Sinclair User Jul 1982: ZX81 and Spectrum hardware comparison. Amateur radio feature. ZX81 assembler round-up. Rainbow Computing interview, featuring two people who developed the Spectrum. Game reviews column has disappeared and slightly (1/2)

This is incredible! Can't wait to see them in August. youtube.com/watch?v=UAno...

“So if you have bought several ZX Microdrives, you can FORMAT your spare demonstration cartridges and use them as blank cartridges.” - but i had the 1983 and the 1984 demo cartridges and lost the more capable 1984 cartridge by heeding this device.

So you think you know Sinclair BASIC? Without running this on a real Speccy, what will this program output, and why?

I hope you used smart algorithm like the one described by Toni Baker 😁! github.com/markgbeckett...

How old school Tape Loading worked. lemmings.info/how-tape-loa...

On Page 30 my 255 byte UDG Editor which squeezed into the ever present printer buffer. Submitted to the magazine in June 1985 long before the news of the 128K ZX Spectrum hit the streets. The printer buffer was used for extra system variable purposes and using the buffer was henceforth verboten.

ZX Format Fanzine READ: https://archive.org/stream/NH2021_ZXF10.pdf/page/n00/mode/2up

This 50 year old Sedgefield company is set to soar after a long Bank Holiday break in trading. The price closed in US at $5 minutes after this video was posted. OTC trades in US start nowish but the biggest shock will be as the UK joins the party tomorrow. Was £2.87. youtube.com/watch?v=kADI...

May the 4th be with you. The Minstrel 4th. *3.25/6.5MHz Z80 based computer kit *49K RAM *Jupiter ACE compatible *Forth or ZX81 BASIC *RC2014 expansion slot *40 key keyboard *PAL/NTSC mono composite video *1 bit sound www.tindie.com/products/tyn... (or DM me directly if you don't want to use Tindie)

The FCC's modernisation of satellite spectrum rules alters how GSO and NGSO systems interact, paving the way for a 700% increase in space-based broadband capacity. #fcc #telecoms #5g #edgecomputing #iot #satellites #connectivity #space #technology

A high street magazine cover promising to explain SIN, COS and TAN is glorious, though. ❤️

Day Counter xkcd.com/3228/

So, moving backwards, this kind of incredibly tight display timing isn't new as such, although the current crop of implimentation is certainly special. We've got a David Webb type in, Paul Farrows flicker free zx80 and Andy B's uridium available as a few contemporary examples. All building on ideas.

YouTuber lands on Moon using a ZX Spectrum. Conditions apply

PicoZ80 is a Drop-in Replacement for Everyone’s Favorite Zilog CPU

Nice!

An early Christmas present from Spectaculator www.spectaculator.com/2025/12/spec...

The Jupiter ACE was built by two ex-Sinclair engineers who helped design the ZX Spectrum — the only home micro to run FORTH! The archive preserving its legacy needs support. Help keep this Sinclair heritage alive! 🕹️ https://www.jupiter-ace.co.uk/

My morning: read the post, then read the linked Wikipedia article (en.wikipedia.org/wiki/Sinclai...), then read the linked Incomplete Spectrum ROM Disassembly (web.archive.org/web/20150901... and finally read the linked Online Gosh Wonderful ROM Assembly File (web.archive.org/web/20150826...).

Sinclair 4K BASIC for the ZX80 https://lobste.rs/s/tukeyq ##historical ##retrocomputing

Happy Pi Day!

Quicksort inventor Tony Hoare reaches the base case at 92

20 GOTO 10 Popular Computing Weekly (1985-12-12), page 14 Full mag --> https://archive.org/stream/popular-computing-weekly-1985-12-12#page/n13

The Sinclair ZX80 Manual has all the right characters but not necessarily in the right order. 🙂 CHR$ 228 is “>” CHR$ 229 is “<“

The accompanying photo is interesting as that Spectrum never shipped. Instead the US got the TS2068 in silver with a cartridge port.

Implementing a clear room Z80 / ZX Spectrum emulator with Claude Code: antirez.com/news/160

Go Johnny Go! Viz magazine started in 1979.

