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by Bakul Shah
Thu May 07, 2015 7:06 pm
Forum: Plan 9
Topic: Plan 9 on Raspberry Pi 2
Replies: 4
Views: 15058

Re: Plan 9 on Raspberry Pi 2

kyounger wrote:so has 9pi been made to work on Pi2 with SMP enabled? if so, is there a iso somewhere?
Yes. You can pick up 9pi.img.gz from the link supllied in the first message in this thread.
by Bakul Shah
Fri Feb 06, 2015 6:49 pm
Forum: General discussion
Topic: The Raspberry Pi 2 Q&A thread
Replies: 442
Views: 113549

Re: The Raspberry Pi 2 Q&A thread

I reread the Sept 19, 2012 blog post on the turbo mode (aka the irreversible bit and the voided warranty) but am still not clear. If the bit is set, is the warranty voided? In the context of Pi2, are there any settings (manually done) that will void the warranty?

Thanks!
by Bakul Shah
Wed Aug 27, 2014 7:04 am
Forum: FreeBSD
Topic: Unable to build any ports
Replies: 7
Views: 2639

Re: Unable to build any ports

Has anyone successfully built any port on a Raspberry Pi? I've tried a few but get lots of errors which I don't understand and can't help wondering if I've missed something... When building a port is there normally a buildlog so that I have a record of any error messages generated? I would love to ...
by Bakul Shah
Mon Jul 07, 2014 5:54 pm
Forum: Graphics, sound and multimedia
Topic: Raspberry Pi and 4k @ 15Hz
Replies: 123
Views: 166703

Re: Raspberry Pi and 4k @ 15Hz

Interesting. Can you get 3840 x 2160 @ 24Hz? You may need to increase the hdmi pixel clock limit. It defaults to 163682864. Perhaps try hdmi_pixel_freq_limit=400000000 What is the highest supported pixel clock frequency? On plan9 I can get "4k" @20Hz but at 24Hz the display seems to turn itself off...
by Bakul Shah
Sun Nov 03, 2013 7:50 pm
Forum: Beginners
Topic: IP address for crossover cable
Replies: 36
Views: 4838

Re: IP address for crossover cable

To test, you can just use telnet, no need for the client program! On the linux machine just do telnet 192.168.1.1 1234 It should return something like Trying 192.168.1.1... Connected to 192.168.1.1. Escape character is '^]'. To get out type ctl-] followed with q. If this works then the problem is in...
by Bakul Shah
Sun Nov 03, 2013 7:22 pm
Forum: Other programming languages
Topic: Asm tuts
Replies: 63
Views: 17593

Re: Asm tuts

If you're seeing odd characters, they are coming from the tools you're using to cut / paste / edit. Still, to save time, assuming you've saved to a file, try this: perl -pi -e 's/\s/ /misg' filename.txt …which will move all "whitespace" characters to plain ascii spaces. Shouldn't take more than a m...
by Bakul Shah
Thu Oct 17, 2013 1:02 pm
Forum: Staffroom, classroom and projects
Topic: BASIC - more harmful than useful?
Replies: 899
Views: 143225

Re: BASIC - more harmful than useful?

[Edit: Man, that Loop construct in Scheme is WEIRD] Basically (let foo ((arg1 val1) ...) body) is equivalent to (begin (define (foo arg1 ...) body) (foo val1 ...)) When you call foo as the last thing from body, you've got a loop since in Scheme tail recursion is guaranteed to not increase stack spa...
by Bakul Shah
Tue Oct 15, 2013 8:53 am
Forum: Other programming languages
Topic: Brand New Graphical Development System
Replies: 54
Views: 10313

Re: Brand New Graphical Development System

Search for visual programming language or data flow language. You'll find lots of stuff. IMHO it would be hard to come up with something innovative that is easy to use and scales to realistic program sizes. But don't let other people's skepticism stop you if you think you have a great idea! In terms...
by Bakul Shah
Wed Sep 25, 2013 7:14 am
Forum: Plan 9
Topic: '\|' Key and Recompiling Kernel
Replies: 2
Views: 11627

