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Friday, June 1, 2012

First Impressions of Raspberry Pi

Well a Raspberry Pi arrived in the post today:



These are my first impressions after using it for less than an hour.


Summary


Pros:

Easy to get up and running, no uboot type issues, Debian SD card image works well, comes with LXDE which feels fast, network works out of the box.  Image includes a 3.1.9 kernel.

Sample Debian image is really well designed

Cons:

No obvious serial connection.
Default Debian image needs to be resized for but has a swapfile as the last partition. Easy to fix though.
 
Background:

I used Ubuntu 12.04 on my development PC to load the image. I powered the
board using the phone charger for my Samsung Galaxy phone. I booted with wired Ethernet connected via a switch to a router. I connected to an LCD monitor using an HDMI to DVI-D cable. My mouse and keyboard were attached via a USB hub.  



Steps I took to set up my Raspberry Pi ("Raspi").

1) Took it out of packaging and inspected it for defects etc.  No problems visible.

2) Went to http://www.raspberrypi.org/downloads and downloaded the Debian image.

3) I used Ubuntu to load the image on an SD card. Followed the website above's directions on using dd to copy the image. I issued the command "sync" after dd finished.

4) Unmounted the SD card and placed it in the Raspi.

5) Connected all cables, connecting power last.



6) Monitored the screen and saw fairly instant response showing the Debian booting.

7) Logged in using the default username and password (u:pi    p:raspberry   - see the link above).


8) Installed "htop" using apt-get with the command:

 sudo apt-get install htop

9) Started a GUI with "startx"

All the steps above worked well and quickly

I then decided to resize the filesystem on the SD card.

I shutdown the Raspi and put the SD card back into my development PC and ran "gparted" as root.  This is how the SD card is formatted by default:



I deleted the swap partition and resized the ext4 to fill the full available space on the card.  It now looks like:


I will go back and set up an actual file in the system as the swap space accessible to Debian.  The advantage of doing this is that I can resize the swapfile from the terminal without touching the partitions.

I'll cover how to do this in a separate post.

Note the Raspi will boot without any swap space, it just might have issues if you run large processes like apt-get.

The shot below shows htop running after booting without any swap space:




Note:

Always use a brand name SDCard. No matter what system (Beagleboard, PandaBoard etc) I've had no end of issues with generic cards.  They don't appear to be of any worth whatsoever when you need it to hold an OS.


Feel free to leave any questions queries in the comments below.

1 comment:

Dingo_aus said...

Quick and dirty commands to set up a swapfile:

sudo mkdir -p /var/cache/swap/
sudo dd if=/dev/zero of=/var/cache/swap/swapfile bs=1M count=1024
sudo chmod 0600 /var/cache/swap/swapfile
sudo mkswap /var/cache/swap/swapfile
sudo swapon /var/cache/swap/swapfile