Skywave Linux to USB / SD Media
UPDATED 5/17/2019: Changes to conventional installer method.
Skywave Linux is a fast and lightweight operating system, based on Ubuntu, and distributed as a live CD iso file. While a few users prefer to run it directly from a CD, most will use one of the methods described below to put it on a USB or SD memory device for easy portability. Users certainly should seek the higher performance of a system installed to a SSD or flash drive!
Option 1: Standard Installation (Decompressed)
Skywave Linux may be installed as a conventional Linux system using either the "Ubiquity or "Calamares packages. Either one will install your running system as a regular, non-iso-based Linux system. Here is an example of code to run in the terminal:
sudo apt update sudo apt install ubiquity
sudo apt update sudo apt install calamares
After installing, open the menu and click the apropriate launcher. Use caution and select the proper drive and make sure the bootloader is installed to the root of the device if it has multiple partitions. There is one exception to the practice of installing Grub to the root of the drive: if installing multiple systems to a device, install Grub to the partition containing the new system and "chainload" to it.
Option 2: Copy the Disc Contents (Compressed)
It doesn't get easier than this. Ubuntu based Linux distros now contain a utility called "USB Image Writer" specifically created for installing systems from iso files. Universal USB Installer, YUMI, and Unetbootin are other applications which will also write an iso file's contents to a flashdrive and make it bootable.
A good reason to use these applications is that they keep the system in its compressed format, using up much less space than a standard decompressed installation. In addition, it is possible to set up another partition for persistence - keeping changes and files across shutdowns and reboots.
Option 3: Write the Image Directly (Compressed)
For this easy iso direct-to-USB/SD method, we will use the Linux dd command, which comes with virtually all distros, including Skywave Linux itself. You can use Ubuntu, Debian, Mint, Knoppix, Puppy, Arch, or just about any derivative to write the iso file contents directly to a flash memory device. There is one factor to consider, though: using dd overwrites everything and allows only the iso's contents to remain on the flash memory device. Do not use this technique for a multipurpose device. Pick a flashdrive or SD card that exceeds the size of the iso: 2.0 GB is enough for Skywave linux.
- A running Linux system such as Debian, Ubuntu, Arch, Knoppix, Mint, or Skywave Linux.
- A USB or SD flash memory device just slightly larger than the iso file (2 GB is sufficient)
- A Skywave Linux ISO file. Get Skywave Linux from here.
The dd utility comes from early Unix, and survives to this day as an essential command to copy data, bit for bit, to another location. It does not discriminate and simply does what it is told. The dd command is used for backing up the boot sectors of hard drives, completely copying storage devices for forensic analysis, or making backups. For making bootable flasdrive linux devices, dd is perfect.
Be careful with dd! It can overwrite important data if diven incorrect commands!
To use dd for creating a bootable USB or SD Skywave Linux system, you must properly identify the iso file and the destination drive.
Knowing where to find the iso is easy: simply note the folder and filename path where Skywave Linux is residing on the computer. Usually it is in the "downloads directory, such as:
The destination directory is much more critical, because dd must not be directed to write in an unwanted location. More than a few people have destroyed data on their hard drives or other storage by accidentally using the wrong identifier for a dd job. Properly dentify the device where you want to put Skywave Linux and all will go smoothly! Note that we want the device and not partitions on a device. A good technique is to look at the output from the "fdisk" command. The "lsblk" command also works, but is a bit less verbose than "fdisk -l". In the example, the main hard drive is /dev/sda and the USB flash drive is identified as /dev/sdb:
winston@churchill01:~$ sudo fdisk -l Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd9c2816e Device Boot Start End Blocks Id System /dev/sda1 * 63 43761059 21880498+ 83 Linux /dev/sda2 43761060 357703289 156971115 83 Linux /dev/sda3 357703290 616735349 129516030 83 Linux /dev/sda4 616735350 625137344 4200997+ 82 Linux swap / Solaris Disk /dev/sdb: 3965 MB, 3965190144 bytes 49 heads, 48 sectors/track, 3292 cylinders, total 7744512 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x1d187107 Device Boot Start End Blocks Id System /dev/sdb1 8192 7744511 3868160 b W95 FAT32
With the parameters properly identified, it is now possible to write and execute a proper dd command. Some distros have tighter restrictions on normal users, so execute this as root (using "sudo" is okay):
dd if=/home/winston/Downloads/skywavelinux-1.4.iso of=/dev/sdb bs=1M
Results should look similar to the output below, which was from a test run of this method of creating bootable SD card from Skywave Linux:
root@churchill01:/home/winston# dd if=/home/winston/Downloads/skywavelinux-1.4.iso of=/dev/sdb bs=1M 1603+1 records in 1603+1 records out 1632307712 bytes (1632 MB) copied, 354.782 s, 4.6 MB/s
To boot the newly installed system on a USB device, go into the computer's BIOS options and set them to boot from the flashdrive first, and make the system hard drive the next choice. Often the USB device appears listed as one of the hard drives and not as a removable device. Good luck, and enjoy the convenience of having Skywave Linux installed to a flash memory device. It is an order of magnitude faster than running from a DVD. If you want to put Skywave Linux on a multi-system USB device, or on the main hard drive, see the contents above for a link to the article on installing and booting multiple systems with Grub2.
Tags:HPSDR, GHPSDR3, RTL-SDR, Cubic SDR, SDR Software, Ubuntu, Linux SDR, Skywave Linux USB stick, Skywave Linux SD card, Skywave Linux in your pocket