Linux Introduction. Simon COTER Director of Product Management Oracle VM & VirtualBox

Transcription

1 Linux Introduction Simon COTER Director of Product Management Oracle VM & VirtualBox December 19 th, 2018

2 Safe Harbor Statement The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle s products remains at the sole discretion of Oracle. 2

3 Before Linux In 80 s, Microsoft s DOS was the dominated OS for PC Apple MAC was better, but expensive UNIX was much better, but much, much more expensive. Only for minicomputer for commercial applications People was looking for a UNIX based system, which is cheaper and can run on PC Both DOS, MAC and UNIX were proprietary, i.e., the source code of their kernel is protected No modification is possible without paying

4 GNU project Established in 1984 by Richard Stallman, who believes that software should be free from restrictions against copying or modification in order to make better and efficient computer programs GNU is a recursive acronym for GNU's Not Unix Aim at developing a complete Unix-like operating system which is free for copying and modification Companies make their money by maintaining and distributing the software, e.g. optimally packaging the software with different tools (Redhat, Slackware, Mandrake, SuSE, etc) Stallman built the first free GNU C Compiler in But still, an OS was yet to be developed

5 Beginning of Linux A famous professor Andrew Tanenbaum developed Minix, a simplified version of UNIX that runs on PC Minix is for class teaching only. No intention for commercial use In Sept 1991, Linus Torvalds, a second year student of Computer Science at the University of Helsinki, developed the preliminary kernel of Linux, known as Linux version 0.0.1

6 Message from Professor Andrew Tanenbaum " I still maintain the point that designing a monolithic kernel in 1991 is a fundamental error. Be thankful you are not my student. You would not get a high grade for such a design :-) (Andrew Tanenbaum to Linus Torvalds) Soon more than a hundred people joined the Linux camp. Then thousands. Then hundreds of thousands It was licensed under GNU General Public License, thus ensuring that the source codes will be free for all to copy, study and to change.

7 What is Linux? Operating System means the sum of kernel and user-space tools, like: Libraries (glibc,...) shells (sh, ksh, bash, csh, tcsh, zsh,...) core utilities (ls, cat, find, tar, df,...) compilers (gcc, icc) Linux Kernel manages the hardware interface (CPU, MMU, I/O) for user process Linux is the only Kernel (UNIX based) even if usually we recognize the entire Operating System

8 Kernel Linux: the birth Linux was born in 1991 as a personal university project from Linux (Benedict) Torvalds because he thinks that Minix (16-bit microkernel) is not adequate for i386 systems. 1991, August: annuncio su comp.os.minix I've currently ported bash(1.08) and gcc(1.40), and things seem to work. This implies that I'll get something practical within a few months [...] Yes - it's free of any minix code, and it has a multi-threaded fs. It is NOT portable (uses 386 task switching etc), and it probably never will support anything other than AT-harddisks, as that's all I have :-(. 1991, September: release 0.01 source code available but product is not commercially redistributable

9 GPLv2: a new OS is finally available 1992 February: Linux Kernel 0.12 released under GPLv2 1984: Richard Stallman (MIT) created GNU project with the target to build an open-source development environment where, thanks to GPL licensing, code must be distributed within the community Tools e libraries have grown (gcc, bash, glibc, coreutils)...but GNU- Project Kernel (Hurd) is not ready Linux Kernel and Tools/Libraries available into GNU together are able to build a new Operating System totally open-source

10 Development Model Philosophy: release early, release often Starting from Release (March 1994) the new model has adopted (dual tree) 2 nd even release digit => stable versions (1.0.x, 1.2.x,...) 2 nd odd release digit => development versions (1.1.x, 1.3.x,...) When stable release is good enough the development branch will be opened When development is feature-rich enough, freeze period begins

11 Kernel 1.2, 2.0 and RedHat March, 1995: Kernel 1.2 introduced binary support for SPARC, Alpha, MIPS RedHat starts in 1995 with firsts desktop versions that helps managing by GUI March, 1996: RedHat 3.0.3, Kernel 2.0 ready June, 1996: Kernel 2.0 released (SMP support, dynamically autoloadable modules, new CPU compatible)

12 Stability, feasibility..and further Vendors Kernel 1.2 is so stable that it had been used on HTTP-Server machines (with Apache) on Internet, with high uptimes Kernel 2.0, with its extended module architecture. This model is also used today and it s the principle that allowed to build one-size-fitsall Kernel IBM, HP and Intel recognize Linux like a solution to sell their HW and start to have dedicated internal resources on the project RedHat begins to release Kernels with patches non available on the mainline but continues to work to keep mainline code alligned and updated (this model is still alive)

13 Linux decision-making System Core of choices is the mailing-list linux-kernel; there are further mailing list related to other components like netdev, linux-scsi, linuxide, linux-usb,... On these ML you can provide your ideas, but it s strongly suggested to add a draft working code ( show me the code ); all theoretical concepts could be ignored.

14 What if Torvalds is hit by a bus? With Torvalds there is a restricted group of trusted developers David Miller (networking, SPARC port) Alan Cox (di tutto, rel. mgr. 2.2) Andrew Morton (-mm tree, rel. mgr. 2.6) Jeff Garzik (network drivers, ATA) Ingo Molnar (scheduler, x86-git) Christoph Hellwig, Al Viro (reviewers) There are also further maintainers of specific parts Torvalds today is the final judge in case of conflicts ( benevolent dictator )

15 Kernel bug reporting and are the official bug-reporting methods Each Linux distribution has its own support forum and/or bug tracking system Bug reported to Oracle Linux are managed by Oracle bug-tracking system and, eventually, forwarded to the mainline Kernel maintainers (like all official distributions)

16 Kernel 2.2 Released in January, 1999 Improved scalability (SMP) Further instructions support for AMD and Intel CPUs Further drivers (mostly new SCSI) Improved APM (Power Management Support) NTFS support (read-only) Foundation for Enterprise-Level Features

17 Kernel 2.4 & (stable) Released in January, 2001 Further improvements (threads, network cards, disk controllers...) LVM and USB now possible New Networking Layer Scalability (SMP) until 16CPUs IA64 and S/390 now supported Pre-releases (-pre) available for 2.4 Release candidates (-rc) available for 2.4 (stable) and 2.5 (unstable)

18 Kernel 2.6 Released in December, 2003 NUMA Support, HyperThreading USB 2.0, SATA, direct I/O on block devices 16 TB fs, autoscaling open files limit, 4096 minor device ids... Preemptible kernel, SELinux Introduzione iniziale di sysfs (/sys) Nuovo modello di sviluppo: niente 2.7, ne' 3.0!...o no?

19 Kernel Development & Lines of code

20 Enterprise and Community Distributions Different targets with different expectations RHEL, SuSE and OL: one major release when stable Fedora: one major release every 6 months but... unstable kernels continue to supply features and enhancements to stable ones

21 Why Oracle Linux? Linux stability and feasibility involve low risks to an infrastructure support RedHat Enterprise Linux as landmark (with double kernel available) Fast ad-hoc fixed for Oracle Products on top Single-vendor support First release for ARM64 now available for free

22 Q & A Copyright 2015, Oracle and/or its affiliates. All rights reserved. 22

23 Stay Connected Blogs.oracle.com/linux Blogs.oracle.com/virtualization Oracle Linux Experts Group Oracle VM Group YouTube.com/OracleLinuxChannel YouTube.com/OracleVirtualization Visit us at:

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