Re: '\|' Key and Recompiling Kernel

I have a non-responsive '\|' key. I have followed the instructions from https://groups.google.com/forum/#!topic/comp.os.plan9/ycok6NTCWCg and by editing /sys/lib/kbmap/uk I now have the '\' working. To get the shift+'\|' to give me '|' I have edited /sys/src/9/omap/kbd.c if(kbscan->esc1 && c != 0x5...
by Bakul Shah
Mon Jul 08, 2013 5:54 pm
Forum: General discussion
Topic: Project idea: Pool Water Leveler
Replies: 23
Views: 5233

Re: Project idea: Pool Water Leveler

Reviews of commercial pool levelers on Amazon can give you an idea of what works well. Everyone seems to be using a float. Using an RPi for this seems like an overkill as this is a very simple closed loop system. An ATtiny would be more reliable, use less power etc. You can wake it up once a day to ...
by Bakul Shah
Mon Jul 08, 2013 4:41 pm
Forum: Staffroom, classroom and projects
Topic: kitting out a classroom
Replies: 128
Views: 39006

Re: kitting out a classroom

Checks the contents of local_server/home/$USER and copies the contents to remote_server/home/$USER every evening? csync2 can be used to keep files on multiple hosts in sync (I have played with it some but no real experience). There is also lsyncd (live sync daemon). As for sharing home directories,...
by Bakul Shah
Mon Jul 08, 2013 7:28 am
Forum: Off topic discussion
Topic: I think there is a world market for maybe five computers...
Replies: 23
Views: 4280

Re: I think there is a world market for maybe five computers

I once read that the whole miniaturization and going to devices like the 7400 series was possible because of the need (and willingness to pay) of the Apollo program for such devices. Curious in how far THAT is true. You read that right! From PBS's absolutely fascinating Silicon Valley program: Narr...
by Bakul Shah
Sat Jul 06, 2013 9:01 am
Forum: General discussion
Topic: code.org
Replies: 15
Views: 1994

Re: code.org

I have a different POV from Jim and Heater. To me coding is just another skill like reading, writing and arithmetic. Just as knowing arithmetic doesn't limit your career choice to being an accountant or a number theorist or an actuary, knowing coding doesn't mean you are limited to being a programme...
by Bakul Shah
Thu Jul 04, 2013 6:16 pm
Forum: Bare metal, Assembly language
Topic: chess in assembly!
Replies: 36
Views: 13978

Re: chess in assembly!

Very impressive! The assembly language program is easy to read -- very cleanly done (using equivalent C code as a comment is something I too use when writing asm code).

As your next assignment please add alpha-beta search so that you can pit a pi against a person or another pi.
Just kidding :-)
by Bakul Shah
Thu Jul 04, 2013 6:00 pm
Forum: General discussion
Topic: Setting hostname dymanically
Replies: 21
Views: 9727

Re: Setting hostname dymanically

4. I want one image to deploy to all pi's ... I am looking for a suggestion on how to set the hostname automatically to a unique value (i.e. MAC address or something else unique) so that all my Pi's don't have 'rpitc' as their hostname? Typically a DHCP server in your org's network gives a machine ...
by Bakul Shah
Thu Jul 04, 2013 8:56 am
Forum: General discussion
Topic: Setting hostname dymanically
Replies: 21
Views: 9727

Re: Setting hostname dymanically

Not sure what you're trying to do but you shouldn't have to do anything special on individual hosts. Assuming there is a DHCP server on your network, you can associate mac address and host name for each RPi on the server.
by Bakul Shah
Thu Jul 04, 2013 8:47 am
Forum: General discussion
Topic: Computing Pioneer Doug Englebart Has Passed Away
Replies: 10
Views: 1898

