How To Reduce Linux Computer Power Consumption

Posted on in Categories GNU/Open source, Green Computing, Hardware, kernel, Linux last updated November 16, 2008

The Advanced Configuration and Power Interface (ACPI) specification is an open standard operating system-centic device configuration and power management. You can easily reduce your PC’s power consumption through smart activity monitors.

With the tools and code presented, you can reduce your power consumption through a series of rules regarding application usage. After tuning your kernel, hdparm, ACPI, and CPU settings, add these application monitors to more effectively enter your low-power states.

Understanding UNIX / Linux File System

Posted on in Categories Debian Linux, File system, FreeBSD, Linux, OpenBSD, Sys admin, Tips, UNIX last updated May 7, 2012

A conceptual understanding of file system, especially data structure and related terms will help you become a successful system administrator. I have seen many new Linux system administrator without any clue about file system. The conceptual knowledge can be applied to restore file system in an emergency situation.

FreeBSD Display Information About The System Hardware

Posted on in Categories FreeBSD, Hardware, Howto last updated January 26, 2008

FreeBSD comes with different utilities, which can be use to gathered the information as per your needs. uname command is use to print system information. dmesg command is use to print kernel ring buffer information. sysctl command is use to configure kernel parameters at runtime as well as to read hardware information.

Following list summaries, all the command you need to gather FreeBSD hardware information.

1) Determining the Hardware Type/platform:
# uname -m
2) Determining machine processor architecture:
# uname -p
3) Determining FreeBSD release level:
# uname -r
Generally, following command is use to get all info at a time:
# uname -mrs

FreeBSD 5.0-RELEASE i386

4) Determining CPU information such as speed, make etc
# dmesg | grep CPU

CPU: Pentium 4 (1716.41-MHz 686-class CPU)
acpi_cpu0:  on acpi0
acpi_cpu: CPU throttling enabled, 8 steps from 100% to 12.5%

5) Determining real and available memory to FreeBSD:
# dmesg | grep memory

real memory  = 201326592 (192 MB)
avail memory = 188555264 (179 MB) 

Alternatively, try following command to grab memory information:
# sysctl -a | grep hw.*mem
# sysctl -a | grep mem


hw.physmem: 194985984
hw.usermem: 167641088
hw.cbb.start_memory: 2281701376

Note systcl has more info, just type the sysctl command to see rest of all information:
# sysctl -a | less
6) Determining how long a system has been up:
# uptime
7) Determining when a system was last rebooted or shutdown:
# last -1 reboot
# last -1 shutdown

8) Determining swap file system usage
# swapinfo -k
9) Determining who is logged in and what they are doing. Following all commands can be used. users command displays the list of all logged in users only.
# w
# who
# users

10) Find out when user was last logged in – You can use last command as follows:
# last user-name
(a) To find out user vivek was last logged, enter:
# last vivek

See FreeBSD getsysinfo.bash script. It is use to find general FreeBSD system information such as, hostname, OS version, Kernel version, Processor/CPU, Total RAM, System load, network interface, total logged in users, Hard disks, Runlevel etc. Make sure your read the detailed installation instruction.