This worked better than I expected. The tricky parts are trimming the edges and getting it them straight.
Here’s the image to print on your label maker:
Category: computers suck
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p-touch Pico pin labels
Pico pin labels: not bad for a first try print on 12.7 mm tape -
Raspberry Pi Zero 2 W: slides and thermals
Slides from last night’s talk:
It’s impossible to have a Raspberry Pi Zero overheat unless you overclock it. That’s why you don’t get any cases for it with fans or heat sinks. The quad-core Raspberry Pi Zero 2 W, though, has the potential to do so. Here are some numbers:
- Used official case with lid fitted: increases SoC temperature +3 °C over free air
- Test – CPUBurn: https://github.com/pmylund/cpuburn
- Tested 4, 3 and 2 cores burning in 32-bit and 64-bit modes: time from idle to throttling (80 °C) measured
- GPU overheat not tested.
All 4 cores burning, 64-bit mode: time to overheat = under 3½ minutes 
All 4 cores burning, 32-bit mode: time to overheat = just over 4 minutes 
3 out of 4 cores burning, 64-bit mode: time to overheat = just over 7 minutes 
3 out of 4 cores burning, 32-bit mode: time to overheat = 9½ minutes 
2 out of 4 cores burning, 32-bit mode: time to overheat = basically never Unless you’re doing things that might indicate you should be using a bigger computer, a Raspberry Pi Zero 2 W won’t overheat and doesn’t need any form of cooling. If you’re overclocking, well … it’s your choice to have cooling equipment worth more than the computer it’s trying to cool.
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Raspberry Pi Zero 2 W: initial performance
Running A Pi Pie Chart turned out some useful performance numbers. It’s almost, but not quite, a Raspberry Pi 3B in a Raspberry Pi Zero form factor.
32-bit mode
Running stock Raspberry Pi OS with desktop, compiled with stock options:
multi-thread results 
single-thread results time ./pichart-openmp -t "Zero 2W, OpenMP" pichart -- Raspberry Pi Performance OPENMP version 36 Prime Sieve P=14630843 Workers=4 Sec=2.18676 Mops=427.266 Merge Sort N=16777216 Workers=8 Sec=1.9341 Mops=208.186 Fourier Transform N=4194304 Workers=8 Sec=3.10982 Mflops=148.36 Lorenz 96 N=32768 K=16384 Workers=4 Sec=4.56845 Mflops=705.102 The Zero 2W, OpenMP has Raspberry Pi ratio=8.72113 Making pie charts...done. real 8m20.245s user 15m27.197s sys 0m3.752s ----------------------------- time ./pichart-serial -t "Zero 2W, Serial" pichart -- Raspberry Pi Performance Serial version 36 Prime Sieve P=14630843 Workers=1 Sec=8.77047 Mops=106.531 Merge Sort N=16777216 Workers=2 Sec=7.02049 Mops=57.354 Fourier Transform N=4194304 Workers=2 Sec=8.58785 Mflops=53.724 Lorenz 96 N=32768 K=16384 Workers=1 Sec=17.1408 Mflops=187.927 The Zero 2W, Serial has Raspberry Pi ratio=2.48852 Making pie charts...done. real 7m50.524s user 7m48.854s sys 0m1.370s
64-bit
Running stock/beta 64-bit Raspberry Pi OS with desktop. Curiously, these ran out of memory (at least, in oom-kill‘s opinion) with the desktop running, so I had to run from console. This also meant it was harder to capture the program run times.
The firmware required to run in this mode should be in the official distribution by now.
multi-thread, 64 bit: no, I can’t explain why Lorenz is better than a 3B+ 
single thread, again with the bump in Lorenz performance pichart -- Raspberry Pi Performance OPENMP version 36 Prime Sieve P=14630843 Workers=4 Sec=1.78173 Mops=524.395 Merge Sort N=16777216 Workers=8 Sec=1.83854 Mops=219.007 Fourier Transform N=4194304 Workers=4 Sec=2.83797 Mflops=162.572 Lorenz 96 N=32768 K=16384 Workers=4 Sec=2.66808 Mflops=1207.32 The Zero2W-64bit has Raspberry Pi ratio=10.8802 Making pie charts...done. ------------------------- pichart -- Raspberry Pi Performance Serial version 36 Prime Sieve P=14630843 Workers=1 Sec=7.06226 Mops=132.299 Merge Sort N=16777216 Workers=2 Sec=6.75762 Mops=59.5851 Fourier Transform N=4194304 Workers=2 Sec=7.73993 Mflops=59.6095 Lorenz 96 N=32768 K=16384 Workers=1 Sec=9.00538 Mflops=357.7 The Zero2W-64bit has Raspberry Pi ratio=3.19724 Making pie charts...done.
The main reason for the Raspberry Pi Zero 2 W appearing slower than the 3B and 3B+ is likely that it uses LPDDR2 memory instead of LPDDR3. 64-bit mode provides is a useful performance increase, offset by increased memory use. I found desktop apps to be almost unusably swappy in 64-bit mode, but there might be some tweaking I can do to avoid this.
