Altair 8800 - Flashing LEDS or Lights as only output and over 5000 sold

[DaveLembke]

I like checking out the "Todays Computer Words" here at Computer Hope... and today this caught my eye. What stood out to me was that the only form of output was LEDs or lights that would light in a sequence from a switch programmed program to run. It got me thinking..... what real world use could this primitive and limited ability computer have had other than being used for people wanting to see different patterns of LEDs or lights chasing each other on this light display. To me the only way this could ever have been used for anything really beneficial beyond that of a conversation piece and something for people to build and tinker with to understand how a computer works would be if it had a real world application. To me having a metal panel with 36 LEDs and being able to program it with switch positions for binary input and store the values to run a program just seems so limited when not able to be directly tied into other electronics without performing a hardware mod to this such as with optocouplers to use the LED light output as a driver to enable or disable something in which it then could be used for automation controls to flip a relay on or off etc and hopefully another that controls a fail safe safety loop so that if the program malfunctions you dont have a machine that self mutilates itself with conflict of robotic arms etc trying to occupy the same space etc.

To me I always thought that that Altair 8800 had a serial interface so that it could be tied to other electronics, so that it could be used to perform redundant operations such as for automation. But to my surprise its more of a calculator than a computer given its by design handicap to use within itself without electronics modifications to customize it for an alternate purpose other than watching blinking or sequential LEDs or clock stepping 1 tick at a time to perform some sort of calculation and write down each LED read out of lit of not lit for 1's and 0's.

Looked on google for uses that Altair 8800 had and come up short. So maybe it was just a hobbyist box for tinkering and learning on vs for a purpose that is like how computers have been used for the last 30+ years in automation with serial and parallel I/O etc. 

My first computer was a Tandy TRS-80 Model 1 with 16k RAM, and so I have just about always had a computer that had a keyboard and display, and a ability for serial I/O so that I could control something else with my computer or at least a display with text even if just black and white was so much better than blinking lights to play games like Zork on it and program games with ASCII characters acting as a [ A ] for space ship and [ . ] for the shots fired etc and certain keys used to control ship and shoot etc which made for games like Asteroids a fun programming experience that after taking all that time to make up the game or program someone elses out of a magazine article, that if it was programmed without typo that you then had a game to play for free as many times as you wanted, as well as could go back into the game and mess with values and see cause and effect to learn what controls what etc.

However I did buy at a yard sale 20 years ago, a computer kit from the 1970s that had a bunch of buttons on it and a quadrant of 16 LEDS and you could program this computer that was battery operated to perform abacus counting and patterns etc, but that was just about all it could do with the RED LEDs and so, I quickly lost interest in it after playing with it for a bit. It was similar to the Radio Shack 150 in 1 kits where it had a pressed cardboard surface and plastic with LEDS poking through it and a bunch of buttons and a booklet that came with it that gave you a list of how to program it and operate it etc. It was lightly used and I could see why, the original owner likely spent about the same amount of time as I did with it and said woopdee-doo ok now im bored, and set it into the closet for 20 years until it made its way to yardsale, but batteries removed from it to be used in something else vs left to have battery compartment rot like other old electronic toys that I come by at yard sales so often have or the extremely rare event of opening battery compartment and 40 year old Panasonic Batteries that didnt leak!  In which I then save those old batteries cause I am weird that way i guess to like old batteries that dont leak in their old style appearance even though they are dead cells.

To think that computers with primitive LED Light read out display were also built at the same time that computers with ability to do stuff more visually entertaining to a CRT display such as PONG were going on, it just seems like they should have designed the Altair 8800 with even the ability to tie into a TV set on channel 3 for example and give it a keyboard as for lights and switches with computers is like 1940s through the 1960s computing when running a program for military or explorative purpose of a bomb coordinate or trajectory of whatever is going somewhere up in the sky calculated without taking days, months, or years with sliderules. 

Altair

The Altair or Altair 8800 computer from MITS was developed by Henry Edward Roberts and introduced on December 19, 1974. It was later published on the front cover of Popular Electronics in 1975 making it almost instantly a huge success. The Altair 8800 included an Intel 8080 processor, "1024 word" memory boards with 256 bytes of memory (expandable to 64 K). It was available as a kit for $439 or assembled for $621 and had several additional add-ons such as a memory board and interface boards.

Altair 8800 Computer

By August 1975, over 5,000 Altair 8800 personal computers were sold and started the personal computer revolution.
How did the user use the Altair 8800 computer?

