[MUSIC] On this page we get a view of an LDF, and LDF is a VCEM leader data set used by HCD, the hard work configuration definition program. It is used to create something called LDF's. And LDF is simply an input output definition file, which contains information about the our configuration, such as the outbreak system, the switch data if you're using it, the channel data, the control need data, and the device data. It also includes the EDT definitions. It is also used to make dynamic changes, which means without taking down your system you can add or delete devices from your system while it's up and running. On the next visual we see the SYS1.PARMLIB. It is a required data set that contains all the control parameters for the whole system. It has many, many customizable parameters, too many to even list them in this course or even to explain. The PARMLIB is an important data set in the zeros out bring system and can be thought of as performing a function similar to the slash ETC on a unique system. This parameter contains the options and parameters that tell the data centers configuration and resources. As the data center needs changes, these parameters can also change. You should always closely monitor the PARMLIB because they play a major part in the control and the performance and security of your system. Zero West logical PARMLIB provides a central location for the specification of the systems options and the parameters. During the system initialization or the IPL, the system reads the parameter information and SYS1.PARMLIB and have reached the logical PARMLIB datasets. It combines information along with the system operated commands entered during the appeal process. SYS1.PARMLIB library and other logical PARMLIB datasets can reside and advisable to have him on the series volume. As seen in this visual, if you set up correctly, you can use one LDF to IP multiple systems and the SYS plex. SYS plex will be discussed later but has shown this picture in the SYS plex, all the systems will seem like one single system few to you as a user. On the next visual we see the LOADxx member. This is also a very important part of the appeal process. This picture shows how if you set your PARMLIB members up correctly, one LOADxx member can be used to IPO and successfully bring up several L pars or system images. So, in the SYS plex you could bring up 32 systems at once, with just one LOADxx member. So, what is the LOADxx member? As mentioned, is one of the most important members of the SYS1.PARMLIB family. The LOADxx member is required if you want to IPL zero was image. You can have many LOADxx members on your system, but the xx is the suffix of the only LOADxx member that you use at the IPO time. It contains alga configuration. It contains the LDF physical Daz D, where the configuration information exists. It will have pointers to the nucleus based on the subjects of ID specified on the nuclear statement are on the load farm. It contains the master catalog specified in this Scott's statement. And finally, it specifies the ISS member which we used based almost the SYSPARM statement. What is this SYSRES? This daisy volume will be initialized by your system programmer to be used as SYSRES IPL. The load address will contain the address, it will contain two very important things to make your eye feel successful. One is, what SYS1.NUCLEUS this IPL is to use, and second, what IPLTEXT this IPO use. As mentioned earlier, it will also contain the SYS1.SVCLIB, which has recovery teams for your IPL. Your system program will format this daisy volume with utility. So it has a bootstrap on cylinder zero, head zero, record one, an IPLTEXT at record four. I'll discuss next how these fit in the IPL process. So for now there's a wrap and we come back the next unit will discuss the IPO process. [MUSIC]