Unlike the single core Raspberry Pi Zero, the Raspberry Pi Zero 2 W can be made to go into thermal throttling if you’re really, really determined. Like “3 or more cores running flat-out“-determined. In my testing, two cores at 100% (as you might get in emulation) won’t put it into thermal throttling, even in the snug official case closed up tight. More on this later.
(And a great big raspberry blown at Make, who leaked the Raspberry Pi Zero 2 W release a couple of days ago. Not classy.)
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Another Raspberry Pi Pico language: MMBasic
It’s very much a work in progress, but Geoff Graham and Peter Mather’s MMBasic runs nicely on the Raspberry Pi Pico. Development is mostly coordinated on TheBackShed.com forum.
- Download and manual: Geoff’s Projects – BASIC Interpreter for the Raspberry Pi Pico
- Source: MMBasic running on the Raspberry Pi Pico
It supports an impressive range of displays and peripherals. The project gives me a very distinct “This is how we do things” vibe, and it’s quite unlike any other Raspberry Pi Pico project.
To show you what MMBasic code looks like, here’s a little demo that uses one of those “Open Smart” LED traffic lights on physical pins 14-16 which cycles through the phases every few seconds:
' traffic light on gp10-12 (green, yellow, red), pins 14-16 ' set up ports for output FOR i=14 TO 16 SETPIN i, DOUT PIN(i)=0 NEXT i red=16 amber=15 green=14 DO ' green on for 5 seconds PIN(red)=0 PIN(green)=1 PAUSE 5000 ' amber on for 3 seconds PIN(green)=0 PIN(amber)=1 PAUSE 3000 ' red on for 5 seconds PIN(amber)=0 PIN(red)=1 PAUSE 5000 LOOP
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gecko at the watering hole, forever
- Video downloaded using youtube-dl
- Resized to 360p and 30 fps using ffmpeg
- Loop found and resized using MoviePy, with ffmpeg used to create the gif
- gif optimized using gifsicle -O3
Result: 320×180, 22 frames, 128 colours, ~ 600 KB.
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Some okay CMYK results from DrawingBot, finally …
drawn using a Roland DXY-1300 plotter on Strathmore Multimedia using DeSerres medium tip pens, ~60 minutes plotting time, 180 × 180 mm After a tonne of faffing about, I finally got something out of my plotter using Drawing Bot. I’d heard about it during the Bold Machines’ Intro to Pen Plotters course I’m taking, and the results that other people were getting looked encouraging. But for me, they weren’t great.
Maybe I was choosing too large images, but my main problem was ending up with plots with far too many lines: these would take days to plot. The controls on Drawing Bot also seemed limited: density and resolution seemed to be the only controls that do much. Drawing Bot itself wasn’t very reliable: it would sometimes go into “use all the cores!” mode when it was supposed to be idling. It would also sometimes zoom in on part of the image and fail to unzoom without quitting. Is a 32 GB i7 8-core (oldish, but still game) too little for this software? Forget any of the Voronoi plots if you want to see results today.
The source image was a geometric tile that I’d frisketed out years ago, forgotten about, and then found when I unstuck it from under a stack of papers. It’s somewhat artisanally coloured by me in watercolour, and the mistakes and huge water drop are all part of its charm:
source image for plotter output If WordPress will allow an SVG, here’s what Drawing Bot made of it:
Drawing Bot SVG output: yes, it’s that faint I do like the way that Drawing Bot seems to have ignored some colours, like the rose pink around the outside. The green border really is mostly cyan with a touch of black.
I haven’t magically found perfect CMYK pens in HP/Roland pen format. I couldn’t even find the Schwan-Stabilo Point 88 pens that Lauren Gardner at Bold Machines recommends. But the local DeSerres did deliver a selection of their own-brand 1.0mm Mateo Markers that are physically close to the Point 88s in size, but use a wider 1 mm fibre tip. They are also cheap; did I mention that?
The colours I chose were:
- for cyan: Mint Green; RGB colour: #52C3A5; SKU: DFM-53
- for magenta: Neon Pink; RGB colour: #FF26AB; SKU: DFM-F23
- for yellow: Neon Yellow; RGB colour: #F3DE00; SKU: DFM-F01
- for black: Green Grey 5; RGB colour: #849294; SKU: DFM-80
The RGB colours are from DeSerres’ website, and show that I’m not wildly off. Target process colours are the top row versus nominal pen colours on the bottom:
yes, there are fluo colours in there I knew to avoid pure black, as it would overpower everything in the plot.
To make the pens work with the DXY-1300, I modified juliendorra/3D-printable-plotter-adapters-for-pens-and-refills: Use your favorite pens with vintage HP plotters: parametric code to create custom adapters to work the the DeSerres pens. Here are my changed files, just in case my PR isn’t accepted:
Overall, it plotted quite well. I plotted directly from Inkscape, one layer/pen at a time, from light (yellow) to dark (grey). Using the pen 1 slot had its disadvantages: the DXY has little pen boots to stop the pens drying, but these unfortunately get filled with old ink. The scribbly dark markings in the NNE and SSW orange kites in the plot are from the yellow pen picking up old black ink from the pen boot. Next time I’ll clean the plotter better.
