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by Bakul Shah
Sun Dec 09, 2012 7:12 pm
Forum: Plan 9
Topic: Quid pro quo
Replies: 2
Views: 8693

Re: Quid pro quo

Florent wrote:I'll be happy to help him out and I'm waiting for my eLinux account request to be approved.
I got my acct. Liz will have her quid in a bit but it won't be very pro.
by Bakul Shah
Sat Dec 08, 2012 9:44 pm
Forum: Bare metal, Assembly language
Topic: Bootloader Questions
Replies: 19
Views: 5753

Re: Bootloader Questions

The bootloader obviously isn't intended for persistent programs. It's intended for use during the development phase, so that you won't have to copy your program/kernel to the SD card every time you have an update to evaluate. If you want it persistent, just replace the bootloader with your program ...
by Bakul Shah
Mon Nov 19, 2012 3:56 am
Forum: Off topic discussion
Topic: What's wrong with the OS status quo & how to fix it
Replies: 27
Views: 3476

Re: Other ARM hardware?

Your assuming that the current OS paradigm is broken, which isn't proved, in my mind anyway. For example, no-one has yet given me a good alternative, or at least explained the alternatives in the words of one syllable I need in order to understand 'paradigm shifts'. And until that happens, the curr...
by Bakul Shah
Thu Nov 15, 2012 2:20 am
Forum: Off topic discussion
Topic: What's wrong with the OS status quo & how to fix it
Replies: 27
Views: 3476

Re: Other ARM hardware?

I don't believe anyone has come up with an alternative. The existing file paradigm is pretty limiting, but I have seen nothing that gives the same unity and utility, much less a step change in expressibility or efficiency. Compared to unix the file paradigm has been taken much further in plan9[1]. ...
by Bakul Shah
Sun Nov 04, 2012 6:28 am
Forum: Staffroom, classroom and projects
Topic: APL
Replies: 10
Views: 3337

Re: APL

Kona is an open-source implementation of the K programming language. If you don't know APL, then this is the place to start. K is an ASCII-based APL. To build it on the Raspi: $ git clone https://github.com/kevinlawler/kona.git $ cd kona $ make To use: $ rlwrap ./k # rlwrap for history and command l...
by Bakul Shah
Thu Nov 01, 2012 6:01 pm
Forum: General discussion
Topic: RaspberryPi On/Off Switch Idea
Replies: 81
Views: 51623

Re: RaspberryPi On/Off Switch Idea

There's also a ready made solution: http://www.pololu.com/catalog/product/751 , I'm not sure if it has the "hold for x seconds to do hard off" or not but in most cases you don't want to do a hard-off to avoid SD card corruption. The circuit I referenced earlier does this. You need an output signal ...
by Bakul Shah
Thu Nov 01, 2012 5:06 pm
Forum: General discussion
Topic: RaspberryPi On/Off Switch Idea
Replies: 81
Views: 51623

Re: RaspberryPi On/Off Switch Idea

There's also a ready made solution: http://www.pololu.com/catalog/product/751 , I'm not sure if it has the "hold for x seconds to do hard off" or not but in most cases you don't want to do a hard-off to avoid SD card corruption. The circuit I referenced earlier does this. You need an output signal ...
by Bakul Shah
Fri Oct 26, 2012 6:38 pm
Forum: General discussion
Topic: RaspberryPi On/Off Switch Idea
Replies: 81
Views: 51623

Re: RaspberryPi On/Off Switch Idea

Bakul Shah wrote:Sorry, no circuit diagram.
Forgot to mention. http://cds.linear.com/docs/Datasheet/2954fb.pdf shows some sample applications that may help.
by Bakul Shah
Fri Oct 26, 2012 5:23 pm
Forum: General discussion
Topic: RaspberryPi On/Off Switch Idea
Replies: 81
Views: 51623

Re: RaspberryPi On/Off Switch Idea

Sorry, no circuit diagram.
by Bakul Shah
Fri Oct 26, 2012 4:54 pm
Forum: General discussion
Topic: Big open news!
Replies: 58
Views: 7962

Re: Big open news!

Even if you somehow manage to create and piggyback a virus on start.elf, You have to get it to the gpu. That means replacing start.elf on the plugged in flash card. That can happen if you have physical access to the card or can remotely log in to an account with write privileges to /boot. If you hav...
by Bakul Shah
Thu Oct 25, 2012 10:41 pm
Forum: General discussion
Topic: Big open news!
Replies: 58
Views: 7962

Re: Big open news!

asb wrote:Bakul Shah: yes, Richard has done a very impressive job and we do talk to him.
Great! Thanks!
by Bakul Shah
Thu Oct 25, 2012 9:59 pm
Forum: General discussion
Topic: Big open news!
Replies: 58
Views: 7962

Re: Big open news!

It has absolutely as much appeal for me because: 1 - I'm writing a non-linux OS, knowing how to do accelerated graphics means I can be on a par with linux, at least. 2 - I also note some emmc code in there, which might save some time 3 - doing the pre rendering / rasterising / compositing donkeywor...
by Bakul Shah
Wed Oct 24, 2012 5:52 pm
Forum: General discussion
Topic: RaspberryPi On/Off Switch Idea
Replies: 81
Views: 51623

Re: RaspberryPi On/Off Switch Idea

A friend of mine dug up this Linear part, http://www.linear.com/product/LTC2954 which seems about perfect! When power is off , a short press on the push button to turn it on. When power is on , a short press to interrupt the µprocessor. It can then save its state and shut itself down. If the µP doe...
by Bakul Shah
Wed Oct 24, 2012 5:32 pm
Forum: General discussion
Topic: Big open news!
Replies: 58
Views: 7962

Re: Big open news!

