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17 June 2021

Random thought: Fixing Java

If Oracle simply changes Java so that null.toString() returns the string "null" instead of throwing a NullPointerException, they will probably solve the majority of mysterious bugs in Java programs.

08 June 2021

Of blips and blobs...

Random thought . o O ( databases have blobs of binary data... Why not have blips of binary code? Blobs and blips... Blips and blobs... )

18 May 2021

Random thought: False Hope of Extensibility

Common Java anti-pattern is to name some classes as "DefaultFooClass" when there's actually no way to use any other implementation.

I think it should be called the "False Hope of Extensibility" anti-pattern.

01 May 2020

Standards have fallen. Disappointed by IEEE

Personally, I'm disappointed that the IEEE is reporting this as a good idea. It's not and I'll just outline a few of the issues:
- Horribly exothermic, a lot of lost energy.
- Did I say lost energy? Making aluminium from aluminium oxide takes a lot of energy.
- Hydrogen embrittling of the gasoline engine.
- Accelerated corrosion of the exhaust manifold.

Come on! This shouldn't even have passed a basic engineering review. This is basic A Level chemistry!

Photo: Kelly Wilkinson/Indy Star/USA TODAY Network/Imagn Content Services
Kurt Koehler, founder and president of AlGalCo, shows his HOT (Hydrogen on Tap) system, Thursday, April 9, 2020. It sits in a City of Carmel Street Department truck.

25 March 2019

Wooting LEDs from Java

While waiting for things at work, threw together a bit of Java code to tinker with the keyboard LEDs.. Pointless but fun. 😁 Note to self: Should make time to open source it this weekend so that other people can waste their time.
Posted by Antony T Curtis on Wednesday, 20 March 2019


21 February 2017

Lazy UPS drivers, again.

#Amazon #UPS #UPSfail Whenever it rains, their drivers are so lazy that they just mark packages as delivered without actually delivering them. Not the first time it has happened.

22 September 2016

Open Source Silicon?

A random thought:

I think it would be interesting if there was an open-source chip, perhaps based upon RISC-V, maybe based upon cores from SiFive, which are as easy to wire together into a mesh network with little-to-no external glue logic, to make massively parallel computing a commodity. Think of it like an open source Transputer. The Transputer processors had 4 I/O buses which could each directly interface with other processors, peripherals or there was a switch.
Today, we should be able to do better. Imagine a processor module which has perhaps 64 interconnected cores per package and 8 I/O channels and perhaps a couple of gigs of DRAM.

Hobbyists will then be able to experiment with different computing topologies:
or even

What makes this interesting is that this has been a largely dormant area of computer science for more than 20 years and I think with the possibility of open silicon, there's a lot of exciting areas for research and hobby tinkering.

07 September 2016

Java Rock Stars

The rock stars of the Java world never stay on a project long enough, departing immediately when it starts to need cleanup. That way, they're getting the accolades for their achievements and of the people left behind, managers think "these guys are so much less productive than the rock star; we were lucky to have the rock star to get the project started."

14 August 2016

Java 8 Streams

This code is certainly more terse from using Java 8 streams but is it more readable than it would be otherwise?
public synchronized void unregister(AsciiString uri, ChannelHandler handler) {
      .flatMap(l -> Optional.ofNullable(
          l.stream().filter(p -> p.second == handler)
           .filter(l::remove).findAny().isPresent() ? l : null))
      .ifPresent(l -> _handlerMap.remove(uri, l));}

28 March 2016

Upgrading a Rapide Lite 200 with a Smoothieboard 5x

The Rapide Lite 200 originally came with a RUMBA based controller board which is based upon an Atmel ATMEGA based microcontroller. However, I had encountered issues where the board's USB interface would reset during a print and thus ruining a print. The controller board uses a smaller Atmel microcontroller to provide the serial to USB interface and it's possible that there is some instability there.

Original Rapide controller

I had a Smoothieboard from a Kickstarter which I had intended to use for a CNC router project but I decided to repurpose it for upgrading the Rapide printer. The Smoothieware web site does have extensive information on making use of the Smoothieboard.