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for Paul Carter, after 15 years
All the Colours We Have (for Paul Carter) — 2021 re-encoding It’s hard to believe that Paul Carter has been gone fifteen years. Like all things digital, my ten year memorial for him was a bit dusty, so I did a re-encoding that will look better on today’s devices. The info page is unchanged.
Still miss you, buddy. It gets further but no easier.
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detail from a million step random walk
each line can be drawn at 0°, 60°, 120°, …, 300° and can be coloured red, orange, yellow, green, cyan or purple depending on direction. White areas are unfilled sections of the background This is a tiny detail from an unfeasibly large random walk made in Berkeley Logo. The code looks something like this:
; random dice walk, with colours for each of six directions ; scruss, 2021-07 make "ch {14 6 2 3 13 4} make "dirs {0 60 120 180 240 300} make "sides {1 2 3 4 5 6} to walk make "throw pick sides setheading item :throw dirs setpencolor item :throw ch forward 20 end hideturtle repeat 1000 [walk] -
Tetris for Applesoft BASIC
a very paused game Paleotronic’s Tetris for Applesoft BASIC is a surprisingly decent version for something that’s written in an interpreted language. It’s not what anyone would call zippy, but it’s not so slow that you want to give up.
Paleotronic want you to type it in, but life’s too short for that. You can play it in your browser on the Internet Archive: Tetris for Applesoft BASIC by Mark Stock
Or download an auto-booting Apple II disk image:
Keys:
- , — move left
- . — move right
- A — rotate left
- R — rotate right
- Z — drop
- P — pause
- Q — quit
Life’s also too short for correcting OCR errors in BASIC code. Tesseract is hilariously bad at recognizing source code, so I had to go through this several times. AppleCommander’s BASIC Tools was very handy for catching the last of the errors with its variable dump: caught the cases of the TO keyword converted to the variable T0 … and frankly, I am no fan of SmartQuotes when applied to source code, either.
Here’s the source, straight from the interpreter with all its weird spacing:
10 GOSUB 1000 100 W = W +1: IF W >LV THEN W = 0: GOSUB 350 110 K = PEEK(KB): IF K > = H THEN POKE KC,H:K = K -H: GOSUB 300 190 GOTO 100 200 PY = PY *A2: VLIN PY,PY +A1 AT PX: RETURN 225 PY = PY *A2: HLIN X1,X2 AT PY: HLIN X1,X2 AT PY +A1: RETURN 300 ON E(K) GOTO 30000,330,340,350,360,30100 310 RETURN 330 X = X -1: GOTO 400 340 X = X +1: GOTO 400 350 DN = 1:Y = Y +1: GOSUB 400:DN = 0: RETURN 360 S = S +1: IF S/4 = INT(S/4) THEN S = S -4 400 GOSUB 500 410 GOSUB 800: IF F = 0 THEN X = XX:Y = YY:S = SS: GOSUB 420: IF DN THEN GOSUB 900 420 COLOR= CF: FOR PP = 1 TO 4:PX = X +X(S,PP):PY = Y +Y(S,PP): GOSUB 200: NEXT PP:XX = X:YY = Y:SS = S:D = 0: RETURN 500 IF DD THEN RETURN 510 COLOR= CB: FOR PP = 1 TO 4:PX = XX +X(SS,PP):PY = YY +Y(SS,PP): GOSUB 200: NEXT PP:DD = 0: RETURN 800 F = 1: FOR PP = 1 TO 4:PY = Y +Y(SS,PP): ON ( FN PC(X +X(S,PP)) >0) GOTO 805: NEXT PP: RETURN 805 F = 0: RETURN 850 F = 1: RETURN 900 P = 10: GOSUB 30300 905 RN = 0:Y = YM 910 X = XL 920 PY = Y: IF FN PC(X) = CB THEN 950 930 X = X +1: IF X < = XR THEN 920 940 R(RN) = Y:RN = RN +1 950 Y = Y -1: IF Y > = 0 THEN 910 960 IF RN THEN GOSUB 30400 970 Y = 0 980 X = INT((XR -XL)/2) +XL 985 S = INT( RND(1) *NS):CF = C(S):S = S *4 990 GOSUB 800: IF F THEN RETURN 995 GOTO 31000 1000 DIM E(127),X(27,4),Y(27,4),R(40) 1010 TEXT : HOME : GR 1011 PRINT "WELCOME..." 