z/Linux Updates

Linux on IBM Z originated as two separate efforts to port Linux to IBM's largest servers. The first effort, the "Bigfoot" project, developed by Linas Vepstas in late 1998 through early 1999, was an independent distribution and has since been abandoned.[1] IBM published a collection of patches and additions to the Linux 2.2.13 kernel on December 18, 1999, to start today's mainline Linux on Z.[2] Formal product announcements quickly followed in 2000, including the Integrated Facility for Linux (IFL) engines. Think Blue Linux was an early mainframe distribution consisting mainly of Red Hat packages added to the IBM kernel.[3] Commercial Linux distributors introduced mainframe editions very quickly after the initial kernel work.

At the start of IBM's involvement, Linux patches for IBM Z included some object code only (OCO) modules, without source code.[4] Soon after IBM replaced the OCO modules with open source modules. Linux on z is free software under the GNU General Public License.

According to IBM, by May, 2006, over 1,700 customers were running Linux on their mainframes.[

Linux on z gives the flexibility of running Linux with the advantages of
fault-tolerant mainframe hardware capable of over 90,000 I/O operations per second[8] and with a mean time between failure (MTBF) measured in decades.Using virtualization, numerous smaller servers can be combined onto one mainframe, gaining some benefits of centralization and cost reduction, while still allowing specialized servers. Instead of paravirtualization, IBM mainframes use full virtualization, which permits workload density far greater than paravirtualization does[ Combining full virtualization of the hardware plus lightweight Virtual Machine containers that run Linux in isolation (somewhat similar in concept to Docker) result in a platform that supports more virtual servers than any other in a single footprint,[which also can lower operating costs. Additional savings can be seen from reduced need for floor space, power, cooling, networking hardware, and the other infrastructure needed to support a data center. IBM mainframes allow transparent use of redundant processor execution steps and integrity checking, which is important for critical applications in certain industries such as banking.[citation needed]. Mainframes typically allow hot-swapping of hardware, such as processors and memory. IBM Z provides fault tolerance for all key components, including processors, memory, I/O Interconnect, power supply, channel paths, network cards, and others. Through internal monitoring, possible problems are detected and problem components are designed to be switched over without even failing a single transaction In the rare event of failure, firmware will automatically enable a spare component, disable the failing component, and notify IBM to dispatch a service representative. This is transparent to the operating system, allowing routine repairs to be performed without shutting down the system. Many industries continue to rely on mainframes where they are considered to be the best option in terms of reliability, security, or cost.