To enter the power saving mode, you can use the appropriate commands of operating system, special buttons on a keyboard or the Power button on a system unit.
To define the time before switching to the power saving mode by using BIOS tools, use the parameter “Power Management”. This parameter may have the following values: User Define – the time is defined by a user; Max Saving – a mode of maximum power saving during which a computer switches to the low power mode in 10-30 seconds; Min Saving – a mode of minimal power saving during which a computer switches to the low power mode in 40 minutes; Disable – the power saving mode is disabled. As a rule, a value “Max Saving” is used by default for this parameter but an optimal value for this parameter is “User Define”.
You can use the parameter “Doze Mode” to define the time after which your computer will be switched to the low power mode by using BIOS tools. This parameter may have the following values: time intervals (in minutes) and Disabled.
In addition to the parameters that enable switching on/off the power saving mode, as a rule, there is a set of parameters that enable to control the switching-off of some individual components: hard disks, monitor and processor.
The computers with old AT form-factors can be switched off by pressing the flush Power button on the front panel of the system unit. The ATX-units are equipped with a push button. A system may ignore a single clicking on a power button. BIOS is able to solve this problem.
The parameter “Power Button Function” (Power Button Mode) controls the system behavior while pressing the Power Off Button. This parameter may have two values: On/Off – a computer is turned on/off when the trigger is clicked; Suspend – if a computer is on, the trigger activates the power saving mode, and if pressing the button for more than 4 seconds, a system is turned off. The type of the triggered power-saving mode depends on a value set for the parameter “ACPI Suspend Mode”.
In addition to the parameter “Power Button Function”, the following parameters have similar functions for controlling the power On/Off:
- The parameter “Power Button Over Ride” has got two values: Enabled – to switch off the power it is allowed to use the software tools of operating system while mechanical switch-off is achieved only after holding the power button for more than 4 seconds; Disabled – a computer switch-off is achieved by clicking the trigger.
- The parameter “Power-off by PWR-BTTN” (Soft-Off by PWRBTTN) has got two values: Hold 4 Sec (Delay 4 Sec) – when pressing the trigger, the system goes into the power saving mode, and when holding the Power button for more than 4 seconds, the system switches off; Instant-Off – an instant computer shutdown when triggering.
- The parameter “PWR Button < 4 Secs” has got three values: Soft Off – the software tools are available for entering the power saving mode, and a computer is switched on after pressing the power button; Suspend – after pressing the power button, a system enters the power saving mode, and while holding the button for more than 4 seconds, a computer is switched off; No Function – all power-saving mode functions are switched off and the power button operates as a common on/off button.
The hibernate mode is characterized by a complete power disconnection. But before switching off, the whole content of operating memory is copied on the hard disk. During the next launching, a system automatically restores the operation from the position of the last stoppage by rewriting the stored information from the hard disk into an operating memory. For example, if you are downloading some information from the Internet using standard Windows tools and your computer goes to the hibernate mode, the downloading will be continued after the system recovery.
To select the power control mode, use the parameter “ACPPI Suspend Type” (ACPI Standby state) which may have two values: S1 (POS) – the Power On Suspend Mode is on; and S3 (STR) – the Suspend to RAM Mode is on. If a value S1 is on, only the Suspend mode will be available for your computer, and a value S3 is on – both the Suspend and Hibernate modes will be available. But if you use Windows98 that does not support the opportunity to save operating memory on the hard disk, the Hibernate Mode may still be unavailable. To use such mode, your system should have the ability to fuel memory with the information about a system state.
To get to the power saving mode, use the parameter “Suspend-to-RAM Capability” which may have three values: Enabled, Disabled and Auto.
A computer may operate in four modes: On, Off, Standby and Hibernate. The first two modes are available to any normally functioning computer, the standby mode is activated if the APM standard is connected, and hibernate mode is available to portable computers (notebooks) with Windows XP/2000 only in the ACPI mode. Besides, in case of a particular signal, the suspend mode and low frequency mode (doze) can be automatically set, allowing the working capacity to be restored.
What is the difference between the standby and hibernate modes? All computer devices, except memory, are disconnected or go to the power saving mode in the standby mode. A monitor also “sleeps”. But all fans on a processor and in the power supply are still working. This allows returning a computer into its normal state either by pressing any button on a keyboard (mouse moving) or in case of some system event, for example when retrieving e-mail.
In addition, some failures may arise after switching on the expanded power-saving mode. For example, your computer may be spontaneously switched on again. To control automatic switching, use the parameter “State After Power Failure” (AC PWR Loss Restart, AC Back Function). This function has the following sequence of steps: when the power is switched off, the computer’s state is fixed, and as soon as the supply voltage reaches normal values, a computer may be switched on. This parameter may have three values: Yes (Enabled), No (Disabled) and Auto. When this parameter is on, your computer will be automatically switched on if during the voltage drop it was operating. Moreover, some motherboards have the following effect: as soon as the voltage increases, your machine will turn on itself.
It is recommended to set the value “Off” for the home PC. In this case, a computer remains switched off after the restoration of power supply. The value “Auto” enables to return to the state that was at the moment of power voltage disappearance.
All modern computers are based on ACPI standard. This standard is used to configure and adjust an operation of the hardware – to assign interruptions and resources to the devices on PCI and AGP buses, to receive information about devices and for operation of additional “power-saving” buttons and sensors and other.
For example, a motherboard is able to support APCI standard while BIOS is incompatible with it. This situation is very real because motherboards are long-term manufactured using this standard but BIOS had recently used it. And only reflashing may help in this situation.