Re: Computing Pioneer Doug Englebart Has Passed Away

Here is the whole the mother of all demos . This video feels like an old scifi TV show what with its beeps, buzzes & Engelbart's voice over but this was no StarTrek but shape of things to come! If you pay attention you can recognize start of an enormous number of stuff we take for granted now. Just ...
by Bakul Shah
Wed Jul 03, 2013 9:27 am
Forum: C/C++
Topic: Question on fork()
Replies: 7
Views: 2049

Re: Question on fork()

Lookup Project Genie, a research project at UC Berkeley. fork() was first implemented in the berkeley timesharing system on sds940 during 1964-1967. In fact they called processes forks! Ken Thompson worked on sds940.
by Bakul Shah
Mon Jul 01, 2013 5:18 pm
Forum: General discussion
Topic: How long can I run the RasPi for?
Replies: 21
Views: 4946

Re: How long can I run the RasPi for?

The hero points still go to QNX. Their salesman told us of one machine that had been running non-stop for seven years, and in that time it had had complete upgrades of both the application and the operating system. (Linux has loadable modules in the kernel which can be upgraded and reloaded without...
by Bakul Shah
Sun Jun 30, 2013 8:40 pm
Forum: C/C++
Topic: Max31855 Thermistor - C code to convert bits to decimal
Replies: 4
Views: 1878

Re: Max31855 Thermistor - C code to convert bits to decimal

and in twos complement representation Bakul Shah, I'm not sure I understand how this works? You mean theres no actual system of conversion that makes sense here? How can each bit represent 0.25 degrees, when a second bit indicates a unique value? I know how to print in dec/hex etc, but the conversi...
by Bakul Shah
Sun Jun 30, 2013 5:48 pm
Forum: C/C++
Topic: Max31855 Thermistor - C code to convert bits to decimal
Replies: 4
Views: 1878

Re: Max31855 Thermistor - C code to convert bits to decimal

From the table it seems the temp. readings in units of quarter degrees and in twos complement representation. You have two choices. If you want 0.25 degree precision use floating point: float temp = 0.25 * reading; If you want to use just ints, you will have to lose some resolution. int temp = readi...
by Bakul Shah
Sun Jun 30, 2013 5:23 pm
Forum: C/C++
Topic: Calling system() from daemon
Replies: 4
Views: 1182

Re: Calling system() from daemon

Do you want your server program to run even while you are logged out? If so, use daemon(). A proper daemon that is supposed to always run should do a few more things in addition to calling (or emulating the logic of) daemon(). Read a few daemons' manpages to get an idea. Or may be someone has a webp...
by Bakul Shah
Sun Jun 30, 2013 7:37 am
Forum: General discussion
Topic: Please help what is happening
Replies: 26
Views: 3764

Re: Please help what is happening

OK I am trying to connect to my new raspberri pi through my mac. Basically when I power on the pi the red light comes on and yellow then the green ones flicker then it ends up they are all on. Does that mean it has booted up correctly because I can not seam to find the ip address. the ethernet cabl...
by Bakul Shah
Sun Jun 30, 2013 7:05 am
Forum: Automation, sensing and robotics
Topic: Understanding how RPI gets its time
Replies: 4
Views: 1218

Re: Understanding how RPI gets its time

I want to add a DS1307 real time clock module to RPI so it can set its time at startup when it has no internet connection, then when network time service becomes available, RPI periodically updates DS1307 (say once a day to make up the inaccuracy of DS1307). Is there any simple way to achieve the a...
by Bakul Shah
Fri Jun 28, 2013 12:28 am
Forum: Plan 9
Topic: New plan9 image
Replies: 0
Views: 11506

New plan9 image

Richard has put a new plan9 image in http://plan9.bell-labs.com/sources/contrib/miller/9pi.img.gz . Not much is new but it should work with model-A RPi now + it is updated for 21 bit runes. To keep your sources uptodate, you can use the pull command. To avoid downloading x86 bits (about 235MB), repl...

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