There are people who let their home PC run through for years, without ever deliberately turning it off. Like an office PC, the home computer should also be able to be active immediately, if necessary, and can carry out various background jobs, such as backups or smaller server services. And who does not know them?
Office variant
The terrible slowdown after Microsoft has humankind humankind with new updates and hotfixes? To avoid all this slowness and the resulting limitations, you could simply leave the PC switched on and do without current power functions. In terms of performance! The realization that this is very practical, but not exactly economically reasonable, comes after a comparison of the average energy consumption with friends and acquaintances. There are obviously big differences, most likely very large differences.
Lightwax apples
Suppose the PC consumes about 150 watts of power during operation. That means that it consumes 1 KW of energy in 06:36 hours. The consumption is roughly rounded to 4 KW per day. The monthly cost of a PC running around the clock 30 days (4KW x 30 days x 0.265 Euro electricity costs per KW): 31,80 Euro. A lot of money when you consider the actual net usage time.
Wake on LAN
In addition, there are many components that run alongside the PC. Monitor, switches, speakers, possibly the printer. It adds up. If you need more than one PC for your work or hobby, you will be able to "enjoy" a correspondingly high power calculation. The costs for a computer running around the clock add up to a substantial amount of almost 400 euros for a year. Not to mention the negative environmental impact of a senseless PC.
WOL a la Internet
There must nevertheless be possibilities to activate the PC system in a targeted way, to keep the current costs in mind and at the same time to enjoy the advantages of a prepared PC system! And yes, there are different possibilities. For a proper interaction, it is always recommended to use a master-slave socket strip. In the case of these multiple sockets, a relay switches off all sockets designated as slaves, provided that the slot designated as master does not refer to at least one freely adjustable quantity of energy.
Typically, the computer is connected to the master slot, speakers, monitor, printer, scanner, and all other peripheral devices to the slave slots. If the operating system switches to the idle mode (referred to as S3, S4 or S5 in the BIOS), the power consumption drops so much that the adjustable threshold value for the slave slots is undershot, and the multi-socket power strip switches these devices off. The PC that remains idle will remain at a very low power consumption.
The classic variant for the automated active PC is the office. Anyone who typically runs his office in the office from Monday to Friday at 8 o'clock will have easy access to his PC. Many modern BIOSe, for example in the Optiplex or Precision series from Dell computer, have the right function for this. The user can set exactly when the PC should automatically switch on. The already mentioned master-slave socket ensures that all components and peripherals are also ready for use. Unfortunately, the BIOS, which is quite powerful in itself, only has the Disable, Every Day and Weekdays setting.
It would be better to have a system that is distinguishable every working day, in order to plan different working hours, for example, or to give the patch Tuesday more time. Not infrequently, Microsoft's update tag needs an automatic restart, which the user could schedule right away. The BIOS switch-on is very convenient, does not cost any money and does not need any other devices. The fact that the coffee machine is connected via a slave slot and also the hot drink is on time, but is rather what the brave computer geeks.
Time-controlled switching on and off has long been a good sound for Mac computers. Since the introduction of OS X, Apple users have been able to determine when the Mac should turn on or off automatically in the system settings. Planned reboots are also possible, as is the selection of a time window.
Unfortunately, the same limitations as the BIOS possibilities of standard PCs are available with the Mac: The user can not create different starting times on different workdays. In the same setting window, where the user can define the time after which a rest state may occur, there are other important customization options.
Under Options, the Mac owner determines whether the device is to be switched on after a power failure and whether the computer is to wake up for administrative Ethernet network access. Behind this almost lyrical description is Wake On Lan (WOL) - probably the most important technique when it comes to automatic switching on the network. But beware - the Mac starts, if it is prompted by WOL, only when it is in a state of rest. Off, the Mac does not respond to the wake-up signal, like most other PCs.
The times when a large, chunky switch on the back of the PC mechanically separated the power supply have been over for more than two decades. Already in 1995, the companies Hewlett Packard and AMD defined a proposal for a standard to ensure that a switched off computer can be switched on again via the built-in network card. How this works exactly, AMD in a white paper from the year 1995 with the number 20213 on six sides.
In a nutshell, the BIOS uses the APM (Advanced Power Management) or the Advanced Configuration and Power Interface (ACPI) via the standby current branch of the power supply, which is still active when the PC is switched off interpret. Typically, this data packet is called a Magic Packet - a trademark of AMD. The packet itself consists of the hexadecimal value FF six times in succession, followed by a 16-time repetition of the MAC address of the network card. The Magic Packet is sent via UDP. WOL uses the MAC address and not the IP address. The IP address would also be a bad choice, given the spread of DHCP servers and the upcoming introduction of IPv6 technology.