1014 LM = 10 1015 XM = 10:YM = 15 1016 XL = INT((40 -XM)/2) 1017 XR = XL +XM -1 1021 A1 = 1 1022 A2 = 2 1030 DEF FN PC(X) = SCRN( X,PY *A2) 1040 CB = 0 1050 XX = 20:YY = 0:SS = 0 1100 KB = -16384 1110 KC = -16368 1120 H = 128 1129 REM KEYBOARD ACTIONS 1130 REM QUIT 1131 E( ASC("Q")) = 1 1132 E( ASC("Q") -64) = 1 1140 REM MOVE LEFT 1141 E(8) = 2 1142 E( ASC(",")) = 2 1150 REM MOVE RIGHT 1151 E(21) = 3 1152 E( ASC(".")) = 3 1160 REM MOVE DOWN 1161 E(32) = 4 1162 E( ASC("Z")) = 4 1170 REM ROTATE 1171 E( ASC("R")) = 5 1172 E(13) = 5 1173 E( ASC("A")) = 5 1179 REM PAUSE GAME 1180 E( ASC("P")) = 6 1181 E( ASC("P") -64) = 6 1185 GOSUB 2000 1186 GOSUB 1300 1190 PRINT "PRESS ANY KEY TO START..." 1191 PRINT 1192 PRINT "PRESS Q TO QUIT." 1193 GOTO 31020 1299 REM DRAW THE GAME 1300 COLOR= 4: FOR I = 0 TO 19:X1 = 0:X2 = 39:PY = I: GOSUB 225: NEXT 1320 COLOR= CB: FOR I = 0 TO YM:X1 = XL:X2 = XR:PY = I: GOSUB 225: NEXT 1350 RETURN 1400 DATA 1 1401 DATA 0,0,1,0,0,1,1,1 1402 DATA 0,0,1,0,0,1,1,1 1403 DATA 0,0,1,0,0,1,1,1 1404 DATA 0,0,1,0,0,1,1,1 1410 DATA 2 1411 DATA 0,1,1,1,2,1,3,1 1412 DATA 1,0,1,1,1,2,1,3 1413 DATA 0,1,1,1,2,1,3,1 1414 DATA 1,0,1,1,1,2,1,3 1420 DATA 12 1421 DATA 1,1,0,1,1,0,2,1 1422 DATA 1,1,0,1,1,0,1,2 1423 DATA 1,1,0,1,2,1,1,2 1424 DATA 1,1,1,0,2,1,1,2 1430 DATA 13 1431 DATA 1,1,0,1,2,1,0,2 1432 DATA 1,1,1,0,1,2,2,2 1433 DATA 1,1,0,1,2,1,2,0 1434 DATA 1,1,1,0,1,2,0,0 1440 DATA 9 1441 DATA 1,1,0,1,2,1,2,2 1442 DATA 1,1,1,0,1,2,2,0 1443 DATA 1,1,0,1,2,1,0,0 1444 DATA 1,1,1,0,1,2,0,2 1450 DATA 3 1451 DATA 1,1,1,0,0,0,2,1 1452 DATA 1,1,1,0,0,1,0,2 1453 DATA 1,1,1,0,0,0,2,1 1454 DATA 1,1,1,0,0,1,0,2 1460 DATA 6 1461 DATA 1,1,0,1,1,0,2,0 1462 DATA 1,1,0,1,0,0,1,2 1463 DATA 1,1,0,1,1,0,2,0 1464 DATA 1,1,0,1,0,0,1,2 1990 DATA -1 2000 X = 0:Y = 0 2010 NS = 0 2020 READ C: IF C < > -1 THEN C(NS) = C: FOR J = 0 TO 3: FOR I = 1 TO 4: READ X(NS *4 +J,I): READ Y(NS *4 +J,I): NEXT I: NEXT J:NS = NS +1: GOTO 2020 2030 RETURN 21210 P = 1: RETURN 30000 TEXT : HOME : END 30100 HOME 30110 PRINT "GAME PAUSED. PRESS P TO CONTINUE..." 30120 P = 1 30130 K = PEEK(KB): IF K > = H THEN POKE KC,H:K = K -H: GOSUB 30200 30140 IF P THEN 30130 30150 HOME 30160 PRINT "SCORE ";SC; TAB( 21);"LEVEL ";LM -LV +1 30170 RETURN 30200 ON E(K) GOTO 30000,30210,30210,30210,30210,30220 30210 RETURN 30220 P = 0 30230 RETURN 30300 SC = SC +P 30310 VTAB 21: HTAB 7 30320 PRINT SC; 30330 RETURN 30400 RN = RN -1 30410 FOR C = 0 TO 32 30415 COLOR= C 30420 FOR I = 0 TO RN:X1 = XL:X2 = XR:PY = R(I): GOSUB 225: NEXT I 30430 FOR I = 0 TO 2: NEXT I 30440 NEXT C 30450 FOR I = 0 TO RN 30460 Y = R(I) +I 30470 YP = Y -1: FOR X = XL TO XR:PY = YP: COLOR= FN PC(X):PX = X:PY = Y: GOSUB 200: NEXT X:Y = Y -1: IF Y >0 THEN 30470 30480 P = 100: GOSUB 30300 30490 NEXT I 30495 RETURN 31000 VTAB 22: PRINT 31010 PRINT " GAME OVER" 31020 P = 1 31030 K = PEEK(KB): IF K > = H THEN POKE KC,H:K = K -H: GOSUB 31200 31040 IF P THEN 31030 31050 D = 1 31060 SC = 0:LV = LM 31070 GOSUB 30150 31080 GOSUB 1300 31090 GOTO 905 31200 ON E(K) GOTO 30000 31210 P = 0: RETURN 32000 REM END OF LISTINGIf only AppleSoft had a RENUM command, the code might not look so messy
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digging the BlueSCSI
I like old (as in 68K old) Apple Macintoshes, but I don’t like their hard drives. Apple used SCSI drives, which were super-cool at the time (multiple drives on one bus! extra devices like SCSI scanners, too!) but now seem an absolute pain. There may be a lot to complain about with USB storage, but compared to SCSI, it just works.
