability to handle overscan (which was new at the time) were the unexpected problem.

There was no way to deliver a “patch.” There was no way to “reprogram” the games. The only way to fix the situation was to create an entire new ROM, which meant another 100,000 ROMS. The customers wanted their money back. And the game wasn’t much fun anyway.

Realizing there wasn’t a financially viable avenue out of this, Selchow&Righter accepted returns. Only the returns weren’t from the 10 or 20% of the affected customers, they were the entire inventory from Sears, Kmart’s and Crazy Eddie’s. All the useless inventory was collected in a warehouse, written off as a loss, and never heard from again.

Timing is everything.

--

The Author: I’m Mike Montana, son of Rich Montana the developer. I was 14 at the time, and my father took me on as his apprentice and Chief Coffee Fetcher. He dumped the grunt-work of generating the hex-encoding of the player missile graphics to me, writing some small code (BCD math in assembly), and pretty much doing the drudgery he did not want to do - for which I thought I was the Coolest Kid in the World.  I learned how to do programming, soldering, debugging and how to copy Atari cartridges in this experience. This put me on the path of being the developer I am today some 35 years later.



Wednesday, February 15, 2017

87, Glib by Selchow and Righter!

This week I'm covering Glib by Selchow and Righter, the only released adult word game for the Atari 2600! I would like to offer a huge thank you to Mike Montana, the son of Glib programmer Rich Montana, for talking with me on this episode! I apologize for some buzzing during the interview, it did not sound like that during the recording. Mike was extremely nice to me and I'm so glad that he contacted me about Glib, in addition to telling me about his part in the programming. I will also be publishing a write up about Glib that Mike did, with his blessing. Thank you again Mike!

In two weeks I will be covering the homebrew game SCSIside/Ultra SCSIside, by Joe Grand. If you have any thoughts on this game, please send them to me at 2600gamebygame@gmail.com. Thank you so much for listening!

Pertinent Links

Random Terrain - Glib
No Swear Gamer 297 - Glib
Scrabble tile distributions and score values (English)
Don Sauter's Scrabble pages
8 Bit Workshop by Steven Hugg
Arcade USA - Q*Bert Minicade by Basic Fun

Wednesday, February 1, 2017

PB 5360, Q*Bert!

Thanks for your patience for this new episode on Q*Bert by Parker Brothers. Q*Bert is a fantastic arcade game and has a great port on the 2600, as well as many other systems! I hope you enjoy the episode. Next up in 2 weeks will be Glib by Selchow and Wrighter, the only adult word game released for the 2600 (I guess Hangman and Word Zapper are word games, but in my opinion they're skewed toward kids). If you've played Glib and would like to share your thoughts on the game, please send them to me at 2600gamebygame@gmail.com. Thank you so much for listening!

Pertinent LinQ*s

Tom Sloper's Sloperama
Tom Sloper interview by Scott Stilphen
Tom Sloper interview by CRV on Game Developer Research Institute's site
Q*Bert on KLOV
Random Terrain's Q*Bert page
Atari Age thread about gap in pyramid
Q*Bert 2600 arcade hack by RevEng
The No Swear Gamer 295 - Q*Bert!
SNES Podcast 4 - Q*Bert 3 with meeeeeeee
Arcade USA Minisode - Q*Bert!
Intellivisionaries Podcast 11 - Q*Bert, again with me!
Kenner Q*Bert 5 pack figure auction
Arcade USA Q*Bert Minicade by Basic Fun
Atari 2600 Homebrew Facebook group

Wednesday, January 11, 2017

MT 5659, Space Attack!

In this episode I discuss the M Network game Space Attack, which is the 2600 version of Intellivision's Space Battle. Coming up next is Q*Bert, which I'm sure some of you have heard of. If you'd like to submit feedback on Q*Bert or any other game I've already covered, please send it to me at 2600gamebygame@gmail.com. Thank you so much for listening!

Retro Gaming Discussion Show A to Zed of the Atari 2600
Space Attack on Random Terrain's site
Hal Finney interview by Scott Stilphen
Sea Battle for the 2600
Favorite Atari 2600 Games of Willie! Space Attack
The No Swear Gamer 281 - Space Attack

Sunday, January 1, 2017

2016 Year in Review!

Happy New Year! I was hoping to get this out before 2017, but we had super extenuating circumstances that prevented that from happening. Sarah and I played through all the games that I covered in 2016, some of which I couldn't remember everything about, but that was kind of the point. I have forgotten many of the games I've covered, so going forward I think this will be a yearly tradition of helping me remember. Like I said in the show, listening on an AUDIO podcast to people playing VIDEO games may not be everyone's cup of tea, so you have been warned. All in all it was a fun way to celebrate New Year's Eve! I wish you all health and happiness for 2017, thank you for sticking with me for so long. I will see you very soon!

Wednesday, December 21, 2016

2016 Christmas Spectacular!

Thank you to Kevin Zerbe for his recording of "Joy To The World" which opens the show. Thank you also to all the other artists whose songs I borrowed as a bed. Sorry.

