TS-4710 Initrd / Busybox

From embeddedTS Manuals
Revision as of 11:05, 22 April 2013 by Mark (talk | contribs)

When the board first boots up you should have a console such as:

>> TS-BOOTROM - built Jan 21 2013 16:17:55
>> Copyright (c) 2012, Technologic Systems
.
.
Uncompressing Linux... done, booting the kernel.
Booted in 0.67 s
Type 'tshelp' for help

This is a minimalistic initial ram filesystem that includes our specific utilities for the board, and is then used to bootstrap the Linux root. The initramfs is built into the kernel image so it cannot be modified without rebuilding the kernel, but it does include 8 bits for common configuration option we call soft jumpers.

Soft Jumpers
Jumper Function
1 Boot automatically to Debian [1]
2 Baseboard Specific
3 Baseboard Specific
4 Read Only mode [2]
5 Disable Network Autoconfiguration
6 Reserved
7 Reserved
8 Skip full DRAM test on startup [3]
  1. initramfs boot is default
  2. The read only mode creates a unionfs where the full Linux root is mounted read only, and a tmpfs is mounted read/write. This allows services to run that require write access, but doesn't commit any changes to disk. This can be used to protect your application from corruption caused by sudden poweroffs.
  3. The DRAM test can be used to verify the RAM, but adds approximately 20 seconds to the boot time. This should normally only be enabled when diagnosing problems.

There are 2 ways to manipulate soft jumpers on the board. The web interface at "http://ts4710-<last 6 chars of the MAC" has a list of checkboxes that will immediately change the values. You can also use tshwctl:

# Boot automatically to Debian:
tshwctl --setjp=1

# Or revert to the initramfs:
tshwctl --removejp=1