Altair at 50: Remembering the first Personal Computer
48 comments
·May 2, 2025NoSalt
pipes
Bill Gates goes into this in his autobiography, source code. Paints a very positive picture of him.
shakna
I was completely distracted by the magazine cover. The calculator being advertised there, and the wording, caught my attention.
The magazine issued is available here [0].
Apparently, it really was wiring up an entire calculator.
> ... Start assembly by installing and soldering into place the fixed resistors. Then proceed to installing the three electrolytic capacitors, the diodes, and the transistors, taking care to observe proper polarity and basing. Mount the transistors close to the board’s surface...
hvs
Until microcomputer boom of the 70's and 80's there was the calculator boom of the early 70's. The availability of the microprocessor made small calculators widely available for the first time and they were very popular among the type of people that probably would've read Hacker News had it existed.
Sharlin
What caught my eye was the headline about CCDs as successors to video camera tubes. Charge-coupled devices being, of course, the sensor technology now used by essentially all of the billions of digital cameras on the planet.
embedded_hiker
My school library ( 6th - 8th grades ) had this magazine, and they had a 9-week class on programming in BASIC using a 110 bps teletype connected to an HP2000C that was shared by several school districts. That was my start in all of this. I didn't get my own computer until the C64 price dropped to $200 in 1983.
CarVac
My dad has an IMSAI 8080 which is a neat piece of hardware. It still works, though a few LEDs failed.
Unfortunately for him, in university one of his professors advised him not to go into computers for a career...
kabdib
in 1977 or so my dad (a college professor) advised me not to go into computers
a couple of decades later (i hadn't listened, and had been working for high-tech Silly Valley for quite a while) he apologized :-)
danbruc
Cost the equivalent of $2359 back then, right now you can get a few on eBay for around $5000. Or you can get a mini replica kit for $150. [1]
twoodfin
Lest you worry you (or your parents) should have stashed away a few Altairs, that $397 in a tax-advantaged retirement account investing in the S&P 500 would be worth more than $70k today.
downut
I cannot find it but I think for about a decade the music cart rotation at WREK was powered by a student built automation system on an Altair. Don't remember any faults in the years I was around it.
(I was a music director at WREK in the early '80s)
jodydonetti
Olivetti P101 (1965)
pan69
It's an interesting one. Some people call it a Personal Computer others call it a calculator. However you classify it, it was certainly a interesting and important stepping stone and it's a shame that a lot of European innovations are often forgotten or skimmed over:
mrcwinn
For those interested in Ed Roberts, refer to Robert Cringely's "Triumph of the Nerds," in particular Volume 1.
igtztorrero
The Altair didn’t survive for very long, but essentially being responsible for the creation of Microsoft is a pretty Big Deal.
Bill Gates: "Popular Electronics" magazine cover of January 1975 change my life"
Paul Allen write the simulator on Harvard PDP-10, Bill Gates write main code of Basic, Monte Davidoff write Math package. They coded day and night during 2 months.
Micro-Soft was born.
JSR_FDED
Similarly it inspired the start of Apple!
rbanffy
Apple got a couple things right - the II had a keyboard, TV output with graphics, and plug-and-play slots (no fiddling with jumpers and dip switches like s-100 and PCs): each card had a well defined space for IO and ROM.
thesuitonym
Note that the Apple I was a kit computer that didn't come with anything other than the board and the chips. Not even a case! It's not really like Jobs and Woz had the brilliant idea that nobody had thought of before to include the accessories, it's just that the prices had come down to the point where a person wouldn't balk at buying a preassembled computer with a keyboard, display and a couple of floppy drives.
dowager_dan99
and the fact that MITS couldn't keep up with demand gave birth (IMO) to the 3rd party (licensed and unofficial) peripherals ecosystem.
reaperducer
Altair didn’t survive for very long,
The company sold itself to Pertec for what was a very good amount of money back then.
In HN terms, it was a successful unicorn bro exit.
dowager_dan99
and if I remember it correctly Roberts used the money to buy a peanut farm? Is that equivalent to a tech bro buying the coast of California or an island?
bbarnett
Did he use all the money, or some?
berlinbrowndev
Cool I always thought the first PCs were like the TRS or Commodore 64 computers.
rbanffy
There is some controversy - you could actually use a TRS-80, an Apple II or a PET right after taking it out of the box.
