windows 2008 backup script

WBADMIN start backup命令居然会覆盖制定的备份目标文件夹，这样每次只有最近的一次备份留了下来，这有什么意义呢？ 如果是在备份开始的前一刻系统发生故障，备份下来的也是失败的版本！ 为什么ms没有提供apple的time machine呢？？？
参考各种网站的建议，得到下面的脚本，他可以备份最近一周的脚本，分别放到week1到week7的目录里，适当修改一下可以备份任意期间的系统。
让task schedule每天自动执行backupsystem.bat就OK了。

主脚本：BackupSystem.bat

@echo off
::BackupSystem.bat
::demonstration script using WBADMIN.EXE on a
Windows Server 2008 Server

rem backup share UNC
set backupshare=\\mycompany-dc01\Backup

rem files and folders to include
set include=c:,d:

rem define date time variables for building the folder name
set m=%date:~5,2%
set d=%date:~8,2%
set y=%date:~0,4%
set h=%time:~0,2%
set min=%time:~3,2%
set sec=%time:~6,2%
FOR /F "tokens=*" %%A IN ('CSCRIPT c:\temp\WEEK.VBS //NoLogo') DO SET %%A

rem defining a new folder like \\mycompany-dc01\backup\RESEARCHDC\20091215_132532

set newfolder=%backupshare%\%computername%\Week%Week%

echo Creating %newfolder%

mkdir %newfolder%

rem run the backup
echo Backing up %include% to %newfolder%

wbadmin start backup -backuptarget:%newfolder% -include:%include% -vssFull -quiet

rem Clear variables
set backupshare=
set include=
set m=
set d=
set y=
set h=
set min=
set sec=
set newfolder=

星期取得脚本：WEEK.VBS

Wscript.Echo("Week=" & DatePart("w",Date,vbMonday,vbFirstJan1))