Finished secondary school whilst waiting for it to be delivered, it arrived the following week - the first week of June 1981.
I spent the intervening months teaching myself BASIC programming from the total of 3 books on programming in the local library.
I remember the day it arrived well; I was busy cleaning house and didn't realise the postman had left the parcel in the kitchen until I stopped for a break a couple of hours later.
Had it unboxed and connected in a flash and I was still to be found lying on the lounge carpet in front of the television programming it (in BASIC) at midnight.
Started my agricultural apprenticeship the following week and continued programming late into the nights, quickly moving to write pure Z80 assembly language code.
Dropped the apprenticeship a year later, went self-employed, and been hacking ever since.
I still miss those days of actually counting the clock cycles of different instruction combinations to find the most efficient code via the look-up tables in the back of Rodnay Zak's "Programming the Z80".
Oh, and we had to manually enter the hex codes of the instructions to write those programs - before there was a decent assembler available.
I recall adding a full-size mechanical keyboard, a 16KB RAM-pack, and a weird multi-port expansion dock that had add-on modules (like a light pen) built into cassette tape cases and connected via a single-in-line pin connection.
I still have that original ZX81 along with a UHF<->VGA signal adapter. Time to fetch it out of its shoe box and fire up the nostalgia.
Also, the official manuals had some of the best cover art ever seen on a computer book, by science fiction artist John Harris:
To give an idea of the state of computing back then, the manual states (I checked now)
> to get '+' you must hold down the key SHIFT and while you are still doing that, press the key K.
Not something you find in user manuals now.
My English was so bad back them that I couldn't understand the full meaning of the sentence and I couldn't go through the example. I asked my classmates at school the day after. My mother was a touch typist but she didn't realize that the tiny keyboard of the ZX81 could work like the one of a typewriter. Computers were beyond geeky.
Indeed, perhaps mostly because user manuals themselves are not something you often find now.
Here is a link to official free copy of this book:
Gameplay of R-Type on ZX Spectrum:
I'm still playing ZX Spectrum games once in a while in the urge of nostalgia.
Me too. Was playing Horace Goes Skiing earlier this week, but my all time favourite game is "Chaos: The Battle of Wizards":
(This is available to play in your browser, online. Fun!)
Back in the day I used to hack games for infinite lives, and received a bunch of swag from Your Sinclair, and Sinclair User for posting them.
I credit the 48k Spectrum with getting me into programming, first BASIC then Z80 machine code. (Largely because the "bundle" we received had a dead tape-deck, so for the first couple of weeks the only thing we could do with it was read the manual(s) and type in simple programs..)
For example using the cycles while the beam was moving from the bottom right to the top left to start a new image to do non-graphical work.
Great little machine, and introduced me to programming in ATOM Basic and 6502 assembly, leading to a career in computing that's still going 30+ years later.
Oddly enough, I just ordered parts from Mouser to build David Johnson Davies' Tiny Lisp Computer 2, ... DJD being the author of ATOMIC Theory and Practice and Practical Programs for the BBC Computer and ACORN ATOM.
Sadly, my parents dumped it (and my two ZX Spectrums), but I still have one of the manuals squirreled away.
Edit: JS emulator, for that extra touch of nostalgia
I did learn a lot about modern day programming, though. Everything I wrote was really just copy/"pasted" from a book or magazine.
But no I don't have the TV to plug it in!
(More here: https://www.vintage-radio.net/forum/showthread.php?t=73664)
I really wanted an Atari video game console but my parents thought the ZX81 would be more educational. And I guess they were right.
Endless hours on the floor in front of the TV writing programs in Basic with that spiral bound user's manual for reference. I got the 16KB expansion pack since the 1KB grew old pretty fast.
I remember the user's manual had the pins for the expansion port and a list of all the Z80A assembly instructions. I spent hours looking at those having absolutely no clue what that was. No Internet to look things up back...
I also upgraded to the Spectrum. An then surprisingly enough to an Atari 512ST after the next Sinclair, the "QL", turned up to be a bit of a fail. Really should have gotten an Amiga in retrospects ;)
A number (in source code) used a lot of memory, 6 bytes or so, while a command used only 2 bytes, so you would replace numbers by VAL("1") or ORD("A") or something along those lines, saving a full 3 bytes... :-)
However, video memory ate into your 1k RAM. At 24 lines of 32 characters, a conventional video memory would need 75% of that 1k bytes, so they did things differently; video memory was laid out as you would do in a text editor, with each line ending in a line separator character.
That way, an empty screen took just 24 bytes, a full one (32x24) + 24 = 792 bytes, leaving 232 bytes for a program.
=> few programs for the 1k version could use the full screen.
The particular trick that enabled the program to use the last two lines was easy to come by (I was in the countryside, hundreds of kilometers from the nearest user group, and I only had a few books as source of information). The existence of such tricks, including the pure software “hi-res” more that I read about at the time but didn't get to see until the Internet made it possible 12 years later, is one of my fond memories of that era.
I couldn't get the cassette storage to work, so for several days, I begged my family to not unplug it. I remember one amusing thing about its architecture, which was that it used the CPU for video generation, and did all of its execution of BASIC programs during the vertical blanking interval.
My own first computer was a Spectrum, which I loved, but I didn't have access to a colour TV at the time. I got to know all the fancy colour games in black and white.
I didn't know anyone who owned one personally, but that was probably an income-based observation.
I used those at school and liked them a lot but, I guess like the Apple II, nobody would have bought one for their home because they were expensive and sold mostly through education channels.
In the 80s they generally switched to BBC Micros, which were affordable enough that some better-off families had their own.
So I can see it being a regional thing that I never used an Apple II -- they didn't appear in schools in the UK -- but I wonder about other countries besides the US. Was the Apple all that widespread anywhere else?
(I'm fairly sure the Franklin Ace was available over here as well; at least it appeared in listings at the back of computer mags I used to get. I never saw one and, at the time, never registered that it was an Apple clone.)
So many things came together back then. On TV I saw a documentary about kids in Japan writing their own games. In our city's airport there was a advertising installation for the IBM PC (forgot which model exactly) in form of a lunar lander game. And my best friend in school had just signed up for a BASIC course taught by students of the local university.
I remember I sat there next to the phone going back and forth, unsure about whether I should do the BASIC course and get one of those strange computers myself, or not. Almost didn't do it.
When I did finally decide it basically set me on the path for my entire career continuing to today.
Of course the first thing I did was figuring out how to do the lunar lander (today I know what I did was the Euler Method).
Edit: I also remember I had a hand-written Z80 op code table of 256 op codes. Using that I would write machine code.
 Though there was 1K chess, a mostly complete chess game in 672 bytes https://en.wikipedia.org/wiki/1K_ZX_Chess
Oh, that wobble! Definitely on my short list of the most annoying hardware problems in computing history. You’d spend ages typing in the code for a game from your book, and then just as you were ready to go…
The GPUs of budget phones have 10's of GFLOPS... to make a comparison with the ZX81, what's the fastest Z80 routine you could write to multiply 32-bit floating point numbers? Or perhaps, how fast is the routine in the ZX81 ROM BASIC (by Steve Vickers)?
Thw ZX81 had a 4MHz Z80, but in "slow" mode, about 3/4 of that was occupied in rendering the screen, making it effectively 1MHz. In "fast" mode, the screen went black...
Does anyone remember the MSX series of computers from various vendors?
It's a pretty cool piece of history though. How many people can say they still have their first computer?