seke blog: 2018

2018年12月13日星期四

how to check windows version

查看windows版本兩種方法:

1. 指令ver

    Microsoft Windows [版本 10.0.17134.471]

2. 指令 slmgr.vbs -dlv

    軟體授權服務版本: 10.0.17134.471

    名稱: Windows(R), Professional edition
    描述: Windows(R) Operating System, VOLUME KMSCLIENT channel
    啟用識別碼: x-x-x-x-x
    應用程式識別碼: x-x-x-x-x
    延伸的PID: x-x-x-x-x-1028-17134.0000-1382018
    產品金鑰通路: Volume: GVLK
    安裝識別碼: x
    部分產品金鑰: x
    授權狀態: 已取得授權
    大量授權啟用到期: 255777分鐘(178天)
    剩餘的Windows重設授權狀態計數: 1001
    剩餘的SKU重設授權狀態計數: 1001
    信任時間: 2018/12/13 下午06:42:18
    已設定的啟用類型: All

    最近的啟用資訊:
    金鑰管理服務用戶端資訊
      用戶端電腦識別碼(CMID): x-x-x-x-x
      已登錄的KMS電腦名稱:  x.x.edu.tw:1688
      KMS電腦IP位址: x.x.x.x
      KMS電腦延伸的PID: x-x-x-x-x-1028-9600.0000-2932015
      啟用間隔: 120分鐘
      更新間隔: 10080分鐘
      啟用KMS主機快取

2018年11月28日星期三

four design examples for the add function as class or instance methods

一個運算的方法到底要定義為類別方法或物件方法，完全取決於設計者。
底下以簡單的整數加法運算為例，說明定義為類別方法或物件方法時，製作及使用上的差別。
一般是類別設計者先決定運算要如何使用，再決定如何製作。

四種設計關鍵在於:  類別方法或物件方法 vs 結果回傳或覆蓋第1數

(1) 類別方法，回傳結果

 public class WholeNumber
 {
    public int number;

    public WholeNumber(int n)
    {
      this.number = n;
    }

    public String toString()
    {
      return String.format("%d", number);
    }

    public static WholeNumber add(WholeNumber n1, WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = n1.number + n2.number;
      return n;
    }

    // n3:7 = n1:3 + n2:4
    public static void main(String args[])
    {
      WholeNumber n1 = new WholeNumber(3);
      WholeNumber n2 = new WholeNumber(4);
      WholeNumber n3 = WholeNumber.add(n1, n2);
      System.out.printf("n3:%s = n1:%s + n2:%s\n", n3, n1, n2);
    }
  } 


(2) 類別方法，結果覆蓋第1數

 public class WholeNumber
 {
    public int number;

    public WholeNumber(int n)
    {
      this.number = n;
    }

    public String toString()
    {
      return String.format("%d", number);
    }

    public static void add(WholeNumber n1, WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = n1.number + n2.number;
      n1.number = n.number;
    }

    // n1:7 = n1:3 + n2:4
    public static void main(String args[])
    {
      WholeNumber n1 = new WholeNumber(3);
      WholeNumber n2 = new WholeNumber(4);
      WholeNumber n1_copy = new WholeNumber(3);
      WholeNumber.add(n1, n2);
      System.out.printf("n1:%s = n1:%s + n2:%s\n", n1, n1_copy, n2);
    }
  } 


(3) 物件方法，回傳結果

 public class WholeNumber
 {
    public int number;

    public WholeNumber(int n)
    {
      this.number = n;
    }

    public String toString()
    {
      return String.format("%d", number);
    }

    public WholeNumber add(WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = this.number + n2.number;
      return n;
    }

    // n3:7 = n1:3 + n2:4
    public static void main(String args[])
    {
      WholeNumber n1 = new WholeNumber(3);
      WholeNumber n2 = new WholeNumber(4);
      WholeNumber n3 = n1.add(n2);
      System.out.printf("n3:%s = n1:%s + n2:%s\n", n3, n1, n2);
    }
 } 


(4) 物件方法，結果覆蓋第1數

 public class WholeNumber
 {
    public int number;

    public WholeNumber(int n)
    {
      this.number = n;
    }

    public String toString()
    {
      return String.format("%d", number);
    }

    public void add(WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = this.number + n2.number;
      this.number = n.number;
    }

    // n1:7 = n1:3 + n2:4
    public static void main(String args[])
    {
      WholeNumber n1 = new WholeNumber(3);
      WholeNumber n2 = new WholeNumber(4);
      WholeNumber n1_copy = new WholeNumber(3);
      n1.add(n2);
      System.out.printf("n1:%s = n1:%s + n2:%s\n", n1, n1_copy, n2);
    }
 }

