IBM s/390 manual Q What is the difference between swapping and paging?

Q:If I obtain faster ThinkPads, can I ask FSI to alter my license? Do I need to notify IBM?

A:Yes, you can ask FSI for a new license key. (You must do this because your old key will not work with the faster processors.) You do not need to purchase a new license, assuming you have retained the same dongle. FSI does not notify IBM or any other software vendor. You need to manage any potential S/390 software fee changes related to the increased MIPS of your new machine. This is obviously a complex area, and these processes may change in the future.

Q:What is the difference between swapping and paging?

A:None, in these discussions.

Q:You mention MIPS in the 10-12 range; business partners talk about 16-20. Which is correct?

A:Both and neither. An emulated S/390 has a much wider range of MIPS than a “real” hardware S/390. Any MIPS measurement is very strongly dependent on the instruction mix and the addressing mix involved, as well as the emulation techniques used. We could probably contrive code to produce anything from below one MIPS to 30+ MIPS. We try to use conservative numbers in this series of redbooks, while marketing representatives tend to use optimistic numbers. An exact MIPS number simply does not exist.

Q:How is floating point performance?

A:It is acceptable for casual use, but you would probably not select this platform for major floating point applications. Binary (IEEE) floating point has considerably better performance than hex floating point.

Q:There are always new Linux functions available, as well as kernel fixes and upgrades. Should we install these? Do we need to reinstall any part of FLEX-ES afterward?

A:If you have a stable system, we suggest you do not apply Linux changes. You should regard your EFS system as a S/390 and not as a Linux machine. If you do rebuild the Linux kernel, you will need to reinstall the FLEX-ES msgmgr package.

Q:How can I tell whether my Ethernet connection is running at 10 or 100 Mbps?

A:We did not find a convenient way to do this at the ThinkPad end. Many Ethernet hubs have an LED that indicates 100 Mbps operation and you might look for this.

Q:Can I use DHCP to obtain a LAN IP address?

A:Yes, you could do this for Linux TCP/IP, but not for OS/390 TCP/IP. However, this is probably not a practical solution. Your EFS system is essentially a S/390 server, not a client, and you will probably need a stable IP address for it.

Q:How difficult is it to change the IP address of my system?

A:You are likely to have two IP addresses: one for Linux and one for OS/390. To change the OS/390 address you must edit the PROFILE data set and then restart TCPIP. If you are sharing a ThinkPad Ethernet adapter with Linux, you will also need to change the IP address in the FLEX-ES resource stanza that defines the emulated 3172. To change the Linux IP address:

(gnome): Programs --> System --> Network Configuration. Select the Interfaces tab. Deactivate the appropriate interface. Edit the interface to change the IP address. Activate the interface. Save. Quit.

Chapter 6. Frequently asked questions 67