IBM s/390 manual 3.2.3 OS/390 device configuration, FLEX-ES formats

The AWSCKD format was developed for P/390s where the underlying operating system used to emulate CKD drives is OS/2. OS/2 is a 32-bit operating system and has the usual restriction that a single file cannot be larger than 2 GB. An AWSCKD-emulated 3390-3 requires more than 2 GB, and is split into two AWSCKD files, the first is 2 GB and the second is about .8 GB9. The two files are usually placed in a single ZIP file.

FLEX-ES formats

FLEX-ES can handle the CD-ROM format discussed above. FLEX-ES emulates CKD drives, but the internal format (in the Linux files used for emulation) is different than the AWSCKD format. FLEX-ES provides a utility (ckdconvaws) to convert AWSCKD format to the FLEX-ES format for emulated CKD drives.

3.2.3 OS/390 device configuration

For the OS/390 R10 AD system, the first four volumes (first four CD-ROMs) contain an IPLable system on 3390-3 volumes, and we installed only these volumes. We also created three 3390-1 volumes for work space.

The AD system is already customized in many ways, including IODF device definitions. It is not the purpose of this redbook to discuss general AD system design.10 The following sections mention specific S/390 device numbers (“addresses”) such as A80 for the IPL volume. These addresses are included in the AD system; that is, they are included in the IODF distributed with the system.

We decided our initial OS/390 system (using the AD CD-ROM) would use the devices listed here. This represents a basic but IPLable OS/390 AD CD-ROM system.

Address	Device	VOLSER	FLEX-ES Name	Comments
A80	3390-3	OS39RA	/s390/OS39RA	IPL volume; OS/390 libraries
A81	3390-3	OS3RAA	/s390/OS3RAA	More OS/390 basic libraries
A82	3390-3	OS39M1	/s390/OS39M1	Paging, parmlib, catalogs, etc
A87	3390-3	OS39HA	/s390/OS39HA	System HFS data sets
560	3480			FakeTape emulating 3480
700	3270		mstcon	NIP & OS/390 master console
701-702	3270		L701 - L702	Local non-SNA VTAM
				terminals
E20, E21	CTC		eth0	Used for LAN TCP/IP interface

The AD system can use a much larger set of addresses and devices than shown here.11 These represent a basic useful system. Some of the addresses are arbitrarily chosen from the larger set provided with this AD system. The AD volumes containing the DLIBs, DB2, CICS, and IMS are not included in this list; they are not necessary for basic operation and we decided to not install them for our initial ThinkPad/EFS work.

9The two files contain the characters _1 and _2 as the last two characters of each file name. P/390 utilities recognize that the second file is a continuation of the first. Unlike FLEX-ES, the P/390 does not emulate 3390-9 drives. If it did, it would use four 2 GB files plus a 1 GB file to equal the 9 GB contained on a 3390-9 drive.

10A fairly detailed description of recent OS/390 AD systems is given in S/390 Partners in Development: OS/390 (and z/OS) New User’s Cookbook, SG24-6204.

11This means that the IODF distributed with the AD system contains a large number of defined devices and addresses. We selected a subset of these already-defined devices and addresses.

Chapter 3. FLEX-ES and OS/390 installation 23