preparing the sd card
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Introduction
This section explains how to install the runtime environment required to run RTCs for Raspberry Pi (hereafter referred to as RPI RTCs).
The following installation procedure assumes a Windows environment. If you are using an environment other than Windows, refer to sites such as the following.
This section explains how to download an OS image from the official Raspberry Pi website and perform the required setup. The general procedure for using OpenRTM on Raspberry Pi is as follows.
- Write the OS image to an SD card
- Perform basic OS setup
- Install OpenRTM-aist
- Test component execution
Images with OpenRTM-aist and the Kobuki component already installed are also provided below, so the following steps can be skipped.
- OpenRTM-aist installation (not yet available)
- Kobuki component installation (not yet available)
- PiRT-Unit setup (not yet available)
SD Card Capacity
The SD card used must be at least 2 GB, but in actual use, 4 GB or more is required. Be sure to prepare an SD card of 4 GB or larger.
Downloading the Image
Download the Raspberry Pi OS, Raspbian “wheezy,” from the following site. Raspbian is a Debian-based Linux distribution for Raspberry Pi.
- Raspbian Wheezy: http://www.raspberrypi.org/downloads
Extract the downloaded file YYYY-MM-DD-wheezy-raspbian.zip.
A file of about 2 GB named YYYY-MM-DD-wheezy-raspbian.img should be extracted.
$ ls -al
total 4752840
drwxr-xr-x 4 n-ando staff 136 5 18 13:30 .
drwxr-xr-x 9 n-ando staff 306 5 18 13:30 ..
-rw-r--r-- 1 n-ando staff 1939865600 2 9 12:44 2013-02-09-wheezy-raspbian.img
-rwxr-xr-x 1 n-ando staff 493587826 5 7 21:08 2013-02-09-wheezy-raspbian.zip
If extraction fails, the download may have failed and the file may be corrupted. Delete the corrupted file and download it again.
Writing the Image
The extracted yyyy-mm-dd-wheezy-raspbian.img is called an image file. It contains the complete disk state required to boot Raspbian, copied byte by byte from the beginning to the end of the disk.
Simply copying this file to the SD card will not work!!;
Write it to the SD card using the method described below.
Writing the Image (Windows)
On Windows, the image can be written using a tool called Win32DiskImager. Download the Win32DiskImager binary from the following site.
- Win32DiskImager: http://sourceforge.jp/projects/sfnet_win32diskimager/
Extract the downloaded file (win32diskimager-vX.X-binary.zip).
* Win32DiskImager does not support double-byte characters, so extract YYYY-MM-DD-wheezy-raspbian.zip to a location where the path does not contain full-width characters or spaces.;
Insert the SD card to be used with Raspberry Pi into the PC, and start Win32DiskImager.
* The SD card must be recognized as a drive, so format it in FAT32 format beforehand.;
Specify the extracted Raspbian image file (YYYY-MM-DD-wheezy-raspbian.img) in “Image File,” specify the SD card drive in “Drive,” and click the “Write” button.
This completes the preparation of the SD card. After writing is complete, insert the SD card into the Raspberry Pi and turn on the power.
Writing the Image (Linux)
On Linux, images can be read and written using the dd command.
The dd command is usually installed by default on UNIX-like operating systems.
After inserting the SD card, check the kernel messages using the dmesg command.
$ dmesg
: Omitted
[333478.822170] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[333478.822174] sdb: sdb1 sdb2
[333478.839563] sd 3:0:0:0: [sdb] Assuming drive cache: write through
[333478.839567] sd 3:0:0:0: [sdb] Attached SCSI removable disk
[333479.094873] EXT4-fs (sdb2): mounted filesystem with ordered data mode
[333527.658195] usb 1-1: USB disconnect, address 2
Check the SD card device name from this message. In this example, sdb appears to be the SD card device name. Check under /dev/.
ls -al /dev/sd*
brw-rw---- 1 root disk 8, 0 May 7 17:28 /dev/sda
brw-rw---- 1 root disk 8, 1 May 7 17:28 /dev/sda1
brw-rw---- 1 root disk 8, 2 May 7 17:28 /dev/sda2
brw-rw---- 1 root disk 8, 5 May 7 17:28 /dev/sda5
brw-rw---- 1 root disk 8, 16 May 18 14:19 /dev/sdb
brw-rw---- 1 root disk 8, 17 May 18 14:19 /dev/sdb1
brw-rw---- 1 root disk 8, 32 May 18 14:19 /dev/sdc
sda is usually the system disk, so you must never touch it.
