February 17, 2019

The Ultimate Install Fest: Linux on the IBM System/390 - page 3

Recycling the Mainframe with Linux

  • July 31, 2000
  • By Scott Courtney

As for the pricing issue, IBM has responded by introducing two new products, one hardware and one software. Both of these will be announced officially on August 2.

The Integrated Facility for Linux, or "IFL," is a dedicated processor node that plugs into a System/390 mainframe and runs only Linux. The instruction set is fully binary-compatible with other S/390 processors, but the microcode won't let it run IBM's OS390 or VM software. This reduced generality doesn't affect Linux users, except to lower the price of the board by about 65%, from US$375,000 to US$125,000, approximately. Linux will still run on the normal S/390 processor, but the new IFL is much more cost-effective if Linux is the desired operating system.

The IFL processor works just like a standard S/390 CPU module, and can be allocated in Logical PARtitions (LPARs) to allow dynamic resource management. Like other S/390 CPUs, the IFL shares the memory and I/O channels of the machine. IBM's "G6" class machines accept up to twelve CPUs total, of which eleven can be IFLs. Up to fifteen LPARs can be allocated on a single machine. If you need more, you can combine G6s into a giant Sysplex whose size is practically unlimited (you will run out of money first!). The system administrator can carve up those LPARs to assign any supported number of virtual CPUs to each Linux instance on the machine.

Virtual Image Facility: A Cheaper VM
The second new product from IBM is called Virtual Image Facility, or VIF. Readers of my first S/390 article (http://linuxplanet.com/linuxplanet/reports/1532/1/) will recall that IBM's Virtual Machine (VM) hypervisor allows many hundreds--or even a few thousand--instances of Linux to run on a single physical CPU or LPAR. This is great for sites that already have a VM license for other applications, but VM is expensive, and Linux customers had trouble cost-justifying the VM purchase.

In response, IBM will announce the Virtual Image Facility as a low-end alternative to VM. VM is more than just a hypervisor to allocate virtualized resources; it is a full-blown operating system that runs large-scale applications. With VIF, IBM has stripped off the general-use parts of VM, leaving only the hypervisor core and some simple management tools, and reducing the price accordingly. VIF isn't nearly as versatile as VM: you can't run OS390 inside VIF, for example, nor can VIF run inside VIF. On the other hand, VIF is a one-time license priced at around US$20,000, a fraction of the ongoing software lease price for VM itself.

VIF is not only cheaper than a full VM license, but also easier to install, according to Pete McCaffrey. He also asserts that the one-time-fee pricing model--uncommon for mainframe software--is a direct response to demand from customers. McCaffrey adds that much of the IBM middleware for Linux will also use the one-time model when it is released over the next several months. Middleware products, in IBM parlance, include DB2 Universal Database, MQ Series messaging, and Tivoli system administration and backup tools, among others.

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