IBM s/390 manual Frequently asked questions

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Chapter 6. Frequently asked questions

Q:Can I install a boot manager and have Linux (with FLEX-ES) and Windows on the same ThinkPad?

A:Yes, but you will need to do the installation yourself. You might consider completely

removing the primary hard disk and replacing it with a disk containing whatever version of Windows you prefer. However, the primary hard disk (as opposed to a second hard disk) is not intended for frequent removal.

Q:Does each S/390 user need a Linux userid?

A:No. A typical OS/390 TSO user, for example, never “sees” Linux.

Q:Must I use vi to administer the Linux system?

A:No. Linux has a number of other editors, some of which are very “PC-like.” However, you may find it easier to use vi to edit files whose names begin with a period.

Q:Why do I need to define emulated control units and channels? I did not need to do this with emulated I/O on P/390 and MP3000 systems. For these machines, I could simply define emulated devices.

A:There are two major reasons. The first is that working through (emulated) channels and devices provides a more accurate emulation of S/390 hardware. In most cases this has little practical effect. The second reason involves emulating multiple S/390 instances, and sharing emulated I/O--for example, shared DASD. This is a more complex situation that does not exist on a P/390 and is not permitted (via LPARs) on an MP3000. The emulated control units provide the logical interlock and queueing points for sharing devices according to S/390 architectural specifications.

Q: How real is the channel emulation? Can I make my system faster by defining lots of channels and spreading out my I/O devices?

A:As best we could tell, the emulated channels are not very real in this sense. Many system definitions we examined define only two or three channels of each channel type. We have noticed that it appears necessary to define separate channels for emulated 3174 or 3274 control units.

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