Altair 8800 - Video #3 - Kill the Bit Game
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- เผยแพร่เมื่อ 5 ก.พ. 2025
- Enter and run the famous "Kill the Bit" game for the Altair 8800. This program ran on the Altair's front panel and did not require a terminal or teletype. Support material for this video at altairclone.com....
I'm just at a loss for words with this! The fact that someone figured out how to fit what looks like legit fun gameplay into 16 lines of assembly is astonishing. What's the story behind the program, and who wrote it?
yeah, but can it play doom?
Jer Mi this already is Doom for the Altair xD
haha
Jer Mi I like how "can it play doom?" is way more appropriate than "can it play crysis?" in this case :)
It is not assembly, it is raw machine code. That is the author did a hand assembly and then wrote down the machine instructions.
I love how quickly it boots.
must have an SSD
@@Nupetiet technically true all solid state storage
Ah, this explains what Sulu and Chekov were doing during downtime on the U.S.S. Enterprise.
your videos are really great, you explain everything....like a basic guide to the altair, thanks for explaining and going through everything, very interesting!
Ha, this is actually really cool! I didn't go to the documentation PDF, but I did catch that you had a 303, a 10, and a 0 in sequence, and from the previous video I know that means to jump to memory location 10? I think I have that right... Either way though, it's pretty cool to see how this works, and how the computer actually reads and understands commands.
This really is cool though, it would be so awesome to have this program blinking away on a shelf or something when guests are over, and just amaze them when they ask what it's doing, haha.
Amazing and very interesting. It shows computer technology has made an enormous leap in technological development.
I love this video series!
Thank you for demonstrating that - totally fascinating!
Great to hear -- thanks for the feedback!
Awesome!
I'm waiting for the parts to build my own clone. Too bad the original one is too expensive, even as replica with modern components :-/
BTW I tried to input the "kill the bit" program in some emulators (I tried three of them) but it doesn't work (and I'm sure I input it right). Strange, isn't it?
This is a known issue with software emulators on the PC. Lots of them only emulate instructions, and not memory cycles, meaning the LEDs don't update accurately on those emulators.
Here you can see how fast the Technologie is geting better.
I am verry respectful to those who can run computers like this with all the Bits you must insert by your self.
Has anyone managed to get this to work on an PC emulator? I tried it on "Altair32 for Windows" but when I ran it the A3 light stays on, A2, A1, A0 flash but none of A4-A15 light up at all.
I've been having the same problem as well.
ditto me too. must be a crappy emulator. they probably figured no one would be patient enough to load any programs haha
It has something to do with the increased memory size.
Tried again and played around with some settings in the emulator but always the same result. Has anybody managed to get this to work?
@@D600Active it doesn't work in altair32 emulator, talked to Rich Cini , the programmer of this emulator says it doesn't work because of how the front panel is programmed, the front panel doesn't work exactly like a real altair, the data latches which are needed for kill the bit to work aren't implemented correctly in the altair32.
I have to admit that terminology about memory addresses is WAY over my head, but I have been getting interested in vintage computers recently. Even though this looks like a ton of work and extremely tedious, there is also something intriguing about it.
I was sadly unsucessfull to get it running on the s2js.com Simulator. Maybe I did something wrong? I triple checked the RAM hex dump and everything seem to be correct, starting with h021 at 0. Do you have any hint? Seems like the machine runs an endless loop between Address o008 and o015 while the address bits A4 to A15 are all dead...
Or does the simulation run to fast to just see any of the bits?
@@SebastianS72 i couldn't get it to work either and tbh i have no idea why that is :\
I had the same problem. The problem with the s2js is that it executes one instruction after the other while the original altair executes one Byte after the other. This basically means that some lights that would be active on an og would not be active on the s2js. (The program does actually execute correctly, you cant see it though)
What's the difference between 'just a reset' and a 'hold stop and reset'?
That's never made clear in the video, or maybe I missed something.
I think I figured it out: if 'stop' is not toggled before (or during a reset), the program counter will start running again right after the reset.
But what is meant by "the official way" at 5:09 though? Why is holding STOP and resetting "the official way" and just hitting reset the "unofficial way"?
It's the official way because that's the best way to stop the computer. A reset would not put the computer in Stop mode, so Stop & Reset was the way the machine was always stopped. Official is not the right word, it should just be said that it's the approved way to stop the computer. Much like shutting down your computer by clicking Start and Shutdown, vs just pulling the plug. Both work, just one is the approved way.