Smoothieboard 5x

The printer has 5 stepper motors, of which two are used to drive the y-axis. I could have chosen to drive both from the same driver chip but I decided to drive each of the stepper motors from their own driver. To make the two stepper motors step together, a few links had to be soldered onto the Smoothieboard. In order to keep things as simple as possible, I decided to keep the order in which the stepper motors plug onto the controller board the same. I also soldered the same connectors to the Smoothieboard to avoid needing to recrimp new connectors onto the cables.

Three jumpers centered
The were changes in the order of the power connectors. the power for the main board which was connected to the terminal labelled MAIN-PWR was then connected to the main board power input on the right of this image shown as 12-24v:
Be mindful to make sure that the polarity is correct.

The HB-PWR cables was then connected to the PWR IN connector at the bottom centre of the board and JP28 was jumpered for the fan power. The heater bed HB-OUT was then connected to P2_7 connector and the head heater HE0 connected to P2_5.

The thermistor and endstops were plugged in as one would expect.
Thermistor and endstop connections on original controller board

Initial install of smoothieboard
When I had initially set up the smoothieboard, I did not have the recommended 5V regulator installed so I had used a separate regulator board for the 5V power. I later installed the recommended 5V regulator (marked as VBB). I also ended up securing the board using adhesive PCB standoffs.

Cables tidied a bit and heatsinks added
The firmware install and upgrade is simply a case of putting the firmware.bin file in the root directory of a DOS formatted SDCARD. Instructions are available at: http://smoothieware.org/flashing-smoothie-firmware

A copy of my current config.txt is available here: config.txt

I do have my Smoothieboard plugged into my network so I have the ethernet enabled in my config.

12 October 2015

ILI9341 SPI Display on RISCOS Pico

It has been a fun mini-adventure to make the SPI LCD display work nicely on RISCOS...

There is a third-party module available to do communications on RISCOS, called PiSPI, but it is very basic and it takes more than a second to send all the data for refreshing the screen once. This effort started because I wanted to progress to investigating using the DMA engine on the Raspberry Pi, which is why the variable dmabuffer% contains the data in a format ready to be sent via the DMA engine. In any case, there is a lot of RAM available on the Raspberry Pi.

What is very convenient on RISCOS is the OS_SpriteOp system calls, which support creating sprites in many bit depths and sizes. It supports the 16bit format used by the display. Unfortunately, there is no call to rotate sprites and because the display is a 240x320 portrait display and I wanted to use it as if it was a 320x240 landscape display, I had to do that transformation for myself.

A few notes about this implementation:

  • GPIO25 is attached to the command/data pin of the display.
  • GPIO24 is attached to the reset pin of the display.
  • The SPI pins are attached as one would expect.
In spite of being "PIO" mode, performance is respectable.

