9. Optimization and Adjustments

There are a number of ajustments that may or may not be possible to the netBook to optimize performance of one sort or another. This section discusses the various possibilities, although many of them do not work quite yet.

9.1. Settings in /proc/

The /proc directory contains files or directories that allow various settings to be made for the netBook.

9.1.1. /proc/sys/vm/laptop_mode

If set to 1 (Set it by merely: "echo 1 > /proc/sys/vm/laptop_mode") the disks will be written to less often, apparently. What this really means for the netBook is not quite understood, but it seems like it might be a good thing to set.

9.1.2. /proc/sys/cpu/0/

Has speed, speed-max, and speed-min which represent a possible control of cpu clock speed. However, these options do not seem to be able to be adjusted at the moment. Apparently this option in /proc/... is deprecated now. In the 2.6 kernel /sysfs is used for this option, so perhaps it only works in the 2.6 kernels. The idea here is that the cpu clock speed can be adjusted on the fly to conserve energy or perhaps to overclock to maximize performance.

9.1.3. /proc/netbook/

Has many of the settings specific to the netBook, including touch screen settings as described in the section on X Windows. Those settings that can be changed, are changed by "echo VALUE > /proc/netbook/foo".

  1. battery: tells whether a battery is present or not.

  2. brightness: sets the screen brightness.

  3. contrast: sets the screen contrast.

  4. external-power: tell whether external power is present or not.

  5. flash: ???

  6. recharge: ???

  7. touchscreen: this directory has adjustments for the touch screen, as described in the X windows section.

9.2. IDE Disk Performance

The utility "hdparm" can be used to adjust IDE performance, although at present no adjustments seem to be of much help. Check out hdparm and ide performance for a complete discussion. Note that the disk access is 16 bit IO only (-c0 for hdparm) because pcmcia is 16-bit pc card. No PIO or DMA modes seem to be possible at present; this seems to be a kernel development issue. Further, pcmcia disk access (which includes the compactflash IDE card) at present uses a slower polling method, rather than IRQ's. Timing disk access using, e.g., "hdparm -tT /dev/hda", the quickest reads I've been able to achieve are around 2 MB/s. "hdparm -u1 /dev/hda" might be helpful.

You can check the current various settings for your disk by executing "cat /proc/ide/hda/settings."

9.3. System and Hardware Clocks

Apparently these clocks are different, and the EPOC system could potentially access the hardware clock. However, reboots seem to set the hardware clock back to 1971. "hwclock --systohc" will set the system clock to the hardware clock.