While the 40 MB Quantum SCSI drive in my Mac Classic II still works, it gets really full really fast and that old spinning rust won’t spin forever. One of the newer ways to replace a SCSI drive is the BlueSCSI, an open-everything design based on a cheap Blue Pill micro-controller board, a Micro-SD card slot and some passive components. The whole kit is very affordable, and a local maker sells them, so it was worth a try.
I’ve had nothing but miserable failure with Blue Pill boards, and very quickly moved on to STM32F4 board that actually work. It didn’t fill me with much hope that the board I got with my kit looked like this, end on:
There are two USB connectors on this board.
There are two of ____.Despite that oddness, it all soldered up fine (the surface-mount card slot was a little fiddly) and it fits inside the Classic II’s cavernously empty shell wherever I choose to stick it down.
I thought I knew what I was doing in making filesystem images (hence my recent nonsense anent HFS utilities), but clearly I was wrong. The 2 GB images I made in Basilisk II weren’t recognized at all. For now, I’m booting from one of the RaSCSI canned boot images plus a couple of the blank formatted drive images to put my own custom system on.
I’m trying to get as much as possible set up on the Micro-SD card while I can still access it, as the Classic II’s case is not something you can pop open on a whim. It needs a special long-thin Torx T15 driver to even get the case partially open, then you have to ease/fight the case the rest of the way. Aside from the faint ponk of dodgy analogue board caps (I’ll fix ’em one day, I promise!), you have to remember to tiptoe around the life-ending voltages lurking at the back of the CRT when you’re working there. Retrotechnology: it smells bad and it can kill you!
A feature I really appreciate with the BlueSCSI is that it dumps a status log on the card every time it boots. It took me a while to get the hang of naming images correctly, but I’d have been absolutely lost without logs with this level of detail:
BlueSCSI <-> SD - https://github.com/erichelgeson/BlueSCSI VERSION: 1.0-20210410 DEBUG:0 SCSI_SELECT:0 SDFAT_FILE_TYPE:3 SdFat version: 2.0.6 SdFat Max FileName Length: 32 Initialized SD Card - lets go! Not an image: LOG.txt Imagefile: HD10_512 753.hda / 41943040bytes / 40960KiB / 40MiB Imagefile: HD20_512 BS.hda / 41943040bytes / 40960KiB / 40MiB Imagefile: HD40 MacHD-1000MB.hda / 1048576000bytes / 1024000KiB / 1000MiB Imagefile: HD30_512 MacHD-500MB.hda / 524288000bytes / 512000KiB / 500MiB ID:LUN0:LUN1: 0:----:----: 1: 512:----: 2: 512:----: 3: 512:----: 4: 512:----: 5:----:----: 6:----:----: Finished initialization of SCSI Devices - Entering main loop.
So I’ve got four SCSI drives pretending to live on this card, and even if one of them’s not quite named correctly (HD40 MacHD-1000MB.hda should be called HD40_512 MacHD-1000MB.hda), it’s been found okay.
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Powering a Cambridge Z88 with a MT3068 module
my Z88 – USB power cable, with slightly stoory Z88 underneath I got a Cambridge Computer Z88 again, after perhaps 30 years of not having one. They are very nice little portable computers, remarkable for packing a multi-tasking OS into an 8-bit machine that runs for weeks on 4x AA batteries.
But the Z88 is a Clive Sinclair joint, so there’s going to be at least one deeply weird and/or ill-advised detail about it. For me, it’s the power adapter. The original had a 6 V centre-positive barrel connector, but in true Sinclair fashion, that wasn’t quite ideal.
The DC power comes through a diode, which drops it down to ~5.2 V. The batteries supply up to 6 V and there’s no protection circuit, so the DC adapter won’t do anything until the internal batteries discharge down to that level. This is far from ideal.
The clever way of dealing with this was Rakewell’s Z88 PSU. This was a variable voltage PSU set to deliver 7 V, so that even when dropped through the power diode, it wouldn’t deplete the batteries.
