Notices by Ed S (eds@mastodon.sdf.org)

#DSCOVR in safe mode at L1, a million miles away... a #spacecraft with a long history. Thanks Al Gore!

"DSCOVR has been designed for a Gyro-Less Safe Mode Attitude Control – relying only on sun sensor readings and information from the reaction wheels. The safehold system uses wheel tachometers to estimate spacecraft body rates about the sun vector in order to achieve a sufficient accuracy in sun-pointing during safe mode periods."

Lots of info:
http://spaceflight101.com/dscovr

#space

@mala

That was deeply #retrocomputing, @SDF !
B language
PDP-7
Unix-50

Here's a thing! It's a forum, for #retrocomputing
There's a weekly digest email and an RSS feed. Sign up today!
https://retrocomputingforum.com/categories
(Boost this for extra points)

#homebrewcomputer is an excellent idea,
@daremo

You'll find a few like-minded people over on the AnyCpu forums.
https://anycpu.org/forum/search.php?search_id=active_topics

And pointers within, I think, to retrobrewcomputers and some projects on hackaday.io

Have a look for a second hand #NC100 - A4-sized notepad with LCD, nice keyboard, serial port, great battery life, built in word processor, calculator, diary - and #BBCBasic complete with built in #Z80 assembler.

Here's a video review:
https://www.youtube.com/watch?v=6h-mzMC-FYM

30-40 hours of battery life, according to the Q&A:
https://www.ncus.org.uk/qanda_hardware.htm

And there's a project to put a CP/M-like OS on it. And #fuzix too, I think.

#retrocomputing

@carbontwelve @bhtooefr

I'm seeing a bunch of wizards in their library with their grimoires, muttering about how people think it's just magic, but really it's lots of study and protocol stacks.

The Wayback machine has a copy of the #Z80000 reference manual

https://web.archive.org/web/20100806073913/http://www.bitsavers.org/pdf/zilog/Z80000_prelimRefMan_Sep1984.pdf

But anyhow I fixed the wikipedia link... bitsavers must have reorganised.

https://en.wikipedia.org/wiki/Zilog_Z80000

Patel's "inside look" paper probably worth a read
https://www.computer.org/csdl/proceedings/afips/1984/5091/00/50910083.pdf

@vertigo @djsundog

"Whose printer can print 132 columns at 500 lines per minute with a MTBF in excess of 3,000 hours for less than $5,500? What one machine can print 1200 lines a minute or plot at three inches per second with dual array density? What plotter uses the world’s most powerful electrostatic plotting software?

Versatec has it all. More models. Better print and plot quality. The best price/performance ratio in the industry.

Fan-fold paper output stacks neatly and automatically in basket."

@bhtooefr

There's a forum for the MyStorm FPGA dev board - it's £42, it's open source hardware and software, and it has a nice big fast SRAM.

https://forum.mystorm.uk/t/more-blackice-boards-now-available-in-time-for-christmas/318/1

@wxcafe @djsundog

#compymakers is a lonely hashtag, but I'd like to join the party!

Can I interest anyone in a novel CPU, available in 16 or 32 bits, a pleasure to program and capable of being a BCPL target? It's a one-page-computer, where each source file fits on a single page of green bar fanfold.
https://hackaday.io/project/25617-opc-5-a-cpu-for-fpga-in-one-page

It's not mine, but I'm on the team...

@djsundog @jk

Can I recommend a quick study of the PiTubeDirect project? It's a bare-metal ARM project which uses the Raspberry Pi's VideoCore CPU to bitbang responses to a 2MHz 6502 bus, so it can emulate a number of second processor architectures from a Zero plugged discreetly into a BBC micro.

Whereby we get a fast 6502, Z80, x86, 6809 and superfast ARM attachments for our 1980's computing device. Oh, and a 32-bit NS32k too, to run Fortran benchmarks.

@djsundog

It seems WASH, the CP/M file manager, dates from 1981. See this timeline:
http://www.xtreefanpage.org/x23chron.htm

@vertigo @Ricardus @djsundog

Speaking of trying out all the emulators, I'm a bit of a fan of those which run in the browser. Full-screen the browser and you get the feeling of just having the machine to yourself. There's a hundred or so catalogued here, from the usual 8bit suspects, to early Unix capable machines, even earlier machines, 16 bit machines - you name it!

https://github.com/fcambus/jsemu#emulators-written-in-javascript

#acorn #atari #commodore #altair #amstrad #datageneral #apple #dec #robotron #sinclair #tandy #ibmpc #babbage

@fluffy @ajroach42

Maybe most interesting is Acorn's BBC Micro - it's a reasonable 8bit machine as is, but architected to act as a front-end to a bigger faster "second processor" - from Z80 to x86, and the very first ARM product.

These days, you can plug a Raspberry Pi into the bottom of your Beeb, and it can emulate a few second processors: a 274MHz 6502, a 100MHz Z80, a 6809, an x86, an ns32k, an ARM.

Then run GEM, or PanOS, or CP/M, and write in Pascal, Fortran, Lisp, C.

@shoutcacophony @ajroach42

Can I recommend RISC OS Pico? It's a tiny RISC OS for your Raspberry Pi, boots instantly to BBC Basic (black screen, white text) but there are plenty of commands to do old-school graphics in a number of old, and new, screen resolutions. And of course the Basic has an ARM assembler built in!

(This is a single-tasking and GUI-free version of RISC OS. Surely a good one for #retronauts)

@bhtooefr @ajroach42

I invite you to search [fowler ternary] for a surprising history.

Or have a play in your browser at
http://www.edmundgriffiths.com/setunka.html

#ternary #ternarycomputing
#setun

@djsundog

Dance as if no-one's listening.

https://www.youtube.com/watch?v=_6FBfAQ-NDE
(Depeche Mode - Just Can't Get Enough)

@djsundog

There's a nice piece about #z80 behaviour, and some good links, in this article about emulator fidelity:
https://floooh.github.io/2017/12/10/z80-emu-evolution.html

It turns out that you sometimes need cycle-by-cycle fidelity which is much harder than instruction by instruction.

The RetroBrewComputers forum is good for z80 and 68k and other systems:
https://retrobrewcomputers.org/forum/

@vertigo @solderpunk @vfrmedia

You can get started with easy6502 - from zero to snake in one big page.

http://skilldrick.github.io/easy6502/

And then you work up to visual6502!

http://visual6502.org/JSSim/expert.html?graphics=false&steps=50

Or is that working your way down?

@solderpunk

On the landing of double-buffering: "GNU #Emacs is an old-school C program #emulating a 1980s #Symbolics Lisp Machine emulating an old-fashioned Motif-style Xt toolkit emulating a 1970s text terminal emulating a 1960s teletype. Compiling Emacs is a challenge. Adding modern rendering features to the redisplay engine is a miracle."

Source: a facebook post so I won't link it. Ha! But I will link the excellent LWN:
https://lwn.net/Articles/705234/

via
@gutigen
via @PinkCathodeCat