什么是三通阀?
An administrator needs to be able to restore a mksysb created on SERVER_A using a 4MM tape drive， to SERVER_B that only has an 8MM tape drive. There is an additional server that has a 4MM drive at /dev/rmt0 and an 8MM drive at /dev/rmt1. Which of the following procedures should be followed to convert from the 4MM to 8MM format（） ["tcopy \/dev\/rmt0.1 \/dev\/rmt1.1","dd if=\/dev\/rmt0.1 of=\/dev\/rmt1.1","tar -xvf \/dev\/rmt0.1tar -cvf \/dev\/rmt1.1","cpio -ivcBDUM < \/dev\/rmt0.1cpio -ovcBDUM. >\/dev\/rmt1.1"]
The system administrator wants to use a new jfslog /dev/fs1log with the filesystem /test/fs1 on the testvg volume group. The following commands were used to create the log and assign it to the filesystem： （1）mklv -t jfslog -y /dev/fs1log testvg 1 （2）chfs -a log=/dev/fs1log /test/fs1 While trying to mount the /test/fs1 filesystem the administrator received the error： "Cannot mount /dev/fs1lv on /test/fs1： A system call received a parameter that is not valid". What step did the administrator miss that most likely caused the error？（） ["Use the logform command to format \/dev\/fs1log as a jfslog","Use the chlv command to change the lv type of \/dev\/fs1log to jfslog","Use the chvg command to change the default jfslog of testvg to \/dev\/fs1log","Edit the \/etc\/filesystems file to change the log associated with \/test\/fs1 to \/dev\/fs1log"]
Companycom has successfully established their p5 LPAR environment on a POWER5 p5 590 running AIX 5.2. They are now ready to move to Virtual IO. What would be required to do Virtual IO?（） ["Apply APAR IY62262 to the current AIX 5.2 Maintenance level 04. Virtual IO Server is not required. ","Purchase Advanced POWER Virtualization software, upgrade to AIX 5.3 maintenance level 1 and apply APAR IY60349. Virtual IO Server is not required. ","Verify that there are enough resources to add a Virtual IO Server, upgrade to AIX 5.3 with APAR IY60349, create a Virtual IO Server after applying APAR IY62262. ","Verify that there are enough resources to add a Virtual IO Server, create a Virtual IO Server and apply APAR IY62262, verify that the system is at AIX 5.2 with Maintenance level 04."]
由于抽取样本的随机性造成的误差是（）。 ["无回答误差","测量误差","抽样框误差","抽样误差"]
现浇大模板住宅工程，该工程共8层，采用框架结构，建筑面积5285m2。该工程项目周围为已建工程，因施工场地狭小，现场道路按3m考虑并兼做消防车道，距离拟建房屋4m。搅拌机棚、砂石料只能在在建工程与已建工程之间的间隙堆放。施工供电设施已按照供电设计和施工总平面图布置完毕，并且建立了临时用电安全技术方案，方案内容包括：用电组织设计的全部资料；用电工程检查验收表；接地电阻、绝缘电阻和漏电保护器漏电动作参数测定记录表；定期检（复）查表。施工现场临时用电配置，以“三级配电、末级漏保”配电保护方式。 该项目在施工过程，发生如下几项事件：
事件一：在主体结构施工至第四层时，发现部分混凝土试块强度不合格，因此，施工单位聘请了有法定资质的检测单位进行现场实体检测，检测结果实体强度能够达到设计要求。
事件二：在外用电梯上升过程中，受七层阳台伸出的一根防护栏杆影响，架子工班长让正在脚手架上进行支模的木工王某立即拆除，王某随即进行拆除作业，结果不慎将钢管坠落，击中下方正在清理模板的张某，张某因安全帽被击穿，头部严重受伤，经抢救无效死亡。
事件一混凝土试块强度不合格的质量问题是否需要处理？并说明理由。