You confused me for a while because you say "Ten" and then enter OCTAL "10" which isn't really "ten" it's eight... I would call this "one, zero" to save confusion.
It is very common for programmers using primitive machine language coding to use shorthand nomenclature when talking in Octal or Hexadecimal, using wording as if it was on Decimal. The programmer knows what he means, and it is just faster and easier to say things like, "Ten" instead of "One Zero Octal" or "One Zero Hexadecimal".
Like programmers like to say, there are 10 kinds of people in the world.....
Those that understand binary, and those who don't.
still wondering how it works in Octal when LEDs can only be either 1 or 0.... on or off
This is why the switches are in groups of three. Three binary digits can store a value of 0-7 which can be easily represented in octal.
Octal is easier to write in your notebook than raw binary... human read/write errors are very very easy in binary.
coool! and the program is so short!!
oh, it's a clone. At first I was surprised he was flipping those switches that casually.
The real ALTAIR works the same, the switches are actually very robust.
This clone, using more modern tech, is virtually empty in that big box. The MPU and logic pcb is part of the front panel, along with the LEDs and switches.
What´s the OS ?
teltri It does not have one.
It doesn't come with an OS, but you could load one from disk or tape (you'll still have to key in the bootloader if you didn't have a special ROM card).
We are programming on the bare metal here.
I just toggled in grand theft auto, and then the power goes out! Man, I gotta get a UPS.
I've got a UPS, could you mail me the listing? lol
Ok..so that was the call of duty of 70s
Jesus christ that is a lot of work
Yes. Yes it is
This computer, with only those few LED lights and a CPU that ran at 2Mhz cost about the same as about 4 iPads
why octal?
Probably because the Intel 8080 machine code maps really well to octal.
For example, to load one register with the contents of another; the first octal digit is 1, the second octal digit specifies the destination register and the third octal digit specifies the source register.
I tried this(and failed on first try) using a virtual ALTAIR simulator s2js.com/altair/sim.html and had no luck with it. It's impossible to do a hard reset with this simulator as far as I know, but another thing I noticed, MEMR, MI and WO isn't lit up.
Great videos though! I really enjoy learning this stuff!
The problem with the s2js simulator is that it executes the code differently. It executes one instruction after the other white the original altair executes one BYTE after the other, so on the simulator some lights that would light up on an og would not light up on the s2js
Can it play my Black Ops III?
Will "can it play ..........." jokes ever become funny? Don't think so.
Why octal? Hex fits better into a byte.
calvinatorzcraft, Hex is more efficient, but it requires the use of A through F and humans are inherently not as good thinking of letters as numbers. Octal is less efficient, but because it is purely numeric, it is easier for humans to work with. But Hex and Octal are really converted to and from binary.
I typed to make this, but i got Kill The Bit Without the bit.
To me i typed inn the correct address, so i think it is the Emulator I'm using.
Mind blown
Just tried this :-)
but can it run minecraft?
what does it do?
it computes
please don't kill the bit, the bit did nothing wrong to hurt anyone.
Kids today with their iShits and mePhones
Ben Dillow Good for you
***** It's a joke calm down.
As the technology gets better, the users get more retarded.
+The Patriarchy So true!
The Patriarchy Ease of use made technology usable by more people, But took away some of the "magic". I guess that's why I still pound away at the DOS,er... Windows command line! Sure an electronically controlled automatic transmission of today is better at shifting gears than I am, But Dammit, driving a "stick" is fun! There is a certain thrill in doing it yourself at a certain level!🙌.
you are switching swtiches wayyyy too fast to understand
DOS Computers from the 90's were far more fun and interesting than this boring old switchbox. I was so bored I could'nt sit though the entire video. How can you play games without even a screen? I know, ooooh pretty lights! Lets switch 'em off and on one by one! hehe This is so fun!!!
its interesting even today because it is a piece of history. everything he is doing is programming the machine in assembly language. AL is the lowest level of computer programming possble. this machine represents all the basic functions of a computer which all modern machines are built on.
There's this thing called "this computer is from the seventies." If you don't want to mess with stuff of this vintage, don't watch the video.
LoL don't be so personal... I was just stating my opinion, that's all.
geo58impala, too bad your opinion is so uninformed and generally clueless, like a child who hears adult conversation and then comments that they are incomprehensible, boring, and not about ' fun stuff'.
Actually this is not "assembly language", it is "machine code". There's no high/low level language involved in the entry of the program.