IBM s/390 manual Terminology

￿It should probably have the integrated Ethernet adapter, and possibly a second (PCMCIA) Ethernet adapter or a PCMCIA token ring adapter (depending on your requirements).

ThinkPad models change frequently and the above requirements may need to be adjusted to match current offerings. The author used a T20 ThinkPad (which met the other requirements) and had no problem with it. However, from a formal support viewpoint, only selected ThinkPad models should be used. At the time of writing, these were the A21p and A22p machines.

No particular disk drive size is required. A system needs about 1.5 GB for Linux. Most of the remaining disk space can be used for emulated S/390 drives. An emulated drive takes approximately the same number of bytes on the ThinkPad disk as are available on a “real” drive. A 3390-3, for example, requires about 2.8 GB on the ThinkPad disk. It is convenient to have extra space—say 2 GB—left for a work area.

Using two disk drives allows some overlap of drive operations. We did not attempt to measure this and we suspect that the effect is small. FLEX-ES provides very effective cache functions for emulated drives and this greatly reduces the actual disk drive I/O rates (especially seek rates) compared to “real drives” on “real S/390s.”

1.4 Terminology

EFS descriptions can become confusing if the terminology is not well defined. These are important terms:

￿Processor means a PC processor in the ThinkPad (or a Server processor in larger platforms).

￿Server means our underlying ThinkPad hardware.

￿Server operating system means Linux for the ThinkPad/EFS system described in this redbook.

￿S/390 CPU (or simply CPU) means an emulated single S/390 CPU engine.

￿S/390 system means an emulated S/390 (in the EFS system) that might have more than one emulated S/390 CPU engine.

￿Instance (or FLEX-ES instance) means an emulated S/390 system. We can run several FLEX-ES instances if we have sufficient resources.

￿OS/390 means the S/390 operating system. We could also use VM/ESA or VSE/ESA, but we elected to work only with OS/390 and z/OS (31-bit mode).

￿ThinkPad/EFS is a generic name. The business partners providing this product often have their own names for their specific implementation of the product.

For any FLEX-ES instance, there is a one-to-one correspondence between processors enabled for S/390 and S/390 CPUs. Running multiple instances is something like running multiple OS/390s in separate LPARs (but is not quite the same). We can run multiple instances of single-CPU S/390s in a ThinkPad/EFS system.

6S/390 PID: ThinkPad Enabled for S/390