To switch ACPI standard on, use the parameter “ACPI Function” (IPCA Function) which is located in a section “Power Management Setup” (Power or Power Management Futures). This parameter may have two values: Enabled and Disabled. If this standard is enabled, the control over the expanded power control can be given to operating system. To do this, you may use the parameter “PM Control by APM” (Power Management/APM). This parameter may also have two values: Yes and No. If this parameter is enabled, some settings for other parameters (for example, Suspend Mode, HDD Power Down or similar to them) will be ignored in BIOS because, in this case, the control over the power was given to operating system. This parameter should be switched on only for Windows98 and the higher version.
In the mid-1990-s all computers were produced according to the Energy Star standard which indicated the availability of the energy saving functions. This standard has been jointly developed by Microsoft and Intel Companies and its logo is on all brand computers, monitors, printers and other peripheral internal and external devices which meet the set values on power saving. At around the same time, the parameters of power management “Advanced Power Management” (APM) were added to BIOS. These parameters offered a broad range of possibilities that, unfortunately, in most cases have not been in use because of poor-quality processing in these operating systems.
The further development of APM was “Advanced Configuration and Power Interface” (ACPI) that has been jointly developed by Intel, Toshiba and Microsoft Companies. This standard had been integrated into Windows98. As a result, we have a manager which not only controls the power but enables to control the entire system. Here are some opportunities of ACPI standard:
- Monitoring the system Events. A system that uses this standard enables to respond flexibly to changes in power consumption or the temperature of a processor or an air inside the case, to control the turning of system devices on/off.
- System Power Management. A system is automatically or forcibly able to access the lower levels of power consumption until a complete power disconnection with the further restoration of working capacity.
- Processor Power Management. A system is automatically able to switch off a processor during the down time. This has favorable impacts on the processor’s resource productivity.
- Device Power Management. A system is able to control and reallocate the modes of power consumption depending on the requirements of a system, the software and a user.
- Thermal Management. A system enables to monitor the temperature in different devices (in most cases, a processor or a system unit) using special sensors.
Use the parameter “IDE HDD Block Mode” (IDE HDD Block Mode Sectors, Multi-Sector Transfers) which enables to appoint BIOS as a distributor of structure blocks on the hard disk. This parameter has got the following two values: Enabled (HDD Max, Maximum) and Disabled. If the hard disk supports a mode of block data exchange (block transfer, multiple commands or multiple-sector read-write), this parameter allows BIOS automatically determining the best block size of the hard disk and controlling this value when reading or writing the data. When exchanging the data, several sectors will be simultaneously read and written that significantly increases an operating speed. If the hard disk does not support the multi-sector operating mode, this parameter must have a value “Disabled”. In this case all data will be read and transmitted to a system sector-by-sector.
You can also use the parameter “Multiple Sector Setting” which allows manually adjusting an amount of sectors in a block. This parameter may have the following values: Auto Detected, 2 sec/block; 4 sec/block; 8 sec/block; 16 sec/block, 32 sec/block and Disabled.
Another parameter that may cause the increasing in the hard disk efficiency is “IDE Perfect Mode”. Using this parameter, you can enable the use of buffers of data storage. If this parameter is switched on (Enabled), the speed of data exchange between a disk and controller will be increased. But if there are some failures, this parameter should be switched off (Disabled).
The easiest way to gain better speed is to overclock a processor using a system bus that automatically causes the increasing in frequency of PCI-bus. This procedure may lead to the increased speed while data exchange only to some limits. For example, if the frequency of PCI-bus is higher than 37-40 MHz (a standard frequency is 33 MHz), there may be some failures because the transmitted and incoming data have no time for processing. As a result, some part or even the entire information on the hard disk may be lost. At the same time, the hard disk itself is not affected, except the increased heat.
Another way to increase the speed of reading/writing is using the readahead systems which are nowadays implemented at the hardware level. In this case, if there is some request from the controller for reading a particular sector of the hard disk, not only the requested data block but also the next one are read into its cache. Some hard disks are able to monitor the most commonly-used memory sectors and store some data in a cache, thus optimizing and speeding an access to them.
If there is no hardware support of multi-sector reading and writing, it is possible to use some BIOS settings. But you can use BIOS only if you operate with some outdated operating systems that use the following file systems: FAT, FAT16 and FAT32. If you operate with Windows NT/2000/XP, the usage of BIOS parameters may result in the loss of some information of the hard disk.
The main parameters in the selection of the hard disk are its volume, speed of reading-writing and searching time. It is clear that the higher the disk volume and the higher the speed of searching and exchanging information, the higher the disk productivity. BIOS cannot impact the amount of stored information but it can impact the speed of exchange.
Nowadays most of the hard disks, except the outdated ones, are equipped with internal clipboard, or cache, that enables to exchange data more effectively. All procedures of buffering are implemented at the hardware level, so it is possible to optimize an access to reading-writing only by the IDE-controller. For example, you can significantly speed-up the reading-writing processes of IDE-interface by using the parameter “IDE Data Post Write” (IDE Fast Post Write). This parameter has two values: Enabled and Disabled. To receive the required result while reading-writing, this parameter should be switched on. But it may cause some failures when the IDE-interface has no posted-write buffer. In this case this parameter should be switched off (Disabled).
The speed of implemented procedure plays an important role when reading-writing to a disk. It contains a mechanical component – the speed of disk rotation and the time spent of positioning of reading heads, and an electronic component – the time of data exchange between the disk and controller and also between the controller and operating memory. The mechanical component is invariable while the electronic one can be adjusted to gain better speed.