The Altair did not come with a keyboard, monitor, or printer and got its input from switches on the front of the computer to represent either a 0 or a 1 and got output from flashing lights.

http://www.computerhope.com/jargon/a/altair.htm

[Geek-9pm]

To me I always thought that that Altair 8800 had a serial interface so that it could be tied to other electronics, so that it could be used to perform redundant operations such as for automation. But to my surprise its more of a calculator than a computer given its by design handicap to use within itself without electronics modifications to customize it.

It was my first home-built computer. I would have to program if from the front panel. The kit was sold at the lowest possible cost and still have a case. It had several 100 pin expansion slots. You sound buy cards. A memory card was needed. I bought a 16 K. Yes, that is  K, not M.
For program storage, a cassette card was added. Microsoft sold cassette tapes with BASIC  on 300 baud cassette. To make it complete, a serial I/O o board was purchased.
Oh, forgot to mention. One Teletype** machine.
Later I bought a EPROM reader card and wrote my cassette loader into EPROM.
Had to do it myself..
*
https://en.wikipedia.org/wiki/Teletype_Corporation

The Teletype Corporation, a part of American Telephone and Telegraph Company's Western Electric manufacturing arm since 1930, came into being in 1928 when the Morkrum-Kleinschmidt Company changed its name to the name of its trademark equipment.[1] Teletype Corporation, of Skokie, Illinois, was responsible for the research, development and manufacture of data and record communications equipment, but it is primarily remembered for the manufacture of electromechanical teleprinters.
...

Mine did not have the paper punch and reader. I saved my programs on cassette tapes. At 300 baud it beat the Teletype 110 baud. 

[DaveLembke]

Cool    Thanks for clarifying that the Altair 8800 wasnt as crippled as the Computer Hope description made it out to be with:

The Altair did not come with a keyboard, monitor, or printer and got its input from switches on the front of the computer to represent either a 0 or a 1 and got output from flashing lights.

[Geek-9pm]

Some users  would get the Altair with only memory and one I/O board. The I/O would be set to 110 baud in hardware. A Teletype machine typically had a 20 MA serial interface.With a paper punch and reader, one could load programs with paper tape.
https://en.wikipedia.org/wiki/Punched_tape

The tapes in the photo are  8 bit.

After awhile I got a primitive video display card that was monochrome and  only displayed ASCII. No images. I made a home brew parallel port inpour for a parallel  interface keyboard I found. I had to write my own thing for scroll and line feed. The video took a small part of the upper memory space of the 8080 CPU.

[DaveLembke]

Never played with paper tape. For me it was 5.25" floppies at I think maximum storage of 160k, and cassette loads with my TRS-80 model 1 with 16k RAM. 

Pretty cool that you did some mod upgrades to yours.

Back in the day the magazines use to have at your own risk upgrades and mods. I never modded my TRS-80 Model 1, but remember that you could bring it to Radio Shack and pay to have a mod performed in accordance to the TRS-80 magazine mod. Most of the time it was just user submitted programs that were approved to be shared to the community of other TRS-80 computer users through the magazine, but sometimes it would have stuff like add a capacitor here and cut this trace and add a resistor and add wire wrap wire from resistor to a leg of a chip as a pull up etc with black and white pictures showing the inside of the TRS-80 in respect to the modification completed and a schematic etc.

The expansion module that connected to the model 1 with ribbon cables I remember had more mods for it, but its been over 30 years since I messed with that to be able to say what they were in any detail and like I said I didnt mess with modding because I was young and feared I would cook something and be out of a computer. The TRS-80 model 1 I got in 1983 from a business 5 blocks from my home that had them all piled out by the dumpster, they upgraded to get rid of these TRS-80 model 1's that had a label on them dated manufactured in 1978 etc. As I was caught trash picking out a computer a IT guy there came out and assisted me in what i needed what cables and what was the best of the pieces to assemble a good computer at home, and I drove my bike back and forth between home and the business to collect all the pieces and assemble it at home after the guy drew up what plugs go where etc, and he gave me booklets of cassettes with software and a box of 5.25" floppies for it. Not bad for a free computer that worked and to learn Basic on when computers werent cheap back then. 

Friends uncle that also had a TRS-80 gave me the prior months TRS-80 magazine editions, programs and info still good in the magazines and free. 

[Geek-9pm]

So long ago... But I do remember the TRS-0.
about that time the electronics manufacturing compiles were stating to use micro computers with the power of the TRS-80.
When I went to work at Dysan, they were starting to use rack mount 8080 machines programmed in EPROM. No floppy disk. One of my jobs was to design a floppy disk control for the thing. It was a 12 inch floppy.Before you turn of the CPU you had to open the floppy drive door. Otherwise the power off spike would write to the floppy. That changed when the five inch floppies become common.