以上四種寫法也可以合併成一支如下類別，方便比較四種用法的不同:

 class WholeNumber
 {
    public int number;

    public WholeNumber(int n)
    {
      this.number = n;
    }
    
    public WholeNumber(WholeNumber n)
    {
      this.number = n.number;
    }

    public String toString()
    {
      return String.format("%d", number);
    }

    public static WholeNumber classAddReturn(WholeNumber n1, WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = n1.number + n2.number;
      return n;
    }

    public static void classAddOverwrite(WholeNumber n1, WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = n1.number + n2.number;
      n1.number = n.number;
    }

    public WholeNumber instanceAddReturn(WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = this.number + n2.number;
      return n;
    }

    public void instanceAddOverwrite(WholeNumber n2)
    {
      WholeNumber n = new WholeNumber(0);
      n.number = this.number + n2.number;
      this.number = n.number;
    }
/*
n3:7 = n1:3 + n2:4
n1:7 = n1:3 + n2:4
n4:7 = n1:3 + n2:4
n1:7 = n1:3 + n2:4
*/
    public static void main(String args[])
    {
      WholeNumber n1,n2,n3,n4,n1_copy;
      
      n1 = new WholeNumber(3);
      n2 = new WholeNumber(4);
      
      n3 = WholeNumber.classAddReturn(n1, n2);
      System.out.printf("n3:%s = n1:%s + n2:%s\n", n3, n1, n2);
      
      n1_copy = new WholeNumber(n1);
      WholeNumber.classAddOverwrite(n1_copy, n2);
      System.out.printf("n1:%s = n1:%s + n2:%s\n", n1_copy, n1, n2);
      
      n4 = n1.instanceAddReturn(n2);
      System.out.printf("n4:%s = n1:%s + n2:%s\n", n4, n1, n2);

      n1_copy = new WholeNumber(n1);
      n1_copy.instanceAddOverwrite(n2);
      System.out.printf("n1:%s = n1:%s + n2:%s\n", n1_copy, n1, n2);
    }
 }

Virtual Machine Spec for Google Colab Environment

Google Colab提供最多12小時連線的Jupyter Notebook開發環境，其2018年底層的虛擬機實測規格如下:

CPU: Intel(R) Xeon(R) TwinCore @ 2.20GHz x 2

Memory: 13GB

Drive: 347GB

GPU: Tesla K80 with 4992 cores at 556MHz + 11GB Memory

OS: Ubuntu 18.04.1 LTS

Time Limit: 12 hours

規格實測的python指令如下:

# https://stackoverflow.com/questions/48750199/google-colaboratory-misleading-information-about-its-gpu-only-5-ram-available
# memory footprint support libraries/code
!ln -sf /opt/bin/nvidia-smi /usr/bin/nvidia-smi
!pip install gputil
!pip install psutil
!pip install humanize
import psutil
import humanize
import os
import GPUtil as GPU
GPUs = GPU.getGPUs()
# XXX: only one GPU on Colab and isn? guaranteed
gpu = GPUs[0]
def printm():
 process = psutil.Process(os.getpid())
 print("Gen RAM Free: " + humanize.naturalsize( psutil.virtual_memory().available ), " | Proc size: " + humanize.naturalsize( process.memory_info().rss))
 print("GPU RAM Free: {0:.0f}MB | Used: {1:.0f}MB | Util {2:3.0f}% | Total {3:.0f}MB".format(gpu.memoryFree, gpu.memoryUsed, gpu.memoryUtil*100, gpu.memoryTotal))
printm()

!df
!cat /etc/issue
!nvidia-smi
!nvidia-smi -L

!cat /proc/cpuinfo
!cat /proc/meminfo

2018年6月27日星期三

create bootable iso from windows installation files

如果擁有Windows作業系統安裝檔案，可以利用ImgBurn軟體，將微軟安裝目錄製作成.iso，方便虛擬機安裝作業系統之用。其關鍵步驟在選擇正確開機檔案，及載入磁區數目。重要參數如下:

  1.Source: Windows作業系統安裝檔案位置
  2.Destination: .iso檔案位罝
  3.Advanced/Bootable Disc
     Make Image Bootable
       Emulation Type: None (Custom)
       Boot Image: \boot\etfsboot.com
       Platform ID: 80x86
       Developer ID: Microsoft Corporation
       Load Segment: 07C0
       Sectors To Load: 8
  4.Build

  其中，載入磁區數目為8，推測是因為etfsboot.com檔案為4KB，佔512B磁區8個。

參考: Youtube: How to create a Bootable ISO Image *from* a Bootable USB Drive

2018年1月25日星期四

how to decode web content in gzip or deflate format using Java API?

有些網站回傳網頁會進行內容壓縮，壓縮方法常見有gzip或deflate，
可由回傳內容的ContentEncoding標頭決定如何處理回傳的壓縮內容。

以Java為例，解壓縮寫法如下:


      // 設定下載網址
      URL url = new URL("http://comment.bilibili.tv/29545595.xml");  
      HttpURLConnection conn = (HttpURLConnection) url.openConnection();  
      //conn.setRequestProperty("Accept-Encoding", "identity");

      // 連線取得網頁輸入流
      conn.connect();  
      System.out.printf("con.getContentEncoding()=%s\n",conn.getContentEncoding());
      InputStream in = conn.getInputStream();

      if(conn.getContentEncoding().equals("gzip"))
          in = new GZIPInputStream(conn.getInputStream());  

      if(conn.getContentEncoding().equals("deflate"))
          in = new InflaterInputStream(conn.getInputStream(), new Inflater(true));

      // 從網頁輸入流列印內容到螢幕
      BufferedReader bin = new BufferedReader(new InputStreamReader(in, "UTF-8"));  
      String s = null;  
      while((s=bin.readLine())!=null){  
         System.out.println(s);  
      }  
      bin.close();

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2018年12月13日 星期四

how to check windows version

2018年11月28日 星期三

four design examples for the add function as class or instance methods

Virtual Machine Spec for Google Colab Environment

2018年6月27日 星期三

create bootable iso from windows installation files

2018年1月25日 星期四

how to decode web content in gzip or deflate format using Java API?

2018年12月13日星期四

2018年11月28日星期三

2018年6月27日星期三

2018年1月25日星期四