[Description] reposted from vistafans.com
Article The introduction is very detailed, and I also talk about some personal experience.
For developers, business is sufficient, and 2G is the best configuration. After 1G is installed with the application software, it will be much slower, 512? Feel it for yourself.
Video Card, with independent is the best, but it is better to more than 128, the best is 250 video memory.
Hard drive, for friends in the garden, 30 GB, believe me, that's right.
In addi
-------------------- Windows Phone 7 Mobile Phone development,. Net training, and hope to communicate with you! ----------------------
The book says that group by can divide a table into logical groups and calculate aggregate statistics for each group .. I didn't understand the meaning of this sentence at first, and I finally understood it with the help of everyone.
The literal meaning of group by is: grouping.
Assume that there is a t_person table.The table has the following attributes: ID, na
My virtual machine version is 4.3.20, Windows version is Windows 8, but today suddenly found that VirtualBox can not boot, reported errors as follows:In order for the search engine to retrieve this error message, I pasted the text of the error message below:
NtCreateFile (\device\vboxdrvstub) Failed:unkown Status-5600 (0XFFFFEA20) (RCNT=0XE986EA20)Vboxdrvstub error:ntdll.dll:7982 differences between 0x300c and 0x4fff in #1 (. text), first:4c!
special Mac as the source MAC address. However, the latest version of the S3600/5600 series switches is supported by using the PORT-MAC command in System view.for fixed source MAC addresses, the H3C switch is the source Mac that does not learn BPDU messages, but some of the friend devices are learning from the source Mac of BPDUs, so the MAC address drift Alarm is sometimes recorded on the friend device. Blogger recommends: for V3 platform switches s
Copy the original server's configuration file back to the new server Authz, passwd, svnserver.conf2. Incremental backup#svnadmin dump/svn/svn/app-r 5200:5600--incremental >/svn/svndump/app_56005200 is the latest version at the time of the last full-volume backup, and 5600 is the current latest version.Import: Svnadmin Load/svn/svn/app Svnadmin Hotcopy Method:1. BackupSvnadmin hotcopy/svn/svn/app//data/svn.
The basic usage of grouping functions is described earlier, and several more advanced uses of group by are described below.
1, rollup in Oracle database with the GROUP BY command, you can provide summary of information functions (similar to subtotals)
Sql> SELECT Deptno, Job,sum (SAL) from EMP1 Group by Deptno,job
2 order by Deptno,job;
DEPTNO JOB SUM (SAL)
---------- --------------------------- ----------
Ten Clerk 1300
Ten MANAGER 2450
Ten PRESIDENT 5000
6000 ANALYST
1900 Clerk
MANA
the database with the following data:
Id
NAME
SALARY
100
Jacky
5600
101
Rose
3000
102
John
4500
Requirements:
1. Create the table and enter the appropriate data.
2. Information about its name and salary can be queried based on a specific ID.
3. The employee information is based on a query that is larger than a specific salary.
According to the previous requ
|-----------------------------------------------------------------------------Can be found that this method is not only SQL writing convenience, performance can also be improved.At this time, suppose another person came running to say: In addition to the above data, he also needs the overall performance of each position, you just have to change the rollup to a cube can be, for example, see below:--Cube Group Select a.dname,b.job, SUM (b.sal) sum_salfrom dept a,emp b WHERE a.deptno = B.deptnogr
the database EMP table with the following data:
Id
NAME
SALARY
100
Jacky
5600
101
Rose
3000
102
John
4500
Requirements:1. Create the table and enter the appropriate data.2. Information about their name and salary can be queried based on a specific ID.3. The employee information is based on a query that is larger than the specific salary.Dep
|-----------------------------------------------------------------------------Can be found that this method is not only SQL writing convenience, performance can also be improved.At this time, suppose another person came running to say: In addition to the above data, he also needs the overall performance of each position, you just have to change the rollup to a cube can be, for example, see below:--Cube Group Select a.dname,b.job, SUM (b.sal) sum_salfrom dept a,emp b WHERE a.deptno = B.deptnogr
, Centrino, AMD PowerNow, Transmetta, Intel SpeedStep, Athlon-64, Athlon-X2, Intel Core 2Open it. If not, it will be useless to open it.CupsdCUPS printer support. If there is no printer or another type of printer, you can turn it off.DhcdbdD-BUS system network interface, mainly to provide you with network connection settings, it is strongly recommended to open, unless you use a fixed IP to access the Internet.FirstbootThe User Wizard after the install
Networking.Bluetooth, hcid, hidd, sdpd, dund, pandBluetooth-related. if there is no Bluetooth, turn it off.Btseed, bttrackBT-related. if you cannot use BT, you can disable it.CapiISDN hardware support, most users can turn offCpuspeedCPU speed adjustment if you are using Pentium-M, Centrino, AMD PowerNow, Transmetta, Intel SpeedStep, Athlon-64, Athlon-X2, Intel Core 2Open it. if not, it will be useless to open it.CupsdCUPS printer support. if there is
Source: e Silicon Valley powerNow broadband networks are widely used. In actual use of broadband, the network bandwidth required for browsing web pages, chats, and other applications is not high. For home or small office sites with multiple computers, if you can allow multiple computers to share one broadband account to access the Internet, you can make full use of the network bandwidth, so that more people can enjoy the internet. In addition to share
Most servers are configured as 24-hour running devices. Therefore, server energy-saving technologies are more important than personal products such as PCs and laptops. Generally, there are two kinds of energy-saving technologies on servers. One is energy-saving technologies for processors, such as the Power Islands technology used by IBM on Power5, Intel's SpeedStep and AMD's PowerNow! The other is power supply optimization and management, such as Int
many laptopsNow more and more desktops support this feature. If your CPU is: pew.m, Centrino, amd powernow,Transmetta, Intel speedstep, Athlon-64, Athlon-X2, Intel Core 2You should enable it. If you want your CPU to run at a fixed frequency, disable it.
Linux services ):CronSeeAnacron.
Linux services ):Cupsd, cups-config-daemonPrinter problems. If you have a cups-compatible printer driven in fedora, you should enable it.
Linux services ):Dc_clie
for enhanced speedstep TechnologyCPU driver, while amd needs to provide support for powernow! Technical CPU driver.
In the upper layer of the cpufreq module, governor is used as the decision maker to select the appropriate target operating frequency. according to certain standards, the CPU is selected at the appropriate time.Suitable for running frequency, and use the interface defined by the cpufreq module to operate the underlying CPU-related Varia
, AMD-3DNow !; (2) Virtual Micro Instruction Set: Intel-VT, AMD-SVM; (3) power-saving micro Instruction Set: Intel-SpeedStep, AMD-PowerNow !; (4) 64/32-bit compatible technology: Intel-EM64T; CPU-Z this software can see the current CPU support instruction set, take me as an example: Can see MMX, SSE: Improve the Performance of multimedia processing; EM64T (Extended Memory 64 Technology): Intel's 64-bit instruction set, compatible with 64-bit, indicate
this feature. If your CPU is: pew.m, Centrino, amd powernow, transmetta, Intel speedstep, Athlon-64, Athlon-X2, one of Intel Core 2, you should turn it on. If you want your CPU to run at a fixed frequency, disable it.
Linux services ):CronSeeAnacron.
Linux services ):Cupsd, cups-config-daemonPrinter problems. If you have a cups-compatible printer driven in fedora, you should enable it.
Linux services ):Dc_client, dc_serverThe disk cache (distcache) i
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