Unfortunately, Rakewell stopped selling these a while ago. But I remembered I had a some MT3608 (datasheet) boards bought at a hamfest some years back. MT3608s are boost DC-DC converters, so they’ll convert from a lower DC voltage to a higher one, typically at least +2 V higher than the input. With a hacked-up USB cable, a small length of DC cable with a connector and a 3d printed case, I built one that works quite well, at least in the short time I’ve tested it.
- I used the MT3608 step up DC boost box design from Thingiverse
- Newer MT3608 boards sometimes feature a micro-USB connector, which is much more convenient than hacking up a USB cable
- It’s really important to know how to adjust a MT3608 DC-DC Booster before connecting the final voltage, as it’s very easy to burn the board out
- You can’t use a computer USB port to power an MT3608, as the cable’s not smart enough to negotiate a decent amount of current. A good phone charger should be enough.
- I set the voltage output to be 7.05 V, with no load
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niche 68K Mac emulation needs
“It amazes me how you manage to live in anything that small“: actual size Mac Classic II screenshot So I’m refurbishing the Mac Classic II I got in 2016 now that I’ve found that BlueSCSI is a fairly cheap way of providing large replacement storage. The 40 MB (yes, 40 MB) drive from 1992 can finally be replaced.
Hit a snag, though: DiskCopy won’t copy a disk with errors, which this drive seemed to have. DiskCopy also won’t repair the boot disk, so you have to find a bootable floppy or some other way to work around this limitation. The only readily available bootable disk image I could find was the System 7.1 Disk Tools floppy — which reported no errors on my drive! Later versions of Disk First Aid would fix it, but weren’t provided on a bootable image.
Here’s the 7.1 Disk Tools floppy with all of the apps replaced by Disk First Aid 7.2. Both of these were found on the Internet Archive’s download.info.apple.com mirror and combined:
Disk duly repaired, DiskCopy was happy, backup complete. Eventually: the Classic II is not a fast machine at all.
I love the old Mac icons, how they packed so much into so few pixels:
Disk First Aid icon It’s a stylized ambulance with flashing light and driver, the side is a floppy disk, it’s got motion lines and the whole icon is slanted to indicate speed/rush. Nice!
Vaguely related: most old Mac software is stored as Stuffit! archives. These don’t really work too well on other systems, as they use a compression scheme all their own and are specialized to handle the forked filesystem that old Macs use. Most emulators won’t know what to do with them unless you jump through hoops in the transfer stage.
Fortunately, the ancient Linux package hfsutils knows the ways of these hoops, if only you tell it when to jump. The script below takes a Stuffit! file as its sole argument, and creates a slightly larger HFS image containing the archive, with all the attributes set for Stuffit! Expander or what-have-you to unpack it.
#!/bin/bash # sitdsk - make an HFS image containing a properly typed sit file # requires hfsutils # scruss, 2021-07 if [ $# -ne 1 ] then echo Usage: $0 file.sit exit 1 fi base="${1%.sit}" # hformat won't touch anything smaller than 800 KB, # so min image size will be 800 * 1.25 = 1000 KB size=$(du -k "$1" | awk '{print ($1 >= 800)?$1:800}') dsk="${base}.dsk" dd status=none of="$dsk" if=/dev/zero bs=1K count=$((size * 125 / 100)) hformat -l "$base" "$dsk" # note that hformat does an implicit 'hmount' hcopy "$1" ':' # and hcopy silently changes underscores to spaces hattrib -t 'SIT!' -c 'SITx' ":$(echo ${1} | tr '_' ' ')" hls -l humountWhat this does:
- creates a blank image file roughly 25% larger than the archive (or 1000 KB, whichever is the larger) using dd;
- ‘formats’ the image file with an HFS filesystem using hformat;
- copies the archive to the image using hcopy;
- attempts to set the file type and creator using hattrib;
- lists the archive contents using hls;
- disconnects/unmounts the image from the hfsutils system using humount.
Notice I said it “attempts” to set the file type. hfsutils does some file renaming on the fly, and all I know about is that it changes underscores to spaces. So if there are other changes made by hfsutils, this step may fail. The package also gets really confused by images smaller than 800 KB, so small archives are rounded up in size to keep hformat happy.
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Colourful Alligator Clips
Colourful Alligator Clips from Lee Cyborg Everything looks like buds when you have a bud vase.
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CardKB mini keyboard with MicroPython
it really is the size of a credit card
(running with a SeeedStudio Wio Terminal)I got one of these CardKB Mini Keyboards to see if I could use it for small interactives with MicroPython devices. It’s very small, and objectively not great as a mass data entry tool. “Better than a Pocket C.H.I.P. keyboard” is how I’d describe the feel. It’s also pretty reliable.
It’s got an I²C Grove connector, and its brains are an ATMega chip just like an Arduino. It’s strictly an ASCII keyboard: that is, it sends the 8-bit ASCII code of the key combination you pressed. It doesn’t send scan codes like a PC keyboard. The driver source is in the CardKB m5-docs, so if you really felt ambitious you could write a scan code-like firmware for yourself.