Depending on the distribution, if the SD card contains a mountable filesystem, it may be mounted automatically.
In that case, unmount the disk. (On Ubuntu, the mounted filesystem folder appears on the desktop, so right-click it and remove it. On other systems, unmount it using the umount command.)
Enter and execute a command in the form dd if=image file of=SD card device file bs=1M.
Writing to a device file requires administrator (root) privileges, so use sudo.
$ unzip 2013-02-09-wheezy-raspbian.zip
Archive: 2013-02-09-wheezy-raspbian.zip
inflating: 2013-02-09-wheezy-raspbian.img
$ sudo dd if=2013-02-09-wheezy-raspbian.img of=/dev/sdb bs=1M
1850+0 records in
1850+0 records out
1939865600 bytes (1.9 GB) copied, 201.543 s, 9.6 MB/s
While the command is running, you can check whether writing is proceeding correctly by running the iostat command in another terminal.
(On recent distributions, it may not be installed by default. On Debian/Ubuntu, you can use the iostat command by running apt-get install sysstat.)
$ iostat -mx 1
avg-cpu: %user %nice %system %iowait %steal %idle
0.00 0.00 0.00 50.25 0.00 49.75
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 1.00 0.00 0.00 8.00 0.00 0.00 0.00 0.00
sdb 0.00 1856.00 0.00 78.00 0.00 9.14 240.00 143.40 1855.85 12.82 100.00
Looking at the sdb entry, you can see that data is being written at 9.14 MB/s.
If a class 6 SD card writes at around 6 MB/sec, or a class 10 SD card writes at around 10 MB/sec, it is reasonable to assume the write is proceeding normally.
After writing is complete, some distributions may automatically mount the SD card again. In that case, unmount it before removing the SD card.
Writing the Image (Mac OS X)
On Mac OS X, as with Linux, the dd command is used to write the image.
However, on Mac, when an SD card is inserted it is automatically mounted, and while it is mounted, dd cannot write to the SD card. Therefore, it must be unmounted (removed from the OS).
When the SD card is inserted, an SD card icon appears in Finder as shown below. Be careful not to press the eject button when you intend only to unmount it for writing.
In this example, the SD card volume name is Untitled. Remember this volume name.
Entering the df command from the command prompt displays the following.
$ df -k
Filesystem 1024-blocks Used Available Capacity iused ifree %iused Mounted on
/dev/disk0s2 500000000 437664508 62079492 88% 109480125 15519873 88% /
devfs 194 194 0 100% 679 0 100% /dev
map -hosts 0 0 0 100% 0 0 100% /net
map auto_home 0 0 0 100% 0 0 100% /home
/dev/disk1s1 57288 18992 38296 34% 512 0 100% /Volumes/Untitled
The bottom entry, `/Volumes/Untitled`, is the mount point of the SD card. Remember the device name on the far left, `/dev/disk1s1`.
Unmount this SD card temporarily. Use the diskutil command and enter it in the form **diskutil umount
$ diskutil umount /Volumes/Untitled
Volume (null) on disk1s1 unmounted
$ df -k
Filesystem 1024-blocks Used Available Capacity iused ifree %iused Mounted on
/dev/disk0s2 500000000 437664716 62079284 88% 109480177 15519821 88% /
devfs 194 194 0 100% 679 0 100% /dev
map -hosts 0 0 0 100% 0 0 100% /net
map auto_home 0 0 0 100% 0 0 100% /home
The previous /Volumes/Untitled entry has disappeared, showing that the SD card has been unmounted.
Next, use the dd command to write the image.
Enter it in the form dd if=image file of=/dev/rdisk1 bs=1m.
The of=/dev/rdisk1 device name is created from the device file remembered earlier, /dev/disk1s1, by removing the trailing s1 and adding r before disk to indicate that it is a raw device.
This command accesses the device file, so it cannot be executed unless you have administrator (root) privileges. Use sudo as follows.
$ sudo dd if=2013-02-09-wheezy-raspbian.img of=/dev/rdisk1 bs=1m
1850+0 records in
1850+0 records out
1939865600 bytes transferred in 302.377337 secs (6415380 bytes/sec)
$
During writing, you can check whether writing is proceeding correctly by viewing “Disk Activity” in Activity Monitor. If a class 6 SD card writes at around 6 MB/sec, or a class 10 SD card writes at around 10 MB/sec, it is reasonable to assume the write is proceeding normally.
When writing is complete, the card will automatically be mounted again. This time, press the eject button in Finder and remove the SD card.