Since this now works "good enough", I will proceed with other parts of my project and I may return to it when I need to get the DMA stuff working... Most likely because I'd like to find ways to reduce power consumption.
   10 REM >DMA9341
   30 spiclk%=4
   50 SYS "OS_SWINumberFromString",,"OS_SpriteOp" TO spriteOp%
   60 SYS "OS_SWINumberFromString",,"ColourTrans_SetGCOL" TO setGCOL%
   70 SYS "OS_SWINumberFromString",,"ColourTrans_ReturnColourNumber" TO getColourNumber%
   90 DIM vdurestore%(3)
  110 DIM code% 4096
  120 PRINT "Allocating scratchpad at ";~code%
  140 REM 320 * 240 * 16bit + 44 sprite header + 16 area header = 1536460
  150 DIM spritearea% 153660
  170 REM 320 * 240 * 16bit * 32bit words = 614400
  180 DIM dmabuffer% 614400
  200 spritearea%!0=153660
  210 spritearea%!4=0
  220 spritearea%!8=16
  230 spritearea%!12=16
  250 PRINT "Initializing sprite area at ";~spritearea%
  260 SYS spriteOp%,256+15,spritearea%,"lcd",0,320,240,&78a04001
  270 spriteptr%=spritearea%+16
  290 PRINT "Initializing sprite at ";~spriteptr%
  300 SYS spriteOp%,512+62,spritearea%,spriteptr% TO sarsize%
  320 DIM savearea% sarsize%
  330 PRINT "Initializing savearea at ";~savearea%
  340 savearea%!0=0
  360 SYS "OS_Memory",13,&20200000,&100 TO ,,,gpio%
  370 PRINT "GPIO mapped at ";~gpio%
  380 SYS "OS_Memory",13,&20204000,&100 TO ,,,spi%
  390 PRINT "SPI mapped at ";~spi%
  410 PROCinitGPIO
  430 DIM spiSendCode% 1024
  440 FOR pass%=0 TO 2 STEP 2
  450   P%=spiSendCode% : [ OPT pass%
  460   .spiSend
  470   SWI   "OS_EnterOS"
  480   ; SWI   256+65
  490   LDR   R3,gpiov
  500   MOV   R4,#1
  510   MOV   R2,R4,LSL #25
  520   STR   R2,[R3,#40]
  530   MCR   cp15,0,R3,c7,c10,5
  540   :
  550   LDR   R3,spiv
  560   LDR   R2,[R3,#0]
  570   AND   R2,R2,#&0c
  580   ORR   R2,R2,#&6b0
  590   STR   R2,[R3,#0]
  600   :
  610   MCR   cp15,0,R3,c7,c10,5
  620   STR   R0,[R3,#4]
  630   :
  640   .cmdwait
  650   MCR   cp15,0,R3,c7,c10,5
  660   LDR   R2,[R3,#0]
  670   TST   R2,#1<<16
  680   BEQ   cmdwait
  690   ; SWI   256+66
  700   TST   R2,#1<<17
  710   LDRNE R0,[R3,#4]
  720   ;ORR   R2,R2,#&30
  730   ;STR   R2,[R3,#0]
  740   :
  750   LDR   R3,gpiov
  760   MOV   R4,#1
  770   MOV   R2,R4,LSL #25
  780   STR   R2,[R3,#28]
  790   MCR   cp15,0,R3,c7,c10,5
  800   :
  810   LDR   R3,spiv
  820   :
  830   .isdone
  840   MOV   R0,R1
  850   ADD   R0,R0,#64
  860   CMP   R0,R5
  870   BHI   sendrem
  880   :
  890   ;SWI   256+67
  900   LDR   R0,[R1],#4
  910   STR   R0,[R3,#4]
  920   LDR   R0,[R1],#4
  930   STR   R0,[R3,#4]
  940   LDR   R0,[R1],#4
  950   STR   R0,[R3,#4]
  960   LDR   R0,[R1],#4
  970   STR   R0,[R3,#4]