You know what goes well with pancakes? Yes! A MicroBeast kit! feersumbeasts.com

I am out there where nobody can hear me scream.

https://archive.org/stream/NH2021_Popular_Computing_Weekly_Issue870212.pdf#page/n03/mode/2up (2/2)

Steve Vickers interviewed about his time at Sinclair, saving ROM space on the ZX81 and the ZX Spectrum and the new venture the Jupiter Ace. youtube.com/watch?v=kgWj...

It is with great sadness that we share the news of the death of Prideaux Fellow David M. Webb MBE (1983, Mathematics), who passed away yesterday. David was a distinguished Exonian whose legacy will not be forgotten. 🔗 Read the Rector's tribute: https://ow.ly/hhMa50XWF52 #ExeterCollegeOxford

Happy New Year! ✨ Looking back at 2025 — a great year at SC: • 25 new updates of ZXDB • 8 major releases of new website features and fixes • 2,200+ videos re-created from the lost RZXArchive YouTube channel 🚀 2026 - looking forward to service the ZX Spectrum community - and related machines 😘

Intel announced the 8087 floating-point chip in 1980. Now I have a blog post that explains a small part of the microcode in this chip. www.righto.com/2025/12/8087...

Did you know that the first instruction in the ZX Spectrum ROM is DI - Disable Interrupts. Quite a dramatic entrance. The DI instruction was not used in the ZX80 and ZX81. Here is my ZX80 assembly listing from 2002. I tried to use the Logan O’Hara labels when apt. web.archive.org/web/20150501...

How to set your ZX Spectrum to 10:00 am. Make it pause for twenty minutes.

The ZX Spectrum has accurate integers using binary logic. After any decimal point, every digit is converted into an inaccurate recurring binary which is then added to the running total. This is fuzzy logic and all the duds average each other out so that half the time the number is correct. #fuzzy

Wow! The source code for the ZX Spectrum has been posted to the Internet Archive by Timex Computer Corp. see my other posts. Right at the end where the 7 byte “ROOT:” routine is Steven has written “***REPLACE WITH NEWTON-RAPHSON SQUARE ROOT***” I used it in the SG03.rom for the ZX81 and now BL81.

Did you know that the Complete ZX Spectrum source code has been uploaded to Internet Archive by Timex. It was written by Nine Tiles on Zilog Development Studio and Timex obtained the same software. A bit dry but there is a FART joke in there. See the last file. archive.org/details/time...

Website Task Flowchart xkcd.com/3175/

Popular Computing Weekly cover (12/12/1985) READ: https://archive.org/stream/NH2021_Popular_Computing_Weekly_Issue851212.pdf#page/n00/mode/2up #zxspectrum #retrogaming

Speccy clone storms back for Christmas without a shred of Sinclair code

“The Spectrum” an iconic modern version of the 1982 classic ZX Spectrum, is now on sale in the UK for £59.99 at Amazon. A bargain and the default square root is my fast and accurate 2003 routine. Twenty games included but in my experience it runs everything.

Ever wanted to know how your ZX81 ranked against a CRAY supercomputer from 1984? Assuming your eyesight is good enough, now you know.

Here's a Sinclair Microdrive cartridge with a UK pound coin for comparison. We trusted these mini-magnetic tape loops with our valuable data in the 1980s. Totally insane! To be fair, they were actually quite reliable. The tape loop is 5 metres long and stores a minimum of 85 to 100KBytes of data.

One of the most difficult BBC Micro books to obtain. Is there anyone out there that has a copy? I managed to get an ex-library copy that was re-bound. Curious to know how many are actually around. It was withdrawn from sale for legal reasons - it contained an annotated disassembly of BBC BASIC.

This is the most exciting ZX81 BASIC program ever. It runs on any Sinclair ZX81 model - TS1000 etc. It compares the upcoming LG81 ROM with the host ZX81 ROM. This BASIC program should be downloadable soon but if you want to see how bad your ZX81 is get typing. Developed on iOS ZX81 by Kevin Palser.

Download The Looking Glass ZX Spectrum ROM V1.08 from spectrumcomputing.co.uk/entry/44586/... speccy4ever.speccy.org/_CMS.htm ZX Spectrum ROMs and games.