And without WOL?
In order to really benefit from WOL, the user needs the right software. WOL tools are available in abundance, for all possible operating systems. Good solutions differ from the many rather simple programs in that they allow the resolution of the MAC address to a NetBIOS name or an IP address. Otherwise, the IT professional is forced to type the MAC addresses by hand. While this is not a witchcraft, it is just more cumbersome and less accustomed to using IP addresses and names.
We would like to point out the program Wake On Lan 2, the newly developed successor of the Wake On LAN Tool Classic. WOL2 was programmed in C # and is based on the .NET framework and the MONO 2.0 framework. This technical basis gives the small free program of Marko Oett e both for Microsoft Windows as well as for Linux and OS X. WOL2 organizes the Gerätelisten in storable files and allows the search for the desired settings. If a known value, for example the hostname, the IP address or the MAC address, is entered in the New Host dialog box, the program determines the other values by clicking the Resolve button. The beauty of the program is the other functions that the author has given on the way. The user can also choose to download selected systems as a package as long as the targets support the technology.
RDP-, PING-, PuTTY- or VNC-accesses, directly via the list selection, round off a total positive overall picture. At rest, most of the current computers work with WOL, while in the switched off state a large number, but not all PCs. A look into the BIOS, as well as the settings for the network card, provide information on whether all prerequisites for a targeted wake-up are fulfilled. The entry is usually found under Wake On LAN or Power Up On PCI Card. If the network card still holds the link to the switch when it is switched off, as well as the LED on the NIC, the chances are good. To ensure that an intermittent power failure does not prevent the packet from being received, the BIOS setting is recommended to turn on the PC after a power failure.
Anyone wishing to wake up their computer via WOL over the Internet is faced with the problem that an off-screen computer no longer responds to its IP address. As a result, only the WOL functionality remains broadcast. Internet connections, however, do not transmit broadcasts to private networks.
In cooperation with a router port forwarding, the Otto von Guericke University in Magdeburg offers a highly recommended guide and the appropriate Wake Up command on the homepage of the Faculty of Electrical Engineering and Information Technology. Whether this technique can be used depends entirely on the router used. Of course, AVM, the stalker on the American DSL router market, has installed a wake-on-LAN function in its Fritzbox series. If the PC, a server or a NAS WOL offers, then the Fritz box can provide for an awakening over the Internet, as long as the connection between WOL device and the box over an Ethernet cable exists
Practically, the developers use AVM in the case that resources can also be accessed via the Internet. The target systems are awakened from a resting state as soon as the box directs the first data packets to them. Conditions for a functioning device are furthermore the most recent firmware and the allocation of a public IPv4 address via the provider. If the Fritzbox is another router, the construction will generally fail. If, for example, the user wants to set up RDP access to a Windows PC via the Fritzbox, he selects the desired computer and port 3389 on the box under Port release.
In the Home network category in the Network subcategory in the Devices and Users tab, select the desired computer and select the "Automatically start this computer as soon as it is accessed from the Internet."
WOL is indeed an extremely practical thing and therefore a standard. What if it is about switching on or off devices that do not react to WOL at all? Expensive server systems, which most readers know, have a remote management adapter. Thus, server systems are accessible even if the operating system on them does not react to commands at all.
For smaller environments or the home network, such techniques are often far too expensive and complex. There are also a variety of systems that you would like to switch, which are actually no computers at all and therefore can never work with WOL. Small network sockets, such as the ALL3073 from Allnet, are suitable for these applications. Via an integrated web server, which is addressed by the user via 10/100 MBit Ethernet or via 802.11 b / g / n, it is possible to switch a connected consumer. The user assigns the switching processes either manually, if required or programmed in a timed manner.
The ALL3073 also comes with a kind of built-in watchdog. With the server monitoring function, the IT-Pro_ ensures that any IP device is monitored by a regular PING command. If the system does not respond in a given time, the current output is switched off and switched on again for a time which can also be set. A summary with several network sockets of type 3073 and 3075v2 can be implemented via the function of the actuators. Apart from these many additional features, the Web Interface is primarily composed of a large switch that turns on the power supply.
What the user has to remember, however: If the interface shows the Schuko connection symbolically in red color, then current is applied. No current flows in green. It might have been useful to include the information as text on the website.
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