  980   :
  990   LDR   R0,[R1],#4
 1000   STR   R0,[R3,#4]
 1010   LDR   R0,[R1],#4
 1020   STR   R0,[R3,#4]
 1030   LDR   R0,[R1],#4
 1040   STR   R0,[R3,#4]
 1050   LDR   R0,[R1],#4
 1060   STR   R0,[R3,#4]
 1070   :
 1080   LDR   R0,[R1],#4
 1090   STR   R0,[R3,#4]
 1100   LDR   R0,[R1],#4
 1110   STR   R0,[R3,#4]
 1120   LDR   R0,[R1],#4
 1130   STR   R0,[R3,#4]
 1140   LDR   R0,[R1],#4
 1150   STR   R0,[R3,#4]
 1160   :
 1170   LDR   R0,[R1],#4
 1180   STR   R0,[R3,#4]
 1190   LDR   R0,[R1],#4
 1200   STR   R0,[R3,#4]
 1210   LDR   R0,[R1],#4
 1220   STR   R0,[R3,#4]
 1230   LDR   R0,[R1],#4
 1240   STR   R0,[R3,#4]
 1250   :
 1260   CMP   R1,R5
 1270   BEQ   endsend
 1280   :
 1290   .bulk
 1300   ; SWI   256+72
 1310   MCR   cp15,0,R3,c7,c10,5
 1320   .busyloop
 1330   LDR   R2,[R3,#0]
 1340   TST   R2,#1<<16
 1350   BNE   isdone
 1360   TST   R2,#1<<19
 1370   ;MCREQ cp15,0,R3,c7,c0,4 ;wait for interrupt
 1380   BEQ   busyloop
 1390   :
 1400   ; SWI   256+73
 1410   MOV   R0,R1
 1420   ADD   R0,R0,#48
 1430   CMP   R0,R5
 1440   BHI   sendrem
 1450   :
 1460   ; SWI   256+74
 1470   LDR   R2,[R3,#4]
 1480   LDR   R0,[R1],#4
 1490   STR   R0,[R3,#4]
 1500   LDR   R2,[R3,#4]
 1510   LDR   R0,[R1],#4
 1520   STR   R0,[R3,#4]
 1530   LDR   R2,[R3,#4]
 1540   LDR   R0,[R1],#4
 1550   STR   R0,[R3,#4]
 1560   LDR   R2,[R3,#4]
 1570   LDR   R0,[R1],#4
 1580   STR   R0,[R3,#4]
 1590   :
 1600   LDR   R2,[R3,#4]
 1610   LDR   R0,[R1],#4
 1620   STR   R0,[R3,#4]
 1630   LDR   R2,[R3,#4]
 1640   LDR   R0,[R1],#4
 1650   STR   R0,[R3,#4]
 1660   LDR   R2,[R3,#4]
 1670   LDR   R0,[R1],#4
 1680   STR   R0,[R3,#4]
 1690   LDR   R2,[R3,#4]
 1700   LDR   R0,[R1],#4
 1710   STR   R0,[R3,#4]
 1720   :
 1730   LDR   R2,[R3,#4]
 1740   LDR   R0,[R1],#4
 1750   STR   R0,[R3,#4]
 1760   LDR   R2,[R3,#4]
 1770   LDR   R0,[R1],#4
 1780   STR   R0,[R3,#4]
 1790   LDR   R2,[R3,#4]
 1800   LDR   R0,[R1],#4
 1810   STR   R0,[R3,#4]
 1820   LDR   R2,[R3,#4]
 1830   LDR   R0,[R1],#4
 1840   STR   R0,[R3,#4]
 1850   :
 1860   CMP   R1,R5
 1870   BNE   bulk
 1880   :
 1890   .endsend
 1900   ; SWI   256+69
 1910   .endloop
 1920   MCR   CP15,0,R3,c7,c10,5
 1930   LDR   R2,[R3,#0]
 1940   TST   R2,#1<<17
 1950   LDRNE R0,[R3,#4]
 1960   TST   R2,#1<<16
 1970   BEQ   endloop
 1980   :
 1990   ORR   R2,R2,#&30
 2000   BIC   R2,R2,#&80
 2010   STR   R2,[R3,#0]
 2020   :
 2030   SWI   "OS_LeaveOS"
 2040   :
 2050   MOV   PC,R14
 2060   :
 2070   .sendrem
 2080   ; SWI   256+68
 2090   CMP   R1,R5
 2100   BEQ   endsend
 2110   LDR   R0,[R1],#4
 2120   STR   R0,[R3,#4]
 2130   BAL   sendrem
 2140   :
 2150   .gpiov
 2160   EQUD  gpio%
 2170   .spiv
