Day 1 计算机硬件组成 Computer hardware composition
一 PC与服务器 PC and servers
A desktop computer system typically runs a user-friendly operating system and desktop applications to facilitate desktop-oriented tasks. In contrast, a server manages all network resources. Servers are often dedicated (meaning it performs no other task besides server tasks)
个人计算机系统通常运行简便的操作系统和桌面应用程序。相反，服务器管理所有的网络资源。服务器通常是专用的(这意味着它不执行服务器任务之外的其他任务)
服务器的特点 Features of servers
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The ability to update hardware and software without a restart or reboot.
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Advanced networking performance.
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Automatic (invisible to the user) data transfer between devices.
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High security for resources, data and memory protection.
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不需要重新启动或重新启动就可以更新硬件和软件。
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先进的备份能力，频繁备份的关键数据。
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先进的网络性能。
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设备之间自动(对用户不可见)数据传输。
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资源、数据和内存保护的高安全性。
二 服务器分类 Server classification
按尺寸 By size
可分为1u , 2u, 4u
The classification by size can be divided into 1u , 2u, 4u
1u = 1.75 inches = 4.45 cm
按外形 By shape
可分为塔式服务器和机架式服务器和刀片服务器
it can be divided into tower server, rack server and blade server
The main difference between rack server & blade server is A Rack Server is an independent server installed in the case, while Blade Servers need to work with each other in one chassis.
机架服务器和刀片服务器的主要区别是机架服务器是安装在案例中的独立服务器，而刀片服务器需要在一个机箱中相互协作。
机架式服务器 Rack Server
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Rack server acts as the lone rider of all the needed components as a single powerful system. Rack servers could perform powerfully to run high-end applications.
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Rack servers are convenient to fit as it consumes less amount of physical space.
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Rack servers are usually equipped with internal fans, increasing airflows which makes it’s cooling more easier.
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Rack servers can be highly efficient when you require more than one server as they don’t require a huge chassis.
机架服务器作为一个强大的系统，作为所有需要的组件的独行侠。机架服务器可以强大地运行高端应用程序。
机架服务器非常方便，因为它消耗较少的物理空间。
机架服务器通常配备内部风扇，增加空气流量，使其更容易冷却。
机架服务器在需要多个服务器时可以非常高效，因为它们不需要巨大的机箱。
刀片服务器 Blade Server
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Blade servers can enable their massive chassis to supply power to multiple servers which reduces total power consumption for each blade server.
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Blade servers promote Hot-swappable features which could provide you redundancy when one blade faces a problem making it to be pulled and replaced much more easily.
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Blade servers require only one cable (often fiber) for running to the chassis which reduces the use of individual cables running for each blade server.
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Blade servers require minimal space and at the same time provide high processing power.
刀片服务器可以使其庞大的机箱为多个服务器提供电源，从而减少每个刀片服务器的总电源消耗。
刀片服务器提倡热插拔功能，当一个刀片服务器遇到问题时，可以提供冗余，使其更容易提取和替换。
刀片服务器只需要一条电缆(通常是光纤)就可以运行到机箱，这减少了为每个刀片服务器运行单独电缆的使用。
刀片服务器需要最少的空间，同时提供高处理能力。
塔式服务器 Tower Server
A tower server is a computer intended for use as a server and built in an upright cabinet that stands alone. The cabinet, called a tower, is similar in size and shape to the cabinet for a tower-style personal computer. This is in contrast to rack server s or blade server s, which are designed to be rack-mounted
在大小和形状上与塔式个人电脑机柜相似
三 服务器品牌 Server brand
DELL 戴尔
HP 惠普
四 去IOE 运动 Take off IOE
I=IBM (minicomputer)
O=Oracle (datebase)
E=EMC (memory device)
第一个是指IT架构的更新换代，具体说就是以IBM为代表的主机、以ORACLE为代表的关系型数据库，以及以EMC为代表的高端存储设备，被新型的云计算技术所替换，也就是我们常说的“云化”。
第二个是指针对外国IT设备，特别是美国产品的“严打”，减少甚至不再购买IBM、ORACLE、EMC等企业的产品。
第三，是建立与支撑系统云化配套的运行维护管理体系。
五 电脑和服务器的主要构成
主机 host machine
内存 Internal storage
中央处理器 CPU Central Processing Unit
主板 Main board
外设 device
存储 storage
磁盘 disk
光盘 optical disk
闪存 flash memory
输入设备 Input device
键盘 keyboard
鼠标 mouse
扫描仪 scanister
摄像头 webcam
输出设备 Output device
显示卡 display card
显示器 display
音箱 loudspeaker box
打印机 printer
服务器组成 Server composition
机箱 Case
电源 Power supply - the heart
不间断电源 UPS uninterruptible power system
中央处理器 CPU - the brain
风扇 fan
A fan on top of a computer processor. It helps pull and blow hot air off the processor, helping keep it cooler.