Excellent news! Congratulations and Thanks to all involved @ RPF & Broadcom! [BTW, I tried posting this on the blog entry for this but attempts from Opera as well as Safari failed] Edit: looks like it got through to the blog entry. Thanks! BTW, nice to know you guys are following the Plan9 work! Its...
by Bakul Shah
Fri Oct 05, 2012 8:09 pm
Forum: Bare metal, Assembly language
Topic: Bare metal qemu-system-arm
Replies: 10
Views: 6752

Re: Bare metal qemu-system-arm

Fair enough! Thanks all. I do have a real machine, but find it a much shorter edit-compile-debug cycle when using qemu. Fortunately it looks like it's not too much of a hurdle to get to LED control and frame-buffered pixels onscreen, which is enough to start printf-debugging. There's still the hass...
by Bakul Shah
Wed Sep 19, 2012 8:19 pm
Forum: Other
Topic: has anyone ported Plan 9 or Inferno to RasPi?
Replies: 14
Views: 5207

Re: has anyone ported Plan 9 or Inferno to RasPi?

gwoodward wrote:Hi,

How could I get involved with the port? I was thinking of attempting a port of Inferno.
See this thread: https://groups.google.com/forum/?fromgr ... T_YFup68YU
by Bakul Shah
Wed Sep 19, 2012 8:14 pm
Forum: Other
Topic: has anyone ported Plan 9 or Inferno to RasPi?
Replies: 14
Views: 5207

Re: has anyone ported Plan 9 or Inferno to RasPi?

Bummer! I've never worked with Plan 9 before, and though that playing with a few Pi's would be a nice introduction. Any suggestions for tutorials / resources / projects to get started with Plan 9? Start here: http://www.plan9.bell-labs.com/wiki/plan9/plan_9_wiki/ A great resource is this book: Intr...
by Bakul Shah
Mon Sep 10, 2012 4:47 pm
Forum: Other
Topic: has anyone ported Plan 9 or Inferno to RasPi?
Replies: 14
Views: 5207

Re: has anyone ported Plan 9 or Inferno to RasPi?

Does anyone have a link for this port? I can't find anything but this post on the web... Would love to get plan 9 on my pi. Tomorrow at the Raspberry Jam @ the Computer History Museum in Mountain VIew, California I hope to show off 9pi -- Richard Miller's plan9 port to the RaspberryPi. This is a wo...
by Bakul Shah
Mon Aug 27, 2012 6:30 pm
Forum: Bare metal, Assembly language
Topic: GPIO Input
Replies: 13
Views: 7098

Re: GPIO Input

*Blarp* - a fast touch typist does ~120wpm on qwerty, which is 10 keypresses a second. 180wpm (15kps) or better isn't unheard of, even up to 250wpm (20+kps) in bursts. Data entry clerks generally manage ~10-15 kps on a numeric keypad. Hell, even Stephen Hawking managed 5wpm with his switch setup. Y...
by Bakul Shah
Sun Aug 26, 2012 9:58 pm
Forum: Bare metal, Assembly language
Topic: GPIO Input
Replies: 13
Views: 7098

Re: GPIO Input

You will find that its very hard to press a button for less than a second, so if you poll 2 time a second you will catch every button press. Auch! When a button press is required, I'll press the button for 200-300 ms. If I try to do it quickly, I can manage down to 50 ms (estimate). Yes there's a n...
by Bakul Shah
Sun Aug 19, 2012 8:46 pm
Forum: Other programming languages
Topic: lisp and scheme
Replies: 14
Views: 7784

Re: lisp and scheme

Getting there. Still beating my head around register allocation (I'm implementing linear scan, the theory is simple but shoehorning it into the compiler is hard - it's b0rked at the moment) so the following code does a whole load of register spilling and unspilling instead and is therefore "a bit" ...
by Bakul Shah
Fri Aug 17, 2012 6:08 pm
Forum: Other
Topic: has anyone ported Plan 9 or Inferno to RasPi?
Replies: 14
Views: 5207

Re: has anyone ported Plan 9 or Inferno to RasPi?

Tomorrow at the Raspberry Jam @ the Computer History Museum in Mountain VIew, California I hope to show off 9pi -- Richard Miller's plan9 port to the RaspberryPi. This is a work in progress -- no USB driver as yet but it boots up in seconds, uses its own fossil filesystem, can use the display and so...
by Bakul Shah
Sat Aug 11, 2012 7:07 am
Forum: Other programming languages
Topic: lisp and scheme
Replies: 14
Views: 7784

Re: lisp and scheme

This page is a great resource on Scheme implementation techniques. I should also mention Lisp in Small Pieces

Looking forward to your compiler, Simon!
by Bakul Shah
Thu Aug 02, 2012 10:31 pm
Forum: Other programming languages
Topic: lisp and scheme
Replies: 14
Views: 7784

Re: lisp and scheme

[Meant to add this to the last post but the edit window closed!] Extempore is not quite Scheme anymore. I believe there is an associated interpreted Scheme but Extempore itself is statically typed. As for a Scheme compiler, I think that for a small machine such as the raspi, Ken Thompson's approach ...
by Bakul Shah
Thu Aug 02, 2012 9:56 pm
Forum: Other programming languages
Topic: lisp and scheme
Replies: 14
Views: 7784

Re: lisp and scheme

Lots of choices here. I don't like guile but over time I have used scm (what guile is based on), gambit, ypsilon, s9, racket, chibi-scheme, ikarus, gauche etc. A number of these have an arm port. Stick to the r5rs subset and you'd be fine with most. You can also use slib (scheme library) for some co...

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