 2180   EQUD  spi%
 2190   .SPI_AND_MASK
 2200   EQUD  &0000000c
 2210   .SPI_OR_MASK
 2220   EQUD  &000006b0
 2230   :
 2250   .lineblt
 2260   LDR   R1,[R0],#4
 2270   MOV   R4,R1,LSR #8
 2280   AND   R3,R1,#&ff
 2290   AND   R4,R4,#&ff
 2300   STR   R4,[R2],#4
 2310   STR   R3,[R2],#-&784
 2320   MOV   R4,R1,LSR #24
 2330   MOV   R3,R1,LSR #16
 2340   AND   R4,R4,#&ff
 2350   AND   R3,R3,#&ff
 2360   STR   R4,[R2],#4
 2370   STR   R3,[R2],#-&784
 2380   CMP   R5,R2
 2390   MOVHI PC,R14
 2400   BAL   lineblt
 2410   :
 2420 ] : NEXT pass%
 2440 PRINT "Resetting LCD display"
 2450 PROClcdReset
 2460 PRINT "Initializing LCD display"
 2470 PROClcdSetup
 2480 PRINT "Performing first update"
 2490 start%=TIME:PROClcdUpdate:PRINT "Took ";(TIME-start%)/100;" seconds"
 2500 REM PRINT "again"
 2510 REM PROClcdUpdate
 2520 REM END
 2530 PRINT "Running PROCtest"
 2540 PROCtest
 2560 END
 2580 DEF PROCspi(cmd%,addr%,end%)
 2590 REM PRINT "PROCspi(&";~cmd%;",&";~addr%;",&";~end%;")"
 2600 A%=cmd%:B%=addr%:F%=end%
 2610 CALL spiSend
 2640 DEF PROClcdUpdate
 2650 LOCAL y%
 2660 A%=spriteptr%+44
 2670 FOR y%=dmabuffer% TO dmabuffer%+&778 STEP 8
 2680   C%=y%+&95880:F%=y%:A%=USR lineblt
 2690 NEXT y%
 2700 PROCspi(&2c,dmabuffer%,dmabuffer%+614400)
 2730 DEF PROCsetGCOL(rgb%)
 2740 SYS setGCOL%,rgb%,,,0,3
 2770 DEF PROCsetColour(rgb%)
 2780 LOCAL colour%
 2790 SYS getColourNumber,rgb% TO colour%
 2800 COLOUR colour%
 2830 DEF PROCtest2
 2840 LOCAL x%,y%,p%
 2850 p%=spriteptr%+44
 2860 FOR y%=0 TO 239
 2870   FOR x%=0 TO 319
 2880     IF (x% AND &4)=(y% AND &4) THEN
 2890       p%?0 = &ff
 2900       p%?1 = &ff
 2910       ELSE
 2920       p%?0 = &00
 2930       p%?1 = &00
 2940     ENDIF
 2950     p%=p%+2
 2960   NEXT x%
 2970 NEXT y%
 2980 PROClcdUpdate
 3010 DEF PROCtest
 3020 LOCAL start%,end%,c%
 3030 PROCvduLcdSprite
 3050 PRINT "Hello World from RISCOS"
 3060 start%=TIME:PROClcdUpdate:end%=TIME
 3070 PRINT
 3090 PRINT "frame refresh takes ";(end%-start%)/100;" seconds"
 3110 FOR c%=0 TO 63
 3120   COLOUR c%
 3130   PRINT "*";
 3140 NEXT c%
 3170 PROCvduRestore
 3180 PROClcdUpdate
 3210 DEF PROCvduLcdSprite
 3220 IF vdurestore%(0) THEN
 3230   ERR 6,"Cannot switch"
 3240   ELSE
 3250   SYS spriteOp%,60+512,spritearea%,spriteptr%,savearea% TO vdurestore%(0),vdurestore%(1),vdurestore%(2),vdurestore%(3)
 3260 ENDIF
 3290 DEF PROCvduRestore
 3300 IF vdurestore%(0) THEN
 3310   SYS spriteOp%,vdurestore%(0),vdurestore%(1),vdurestore%(2),vdurestore%(3)
 3320   vdurestore%(0)=0
 3330   ELSE
 3340   ERR 6,"Cannot restore"
 3350 ENDIF
 3380 DEF PROCinitGPIO
 3390 LOCAL pass%
 3400 FOR pass%=0 TO 2 STEP 2
 3410   P%=code% : [ OPT pass%
 3420   .start