The device appears at I²C peripheral address 95, and returns a single byte when polled. That byte’s either 0 if no key was pressed, or the character code of what was pressed. The Esc key returns chr(27), and Enter returns CR. If you poll the keyboard too fast it seems to lose the plot a little, so a tiny delay seems to help
Here’s a small demo for MicroPython that acts as the world’s worst typewriter:
# M5Stack CardKB tiny keyboard - scruss, 2021-06 # MicroPython - Raspberry Pi Pico from machine import Pin, I2C from time import sleep_ms i2c = I2C(1, scl=Pin(7), sda=Pin(6)) cardkb = i2c.scan()[0] # should return 95 if cardkb != 95: print("!!! Check I2C config: " + str(i2c)) print("!!! CardKB not found. I2C device", cardkb, "found instead.") exit(1) ESC = chr(27) NUL = '\x00' CR = "\r" LF = "\n" c = '' print("*** APPALLING TYPEWRITER ***") print("** Type stuff, Esc to end **") while (c != ESC): # returns NUL char if no character read c = i2c.readfrom(cardkb, 1).decode() if c == CR: # convert CR return key to LF c = LF if c != NUL or c != ESC: print(c, end='') sleep_ms(5)And here’s the CircuitPython version. It has annoying tiny differences. It won’t let me use the I²C Grove connector on the Wio Terminal for some reason, but it does work much the same:
# M5Stack CardKB tiny keyboard - scruss, 2021-06 # CircuitPython - SeeedStudio Wio Terminal # NB: can't use Grove connector under CPY because CPY import time import board import busio i2c = busio.I2C(board.SCL, board.SDA) while not i2c.try_lock(): pass cardkb = i2c.scan()[0] # should return 95 if cardkb != 95: print("!!! Check I2C config: " + str(i2c)) print("!!! CardKB not found. I2C device", cardkb, "found instead.") exit(1) ESC = chr(27) NUL = '\x00' CR = "\r" LF = "\n" c = '' b = bytearray(1) # can't really clear screen, so this will do for i in range(12): print() print("*** APPALLING TYPEWRITER ***") print("** Type stuff, Esc to end **") for i in range(8): print() while (c != ESC): # returns NUL char if no character read i2c.readfrom_into(cardkb, b) c = b.decode() if c == CR: # convert CR return key to LF c = LF if c != NUL or c != ESC: print(c, end='') time.sleep(0.005) # be nice, clean up i2c.unlock() -
An hour of Pink Noise
cover made by netpbm, of course an hour of soothing 2-channel noise Direct download: 01-pink_noise.mp3
There are a million variations on the simple “use sox to play masking pink noise“, such as:
play -n synth pinknoise gain -3
This will play synthesized pink noise until you hit Ctrl-C.
But it you want two independent noise channels rather than mono, that’s a little more complex. It’s probably easier to download/play the MP3 file above than show you the command line.
Note that MP3s really aren’t designed to encode such random data, and it’s likely that your player will cause the audio to clip in a couple of places. I’m not quite sure why it does this, but it does it repeatably.
If you want to create this for yourself (and create a bonus lossless FLAC, which was far too large to upload here), here’s what I did to make this:
#!/bin/bash duration='60:00' fade='1' outfile='pinknoise.wav' # make the track sox --combine merge "|sox --norm=-3 -c 1 -b 16 -r 44100 -n -p synth $duration pinknoise" "|sox --norm=-3 -c 1 -b 16 -r 44100 -n -p synth $duration pinknoise" -c 2 -b 16 -r 44100 $outfile fade $fade fade 0 $duration $fade gain -n -3 # make the cover # 1 - text - 500 x 500 px pnmcat -white -tb <(pbmmake -white 500 114) <(pbmtextps -font HelveticaBold -fontsize 64 -resolution 180 "PINK" | pnmcrop) <(pbmmake -white 32 32) <(pbmtextps -font HelveticaBold -fontsize 64 -resolution 180 "NOISE" | pnmcrop) <(pbmmake -white 500 114) > cover-text.pbm # 2 - make the noise bg pgmnoise 500 500 > cover-noise.pgm # 3 - make the magenta text ppmchange black magenta cover-text.pbm > cover-text-magenta.ppm # 4 - overlay with transparency pnmcomp -alpha=<(pnminvert cover-text.pbm | pbmtopgm 35 35 ) cover-text-magenta.ppm cover-noise.pgm | cjpeg -qual 50 -opt -baseline -dct float > cover.jpg # delete the temporary image files, leaving cover.jpg rm -f cover-text.pbm cover-noise.pgm cover-text-magenta.ppm # make the mp3 lame -V 2 --noreplaygain -m s --tt 'Pink Noise' --ta 'Pink Noise' --tl 'Pink Noise' --ty $(date +%Y) --tc "scruss, 2021-05" --tn 1/1 --tg Ambient --ti cover.jpg "$outfile" 01-pink_noise.mp3 # make the flac (and delete wav file) flac --best --output-name=01-pink_noise.flac --delete-input-file --picture=cover.jpg --tag="TITLE=Pink Noise" --tag="ARTIST=Pink Noise" --tag="ALBUM=Pink Noise" --tag="DATE=$(date +%Y)" --tag="COMMENT=scruss, 2021-05" --tag="GENRE=Ambient" --tag="TRACKNUMBER=1" --tag="TRACKTOTAL=1" "$outfile"
You’ll likely need these packages installed:
sudo apt install sox libsox-fmt-all ghostscript gsfonts-x11 netpbm lame flac libjpeg-progs
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The cheapest Micro SD card interface in the world
micro-SD adapter + pins + solder = working SD interface It’s only a serial SPI interface, but you can’t beat the price. It should only be used with 3.3 V micro-controllers like the Raspberry Pi Pico, since micro-SD cards don’t like 5 V directly at all.
