To obtain the operating system image, ABLE can retrieve data from a number of sources. A source may be a “block” device where data can be random accessed in discrete chunks or a “stream” device where data can be accessed serially. ABLE insulates the user from these details and provides a unified interface.
Any device, for which ABLE has a driver, can act as a source. Devices that ABLE can create sources from include ATA hard drives, ATAPI cdroms, memory devices, USB devices and network interfaces.
ABLE identifies a sources by placing the source name in brackets. Sources can be found from the ABLE command line by using the ls command on the “root” directory.
Example 6.1. Using the ls command to list available sources.
The ls when
performed on the “root” directory, with the
-a option, shows all available sources.
>ls -a -l / drwxr-xr-x 1 0 0 0 . drwxr-xr-x 1 0 0 0 .. brw-rw-rw- 1 0 0 0, 0 nor0 brw-rw-rw- 1 0 0 0, 0 hdc1 brw-rw-rw- 1 0 0 0, 0 hdc brw-rw-rw- 1 0 0 0, 0 tftpboot brw-rw-rw- 1 0 0 0, 0 xmodem brw-rw-rw- 1 0 0 0, 0 console brw-rw-rw- 1 0 0 0, 0 char4 brw-rw-rw- 1 0 0 0, 0 char3 brw-rw-rw- 1 0 0 0, 0 char2 brw-rw-rw- 1 0 0 0, 0 char1 brw-rw-rw- 1 0 0 0, 0 char0 brw-rw-rw- 1 0 0 0, 0 24cxx0p1 brw-rw-rw- 1 0 0 0, 0 24cxx0 brw-rw-rw- 1 0 0 0, 0 nand0p2 brw-rw-rw- 1 0 0 0, 0 nand0p1 brw-rw-rw- 1 0 0 0, 0 nand0 brw-rw-rw- 1 0 0 0, 0 s3c2410x lrwxrwxrwx 1 0 0 11 hd0 -> (hdc1):ext2 lrwxrwxrwx 1 0 0 5 s3c2410_serial2 -> char4 lrwxrwxrwx 1 0 0 5 s3c2410_serial1 -> char3 lrwxrwxrwx 1 0 0 5 s3c2410_serial0 -> char2 lrwxrwxrwx 1 0 0 5 u16550_serial1 -> char1 lrwxrwxrwx 1 0 0 5 u16550_serial0 -> char0 lrwxrwxrwx 1 0 0 8 nvram0 -> 24cxx0p1 lrwxrwxrwx 1 0 0 15 flash1 -> (nand0p2):jffs2 lrwxrwxrwx 1 0 0 7 flash0 -> nand0p1 >
The sources listed as links are “aliases” which build upon or “cook” the behaviour of other sources.