 3430   SWI   "OS_EnterOS"
 3440   LDR   R0, GPSEL0_OR_MASK
 3450   LDR   R2,[R1,#0]
 3460   ORR   R2,R2,R0
 3470   LDR   R0, GPSEL0_AND_MASK
 3480   AND   R2,R2,R0
 3490   STR   R2,[R1,#0]
 3500   LDR   R0,GPSEL1_OR_MASK
 3510   LDR   R2,[R1,#4]
 3520   ORR   R2,R2,R0
 3530   LDR   R0,GPSEL1_AND_MASK
 3540   AND   R2,R2,R0
 3550   STR   R2,[R1,#4]
 3560   ;LDR   R0,GPSEL2_OR_MASK
 3570   ;LDR   R2,[R1,#8]
 3580   ;ORR   R2,R2,R0
 3590   ;LDR   R0,GPSEL2_AND_MASK
 3600   ;AND   R2,R2,R0
 3610   ;STR   R2,[R1,#8]
 3620   MOV   R0,#%11<<6
 3630   STR   R0,[R1,#&1c]
 3640   MOV   R0,#%111<<9
 3650   STR   R0,[R1,#&28]
 3660   MOV   R0,#&3c
 3670   STR   R0,[R3,#0]
 3680   MOV   R0,#spiclk%
 3690   STR   R0,[R3,#&8]
 3700   SWI   "OS_LeaveOS"
 3710   MOV   PC,R14
 3720   :
 3730   .GPSEL0_OR_MASK
 3740   EQUD  &24800000
 3750   :
 3760   .GPSEL0_AND_MASK
 3770   EQUD  &249fffff
 3780   :
 3790   .GPSEL1_OR_MASK
 3800   EQUD  &00000024
 3810   :
 3820   .GPSEL1_AND_MASK
 3830   EQUD  &2fffffe4
 3840   :
 3850   .GPSEL2_OR_MASK
 3860   EQUD  &00024000
 3870   :
 3880   .GPSEL2_AND_MASK
 3890   EQUD  &fffc0fff
 3900 ] : NEXT pass%
 3910 B%=gpio%:D%=spi%
 3920 CALL start
 3930 SYS "GPIO_WriteMode",24,1
 3940 SYS "GPIO_WriteMode",25,1
 3970 DEF PROClcdSetup
 3990 RESTORE +0
 4000 DATA &1ef,&03,&80,&02
 4010 DATA &1cf,&00,&c1,&30
 4020 DATA &1ed,&64,&03,&12,&81
 4030 DATA &1e8,&85,&00,&78
 4040 DATA &1cb,&39,&2c,&00,&34,&02
 4050 DATA &1f7,&20
 4060 DATA &1ea,&00,&00
 4070 DATA &1c0,&23
 4080 DATA &1c1,&10
 4090 DATA &1c5,&3e,&28
 4100 DATA &1c7,&86
 4110 DATA &136,&48
 4120 DATA &13a,&55
 4130 DATA &1b1,&00,&18
 4140 DATA &1b6,&08,&82,&27
 4150 DATA &1f2,&00
 4160 DATA &126,&01
 4170 DATA &1e0,&0f,&31,&2b,&0c,&0e,&08,&4e,&f1,&37,&07,&10,&03,&0e,&09,&00
 4180 DATA &1e1,&00,&0e,&14,&03,&11,&07,&31,&c1,&48,&08,&0f,&0c,&31,&36,&0f
 4190 DATA &111
 4200 DATA -1
 4210 PROClcdSendInitData
 4220 PROCsleep(0.120)
 4230 PROCspi(&29,code%,code%)
 4250 ENDPROC                                                                  :
 4260 :
 4270 DEF PROClcdSendInitData
 4280 LOCAL ptr%
 4290 ptr%=code%
 4300 READ !ptr%
 4310 WHILE -1<!ptr%
 4320   !ptr%=&ff AND !ptr%
 4330   ptr%=ptr%+4
 4340   READ !ptr%
 4350   WHILE (&100 AND !ptr%)=0
 4360     ptr%=ptr%+4
 4370     READ !ptr%
 4380   ENDWHILE
 4390   PROCspi(!code%,code%+4,ptr%)
 4400   !code%=!ptr%
 4410   ptr%=code%
 4440 :
 4450 DEF PROCsleep(d)
 4460 ptr%=d*100+TIME:REPEAT:WAIT:UNTIL TIME>=ptr%
 4480 :
 4490 DEF PROClcdReset
 4500 SYS "GPIO_WriteData",24,1
 4510 PROCsleep(0.005)
 4520 SYS "GPIO_WriteData",24,0
 4530 PROCsleep(0.020)
 4540 SYS "GPIO_WriteData",24,1
 4550 PROCsleep(0.150)

