OS: Thrashing

在電腦的知識範疇中，談到thrashing前，必需先大略對虛擬記憶體有點瞭解。虛擬記憶體的概念，其實就是將硬碟割出一塊空間，這一部份我們叫他虛擬記憶體（Virtural Memory），而原先的記憶體稱之為實體記憶體（Physical Memory）。　　


當程式要執行的部份，從虛擬記憶體（亦即硬碟）搬至實體記憶體再執行。由於硬碟的空間遠較實體記憶體為大，因此使用虛擬記憶體這種技術，可以讓程式不受實體記憶體容量的限制，此外由於行程（Process，指執行中的程式）只需將部份載入實體記憶體，因此可以讓更多行程同時存於實體記憶體，進而提高CPU的使用率。


　　Thrashing這種現象指的是，欲使用的資料從虛擬記憶體搬至實體記憶體時，實體記憶體可能有一部份需要被置換，這些置換的資料再搬至虛擬記憶體中。然而被置換的部可能馬上又要使用，再從虛擬記憶體搬至實體記憶體，如此週而復始不斷進行搬運的動作，所有時間都花在這些無關緊要的置換搬運，導致CPU的使用率大幅降低。　　
 
現在的電腦可以同時執行很多程式，如此CPU使用率大幅上升，達到最大的利用。然而執行的程式超過一定的數量時，很容易發生thrashing，CPU的使用率反而降低。


refer from:
http://blog.xuite.net/draz/draz/3826515

Win7: Login your computer directly

Open command application and key "netplwiz" to set the mode you want.

refer from:

http://briian.com/?p=5008

Win7: Open admin

cmd (use admin's authority by right click)

then "net user administrator /active:yes"

if you want to close it,change yes to no.

Freerunner: The problem of enter in Terminal emulator

1. You need to change keyboard type in your freerunner that is ruKeyboard.apk from
http://android-on-freerunner.googlecode.com/issues/attachment?aid=4852331778978639661&name=ruKeyboard_v1.3.4.apk&token=2bf2f673c0b38748aa74d0894a6006a0

2. Use adb to instll this .apk.

refer from:
http://code.google.com/p/android-on-freerunner/issues/detail?id=55

Android: Install ADB in Linux

1. Download http://www.4shared.com/file/182574434/c1225b3d/AndTools.html then execute it.


2. Install Android SDK from http://developer.android.com/sdk/index.html.

3. Update Android SDK that need to include ADB.

4. You need to add environment variable so input "$gedit ~/.bashre".

5. Key in "export PATH=$PATH:/home/light/sdk/platform-tools/" in the end of the opened file. (depends on your path of ADB)

6. Key in "$adb" to check this instruction existed.

refer from:
http://developer.android.com/index.html

Android: Install .apk by ADB

After your google phone has already communicated with computer successfully,input " $adb install xxx.apk"

Android: Use ADB in Linux

1. Connect your google phone with your computer by USB.

2. Input " $ifconfig " to see the new Ethernet card.(eg. eth1 or usb0).

3. Input " $ifconfig eht1 192.168.0.200 netmask 255.255.255.0".

4. Input " $ADBHOST=192.168.0.202 adb devices"
    then you'll see something like this:
        List of devices attached
        emulator-5554 device
    if you don't see it,Input "$adb kill-server"," $ADBHOST=192.168.0.202 adb devices"