You might want to pre-tin the pins and apply some extra flux on both surfaces, because these pads are thin and you don’t want to melt them. I used my standard SnAgCu lead-free solder without trouble, though.
got a label maker? This label’s the same length as an SD card is wide, as shown above.
Made entirely with netpbmYou only need to use one of the Ground connections for the card to work.
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cp2up.sh — fits the important part of Canada Post print labels two per sheet
no you will not read my 2-up shipping labels If you need to ship things, you’re probably not too keen on queuing at the post office right now. Canada Post’s Ship Online service is pretty handy if you have a printer. The PDFs it produces are okay to print on plain paper, but if you’re using full-sheet labels like Avery 5165 you’re going to waste half a sheet of expensive labels.
If you’ve got two parcels to mail, this shell script will extract the right side of each page and create a single 2-up PDF with both your labels on the same page. You will need:
On my Ubuntu system, you can get good-enough¹ versions by doing this:
sudo apt install poppler-utils netpbm img2pdf
The code:
#!/bin/bash # cp2up.sh - fits the important part of Canada Post print labels 2 per sheet # scruss, 2021-05 - CC-BY-SA # hard-coded input name (document.pdf) # hard-coded output name (labels-2up.pdf) # accepts exactly two labels (sorry) dpi=600 width_in=11 height_in=8.5 # png intermediate format uses pixels per metre dpm=$(echo "scale=3; $dpi * 1000 / 25.4" | bc) # calculated pixel sizes, truncated to integer half_width_px=$(echo "$width_in * $dpi / 2" | bc | sed 's/\..*$//') height_px=$(echo "$height_in * $dpi" | bc | sed 's/\..*$//') pdftoppm -mono -r "$dpi" -x "$half_width_px" -y 0 \ -W "$half_width_px" -H "$height_px" document.pdf labels pnmcat -lr labels-1.pbm labels-2.pbm |\ pnmtopng -compression 9 -phys "$dpm" "$dpm" 1 > labels.png \ && rm labels-1.pbm labels-2.pbm # fix PDF time stamps now=$(date --utc --iso-8601=seconds) img2pdf -o labels-2up.pdf --creationdate "$now" --moddate "$now" \ --pagesize "Letter^T" labels.png \ && rm labels.png # saved from: # history | tail | awk '{$1=""; print}' |\ # perl -pwle 'chomp;s/^\s+//;' > cp2up.shIt’s got a few hard-coded assumptions:
- input name (document.pdf);
- output name (labels-2up.pdf);
- accepts exactly two labels (sorry).
Clever people could write code to work around these. Really clever people could modify this to feed a dedicated label printer.
Yes, I could probably have done all this with one ImageMagick command. When ImageMagick’s command line syntax begins to make sense, however, it’s probably time to retire to that remote mountain cabin and write that million-word thesis on a manual typewriter. Also, ImageMagick’s PDF generation is best described as pish.
One of the issues that this script avoids is aliasing in the bar-codes. For reasons known only to the anonymous PDF rendering library used by Canada Post, their shipping bar-codes are stored as smallish (780 × 54 px) bitmaps that are scaled up to a 59 × 19 mm print size. Most PDF viewers (and Adobe Viewer is one of these) will anti-alias scaled images, making them slightly soft. If you’re really unlucky, your printer driver will output these as fuzzy lines that no bar-code scanner could ever read. Rendering them to high resolution mono images may still render the edges a little roughly, but they’ll be crisply rough, and scanners don’t seem to mind that.
fuzzy vs crisply rough: scaled image (top) vs direct-rendered (bottom), at simulated 600 dpi laser print resolution
¹: Debian/Ubuntu’s netpbm package is roughly 20 years out of date for reasons that only a very few nerds care about, and the much better package is blocked by Debian’s baroque and gatekeepery packaging protocol. I usually build it from source for those times I need the new features.
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Endless screaming in URL
A friend introduced me to A(x56) – URL Lengthener — perhaps better known as https://aaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.com/. Consequently, this website should in future be referred to as https://aaa.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.com/a?áaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂáaaÂåAæãæãæaæââÃáÆáÆæâåâæáæäæâæâáÅåâåÆåÄáÆåáåÃåÆåæáÆ.
It sounds even better than it reads:
that URL, as read by Flite