01 July 2015

A random thought regarding copyrights...

So... Oracle's suit regarding the copyrights of APIs has been upheld by the SCOTUS...

a random thought entered my mind: The HTTP protocol may be considered an API and every access to some URL which causes code to be executed is an API... Perhaps Google could stop indexing all Oracle properties on the web because they could "fear" being sued for misappropriating Oracle's APIs and require that Oracle submit by postal mail a letter from their lawyers with permission to index a page, including the URL and SHA2 hash of each page where Oracle gives Google permission to copy for indexing purposes. Then Google will only list pages which matches the provided SHA2 hash.

21 June 2015

Mucking around with ZooKeeper and Netty 4

ZooKeeper using Netty4 with a common netty worker pool...
Would be trivial to switch it to use the Netty 4 epoll implementation.

Now... To continue what I started hacking on ...

0 [main] INFO org.apache.zookeeper.server.ZooKeeperServer  - Server environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT
39 [main] INFO org.apache.zookeeper.server.ZooKeeperServer - Created server with tickTime 3000 minSessionTimeout 6000 maxSessionTimeout 60000 datadir /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T/org.xiphis.zookeeper.TestZookeeper/zksnap/version-2 snapdir /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T/org.xiphis.zookeeper.TestZookeeper/zklog/version-2
54 [main] DEBUG io.netty.util.internal.logging.InternalLoggerFactory - Using SLF4J as the default logging framework
60 [main] DEBUG io.netty.util.internal.PlatformDependent0 - java.nio.Buffer.address: available
61 [main] DEBUG io.netty.util.internal.PlatformDependent0 - sun.misc.Unsafe.theUnsafe: available
61 [main] DEBUG io.netty.util.internal.PlatformDependent0 - sun.misc.Unsafe.copyMemory: available
62 [main] DEBUG io.netty.util.internal.PlatformDependent0 - java.nio.Bits.unaligned: true
64 [main] DEBUG io.netty.util.internal.PlatformDependent - Java version: 8
65 [main] DEBUG io.netty.util.internal.PlatformDependent - -Dio.netty.noUnsafe: false
65 [main] DEBUG io.netty.util.internal.PlatformDependent - sun.misc.Unsafe: available
66 [main] DEBUG io.netty.util.internal.PlatformDependent - -Dio.netty.noJavassist: false
68 [main] DEBUG io.netty.util.internal.PlatformDependent - Javassist: unavailable
68 [main] DEBUG io.netty.util.internal.PlatformDependent - You don't have Javassist in your class path or you don't have enough permission to load dynamically generated classes. Please check the configuration for better performance.
69 [main] DEBUG io.netty.util.internal.PlatformDependent - -Dio.netty.tmpdir: /var/folders/4l/kmd0x0_x0q587n81vrrfjks40000z9/T (java.io.tmpdir)
69 [main] DEBUG io.netty.util.internal.PlatformDependent - -Dio.netty.bitMode: 64 (sun.arch.data.model)
69 [main] DEBUG io.netty.util.internal.PlatformDependent - -Dio.netty.noPreferDirect: false
111 [main] DEBUG io.netty.channel.MultithreadEventLoopGroup - -Dio.netty.eventLoopThreads: 8
172 [main] DEBUG io.netty.channel.nio.NioEventLoop - -Dio.netty.noKeySetOptimization: false
172 [main] DEBUG io.netty.channel.nio.NioEventLoop - -Dio.netty.selectorAutoRebuildThreshold: 512
208 [main] INFO org.apache.zookeeper.server.Netty4ServerCnxnFactory - binding to port
236 [main] DEBUG io.netty.util.internal.ThreadLocalRandom - -Dio.netty.initialSeedUniquifier: 0x1216b72d21d3cb0f (took 13 ms)
278 [main] DEBUG io.netty.buffer.ByteBufUtil - -Dio.netty.allocator.type: unpooled
278 [main] DEBUG io.netty.buffer.ByteBufUtil - -Dio.netty.threadLocalDirectBufferSize: 65536
282 [main] DEBUG io.netty.util.NetUtil - Loopback interface: lo0 (lo0, 0:0:0:0:0:0:0:1)
282 [main] DEBUG io.netty.util.NetUtil - /proc/sys/net/core/somaxconn: 128 (non-existent)