硬盘 Hard disk
机械硬盘 HDD hard disk drive
固态硬盘 SSD solid state drive
硬盘接口 hard disk interface
SAS
SATA
磁盘阵列 Raid Redundant Arrays of Independent disks
Raid 0
It's also known as "disk striping." With RAID 0, data is written across multiple disks. This means the work that the computer is doing is handled by multiple disks rather than just one, increasing performance because multiple drives are reading and writing data, improving disk I/O. A minimum of two disks is required.
在raid0中，数据是跨多个磁盘写入的。这意味着计算机所做的工作是由多个磁盘而不是一个磁盘来处理的，由于多个驱动器正在读取和写入数据，从而提高了性能，提高了磁盘I/O。至少需要两个磁盘。
Raid 1
A popular disk or solid state drive (SSD) subsystem that increases safety by writing the same data on two drives. Called "mirroring," RAID 1 does not increase performance. However, if one drive fails, the second drive is used, and the failed drive is manually replaced.
通过在两个驱动器上写入相同的数据来提高安全性。被称为“镜像”的 raid1 不会提高性能。但是，如果一个驱动器出现故障，则使用第二个驱动器，并手动替换出现故障的驱动器。
Raid 5
RAID 5 is a unique version of RAID that uses something called RAID parity. This technique uses parity information or bonus data to calculate any lost information. Parity is distributed among all drives in the RAID. RAID 5 requires roughly one free drive worth of space to store the parity
raid5是使用RAID奇偶校验的独特版本。这种技术使用奇偶校验信息或奖励数据来计算任何丢失的信息。奇偶校验分布在RAID中的所有驱动器中。RAID 5需要大约一个自由驱动器的空间来存储奇偶校验
Raid 10
RAID 10, also known as RAID 1+0, is a RAID configuration that combines disk mirroring and disk striping to protect data. It requires a minimum of four disks and stripes data across mirrored pairs. As long as one disk in each mirrored pair is functional, data can be retrieved
raid10，也称为raid1+0，是一种结合磁盘镜像和磁盘条带保护数据的RAID配置。它需要至少四个磁盘和横跨镜像对的条纹数据。只要每个镜像对中有一个磁盘是有效的，就可以检索数据
六 计算机体系三层结构与优化
The three-layer structure and optimization of computer system
应用程序 application program
操作系统 operating system
计算机硬件 computer hardware
运维的职责 duty of operation and maintenance
监控 monitor
备份 backups
优化 optimize
Day 1 exercise
1.你用过的服务器型号有哪些？配置如何？
What server models have you used?How is the configuration?
Dell r720 2u 双路，4个SAS硬盘 32G
1个CPU 4核 16G
2.程序、进程和守护进程的区别
The difference between programs, processes and daemon processes
1.程序是永存的;进程是暂时的,是程序在数据集上的一次执行,有创建有撤销,存在是暂时的;
2.程序是静态的观念,进程是动态的观念;
3.进程具有并发性,而程序没有;
4.进程是竞争计算机资源的基本单位,程序不是。
5.进程和程序不是一一对应的: 一个程序可对应多个进程即多个进程可执行同一程序; 一个进程可以执行一个或几个程序
3.提升用户体验的网站解决方案
Web solutions that enhance the user experience
4. buffer与cache区别
The difference between buffer and cache
A buffer is something that has yet to be "written" to disk. A cache is something that has been "read" from the disk and stored for later use. Reading from a disk is very slow compared to accessing (real) memory.
5.描述Raid 0 1的特点
Describe the characteristics of Raid 0 1
Raid 0- disk striping 条带化
速度快，无冗余，容量无损失
Fast speed, no redundancy, no loss of capacity
Raid 1 mirroring 镜像
100%冗余，容量损失半，最安全
100% redundancy, half capacity loss，the most secure