Merry Christmas, Happy Hanukkah, Happy Kwanzaa, and everything in between. I hope your end of year celebrations are wonderful.

From the bottom of my heart, thank you. I love all of you.

Please be kind to one another.

-- Ferg

Wednesday, December 14, 2016

2656, Mr. Do!

Hello all, this week I talk almost all about Mr. Do! I recorded it in a fragmented way, so I have forgotten stuff and repeated myself, but it is out a little early, so there's that. One thing I forgot to mention is the game over screen, just a simple screen with Mr. Do and game over on the screen, but I don't think I've seen much of that yet. Matt brought it up in his email but it still flew right by me. Also, the PAL version of the game shows your extra Mr. Do!s as full bodies, instead of just a head in the US version. Curioser and curioser. Despite this I really hope yopu enjoy the show.

If you'd like to send in a Christmas memory, you have until the 17th to do so, and that episode will probably be out on Wednesday. The three days after for me will be eat, sleep, and work, not necessarily in that order. It's usually pretty hectic and I won't have much time for anything those three days. Also, Space Battle will be coming up sometime in January, please watch Facebook and Twitter for that. You can send your feedback to me at 2600gamebygame@gmail.com. Thank you so much for listening!

Pertinent Links

Mr. Do on KLOV
Mr. Do! arcade prototype footage
Mr. Do! on Random Terrain's site
Arcade USA - Mr. Do!
No Swear Gamer 285 - Mr. Do!
Colecovisions Podcast 22 - Mr. Do! and Dig Dug
Classic Gaming Bookcast by Chris Federico for FREE!
Willie's 3000 Subscriber Contest Video on Arcade USA
Shinto's Game by Game Podcast hub (it's .com, not .net, sorry Shinto)
The Retrogaming Times bi-monthly online magazine

Wednesday, November 30, 2016

AX-025, Keystone Kapers!

Happy Gluttonous Shopping Season everyone! Please be sure to visit your local mom and pop stores this season, they'll feel good and you will too. Today I am discussing Keystone Kapers by the one and only Activision! I apologize for the refrigerator this episode, it sounded really loud and distracting on my end, so I hope you don't hear it. Next up on the show will be Mr. Do by Coleco, and I'll also throw in 3 Coleco games that had part numbers but never made it to programming, at least not that we know of. If you have any comments on Mr. Do or any game I've already covered (say, Mousetrap fer instance), please send it to me at 2600gamebygame@gmail.com. Also, if you have any Christmas or holiday memories of really any kind that you'd like to share, I would love to hear them! Please send those to me by December 16th. Thank you for listening everyone!

Egg Nog (makes 1 gallon, cut it down to the quantity you like)

2 quarts half and half
1 dozen eggs (I use large)
1 tablespoon vanilla extract (DON'T USE THE FAKE STUFF, I WILL FIND YOU)
1 1/2 teaspoons salt
2 cups sugar
1 cup rum
1 cup brandy
1 cup bourbon

Beat eggs in a blender until frothy and lemon yellow colored. Add sugar, vanilla, and salt and blend well. Pour into a large container (save your gallon milk jugs!) and add the remaining ingredients. Shake well to combine. PUT THE CAP ON FIRST. Sprinkle some nutmeg in there if you like that. Do NOT sprinkle pumpkin pie spice in there (see vanilla extract). Don't worry about cooking it, all of the alcohol will take care of whatever salmonella is in the eggs. I'm still here, aren't I? Refrigerate unused portion and shake well before you serve it again. Unused portion, that's a good one. Enjoy! :)


Pertinent Links

Batteries Not Included show with Garry Kitchen
Keystone Kapers on Atari Protos
Keystone Kapers scratch card from Atarimania
Keystone Kapers 2 entry on Digital Press Rarity Guide
Activisions Spring 1983 issue on Atari Age
KK patch on DP
KK patch accompanying letter
Play Block the Knight by Rex Allison right in your browser!
Atari Flashback Portable Compatibility List from AA

Wednesday, November 2, 2016

GCG1001T, Music Machine!

This week I discuss one of the two religious games released for the 2600, Music Machine by Sparrow. It's an expensive game but worth your time if you use emulators or Harmony cartridges. Next, uh, time on the show, I will be talking about Crazy Climber by Atari, one of the Atari Age magazine mailaway exclusive games. So yeah, another rare game, I promise I did not plan that! If you have feedback for Crazy Climber, you can send it to me at 2600gamebygame@gmail.com. Please be sure to join me this weekend for Extra Life, and if you can donate, there are plenty of people to choose from in the links! Thanks to all who donated, and I thank you all for listening. I hope you had a Happy Halloween!

Pertinent Links

Palmtex/Super Micro Cartridge based system
Sparrow Records today
Peter Engelbrite's Music Machine page
2009 Kotaku article about sealed copy on eBay
2013 eBay auction for sealed copy
Video from above auction
Stella at 20 on Internet Archive
Art of Atari by Tim Lapetino
My Extra Life donation page
Rick's Extra Life donation page
Wade's Extra Life donation page
Bill's Atari Party Extra Life donation page
Marc Allie's Extra Life donation page