I think that, if we define a personal computer as a machine that is designed for a single interactive user, the LGP-30 would be a good candidate. It was not, however, a home computer.
For me, a personal computer needs more than switches and LEDs as its UI. With a serial port, a terminal, and a monitor program in ROM, the Altair would qualify.
dowager_dan99
keep the historical context in mind. There were people who wanted a computer at home and people who wanted to bring home the experience they got with access to powerful mainframe & minicomputers at work or school, so there was both a push to build your own computer and a desire to build IO devices like teletypes. The combo, all-in-one is the real revolution (IMO) that you got with the Apple II or the Sol. The TRS-80s and PETs feel a lot more like early commercialization in comparison. Woz was motivated by showing off what he could create, because that's how he communicated. It makes sense that a keyboard and TV - with graphics - shows off way better, same with being able to program in basic "... for $300 you can build a computer that's so good you can type programs on it and run them..."
SoftTalker
Did it not have a serial port? Would have assumed that connecting it to a terminal or teletype was the standard thing.
whartung
My first computing experience was with an IMSAI 8080 that class assembled the year before.
It had a keyboard and video board, rather than a terminal. The monitor was open chassis to boot (ah the old days when we didn’t protect children from lethal electricity).
It had a ROM monitor and cassette tape. You had to type in (in hex) a short machine language program into the monitor to load BASIC from a cassette. We simply never turned it off.
I tried ti enter the bootstrap through the front panel once, but I made some mistake, and it didn’t work. It was an awful enough experience I never tried again.
ebruchez
One of the interesting aspects of the Altair was that it was based on a bus called the S-100 bus. You would have a CPU card and a memory card at least, but everything else was optional. The serial board was separate, and strictly not absolutely necessary to play with the computer, since you could enter simple programs directly from the front panel.
maj0rhn
We had an Altair at home, that my father assembled from a kit. That version did not have a serial port. It had only the switches on the front panel. I did succeed in inputting some programs and in having them run. But of course it was appallingly limited.
The serial port was its own separate board. https://www.youtube.com/watch?v=RaYTd3dbXeM
There were two very clever I/O ideas that emerged for the Altair: (1) A radio on top of the housing would pick up a signal, allowing audio output! (2) A cassette tape recorder could be used as an external storage device, though I forget how it interfaced... the serial board, I think.
anthk
TRS-80, AII and the PET came later. You were right on the peripherals. Instead of a serial port, I'd set a TV output with a keyboard as an input, and the Altair would get far more sales.
SoftTalker
A TV output means you need to create (and have memory dedicated to) the video. A serial port is much simpler.
fortran77
The people I know who put together Altairs in 1975 used ASR-33 teletypes as terminals to run BASIC.
rahen
"Personal computer" can refer either to a small-form computer, in which case the Olivetti P101 was likely the first in 1965 (the PDP-8/E was also a contender), or to a microprocessor-based computer, in which case the Micral N holds that title in 1973.
The Altair, in 1975, was the first commercially successful personal microcomputer.
chasil
The Intel line was fathered by the Datapoint 2200; they implemented the CPU in TTL logic boards.
https://en.m.wikipedia.org/wiki/Datapoint_2200
The 6502 line came out Motorola's failure to "indulge" their employees in a low-cost 6800, thus unintentionally fathering MOS Technologies.
https://en.m.wikipedia.org/wiki/MOS_Technology_6502
The 6502 was extremely inexpensive. The first implementation was the KIM-1, so this is the first on that side.
Pet_Ant
You might want to look at the Sol-20, Micral N, and Kenbak-1 as well. From 1971, the Kenbak was a _personal_ computer, but not a personal _micro_ computer.
The Wang 2200 looks most like we'd expect a personal computer to look like, but the price range was not home-friendly (~$50k today).
mixmastamyk
Commodore had the PET in the late 70's, and the Vic-20 before the 64 in the early 80s.
Apple had the II in the late 70s, and before that was the Altair.
Wow ... the man who invented it, Ed Roberts, had quite the life:
https://en.wikipedia.org/wiki/Ed_Roberts_(computer_engineer)