19 January 2015

Global Internet Access

There appears to be a rash of billionaires announcing support for the idea of a global satellite-based internet service, for example: http://www.extremetech.com/extreme/197711-elon-musk-unveils-new-plan-to-circle-to-earth-in-satellites-for-fast-low-latency-internet

I would wager that if we have had good affordable internet in our first-world abodes, the wealthy would not be so inclined to think of such schemes. Like as like not, for a new third-party to compete on the ground is practically impossible due to legal red tape and so the space option becomes the most practical, in spite of being a bit inefficient. It's easy to imagine the Elon Musks of the world venting frustration about lack of coverage or simply being unable to cancel Comcast without losing sanity...

Of course, when the time comes, the legacy telcos will complain about unfair competition from these upstarts and will campaign for government hand-outs to help modernise their networks; something which they should already be doing instead of accumulating profit and giving the money to their directors and shareholders.

It will be curious to see what happens. Ideally, the telcos will see the light; otherwise, I won't lose any sleep as their networks decay into obsolescence.

13 January 2015

Fox news Christian terrorists

Christian terrorist Jeanine Pirro, calling for a jihad/crusade to mass murder other people because other places which have tried mass murder worked out great.

I'm all for free speech except when it's threats, advocating violence or inciting violence.

Unlike the fox gaffe earlier this week, this is not funny.


01 December 2014

Rowhammer: ECC DRAM by default?

Apparently, there has been a weakness in modern DRAM which had been known within the computing industry since 2012 which has been given name rowhammer. It is particularly the interesting because if how nearby memory locations have their bits flipped which violates the very foundation of our modern multiprocess systems.
Perhaps, it is time that all our PCs should have ECC memory by default which would at least fix single bit disturbances?

25 November 2014

Some project foundation classes for Java.

Have been organising and repackaging some of my source code for release as free open source code. The flavour du jour is Java and these are just a few foundation classes which will be built upon in further packages, hopefully released soon (time permitting). #OpenSource #BSD #Java https://github.com/xiphis/xiphis-utils

13 November 2014

Oh, how editing standards at The Guardian has fallen.

The Guardian posted this article, entitled: Women, beware this PUA army of sleazebags, saddos and weirdos by Hadley Freeman
"They’re sci-fi saddos; they’re World of Warcraft weirdos"
As someone who enjoys sci-fi and whose name is in the credits for more than one WoW game, this is inappropriate offensive mischaracterization. Some people are jerks because that is simply what they are and it has nothing to do with what fiction genre they enjoy or what computer games they have played.
I guess The Guardian is becoming just another sleazy tabloid with ineffective editors.


Originally posted at Facebook

07 August 2014

The right tool for the job...

I've just thought of a great analogy for something:

Imagine that a team has an OKR:

  • Objective: Secure a piece of wood to another piece of wood.
  • Key Results:
    1. Select a suitable fastener.
    2. Select a suitable tool.
    3. Fasten the pieces of wood together.

The team chooses a good wood screw.
The team chooses a good electric screwdriver.

The two items are designed to work together.

The team puts the wood screw into the hole.
The team then proceeds to use the electric screwdriver as a hammer,
hammering the screw into the hole.
Bits of the electric screwdriver shatter. The head of the screw is mangled.

OKR objective and key results achieved.

Now imagine that someone needs to fix this, afterwards.

31 July 2014

Opinion: Blogging about homophones and homonyms.

Homophones and homonyms are two very important aspects of the English language which non-native speakers of the language need to understand in order to adequately communicate unambiguously with native English speakers. If this person was fired for blogging about them from a "language school", then it can't have been a good language school.