Linux Learning Basics _unix Linux

1, what is Linux?

To be exact, the Linux kernel (the core program of the system), whose kernel copyright belongs to Linus Torvalds, is issued under the GPL (GNU general public License) Copyright Agreement, and anyone can copy (copy) and modify ( Change), package distribution (distribute), sales, but can not add any restrictions at the time of distribution, and all the original code must be public, so anyone can get all the execution files and the original code.

For Linux users and system administrators, Linux refers to a complete operating system that contains Linux kernel, utilities (System Tools), and application (application software). Linux applications are developed by the Free Software Foundation (FSF), and many enthusiastic programmers around the world have developed or ported many applications for Linux, including X-windows, Emacs, TCP/IP networks (including SLIP/PPP/ISDN), etc. Now Linux (including the kernel and a large number of applications) is already up to 200M to execute the program and will be larger (about 500M) after the full installation.

Linux is essentially a Unix "clone" or UNIX-style operating system that is compatible with most UNIX standards (such as IEEE Posix,system V,BSD) at the original code level, and it complies with the POSIX specification, for example, for System V, It can be run after the program source code has been recompiled under Linux, and for BSD Unix, its executable files can be run directly in the Linux environment.

Linux logo is cute penguin, as for why the use of penguins, Linus is said: The other is used by others, penguins, not also very cute?! The Linux author publishes just one kernel, and some companies or organizations distribute the kernel, the original code, and related applications together, resulting in a different Linux release (distributor) version, with a more famous release redhat, SlackWare , S.U.S.E, Debian and so on.

2, the development of Linux history?

The history of Linux dates back to 1990, Linus Torvalds, a student at the University of Helsinki in Finland, originally wrote a program in assembly language to handle multitasking in 80386 protection mode, later from Minix (for operating system teaching, very small Unix) Was inspired to write a better minix than Minix, and began to write some hardware device drivers, a small file system ..., This 0.0.1 version of Linux came out, but it must be in the Minix machine to play after compiling, this time the Linus has been completely "out of possession", decided to kick open Minix "revolution", so on October 5, 1991 released a Linux 0.0, 2 version, This version is already ready to run bash (a software that communicates with the OS kernel) and GCC (the GNU C compiler).

Linus from the outset, decided to freely spread Linux, including the source code, he put the source code online, and immediately attracted the attention of enthusiasts, they have joined the Linux core development work through the Internet, a large number of high-level programmers to join, so that the rapid development of Linux, by the end of 1993 , Linux 1.0 was finally born. Linux 1.0 is already a full-featured operating system, its core is compact and efficient, can give full play to the performance of the hardware, the 4 m memory of the 80386 machine also performed very well.

A lot of people have a misunderstanding of Linux, that is, always put Linux and low-end hardware platform to connect together, In fact, starting with the 2.1.XX-series kernel, Linux began to move up the path, after about 1.3, began porting to other hardware platforms, including the so-called fastest CPU---Digital Alpha (currently the highest frequency), At present Linux can give full play to the performance of hardware, can include low-end to high-end of all applications.

Linux joins the GNU and follows the public Copyright license (GPL), because does not exclude the merchant to the free software further development, does not reject the development commercial software on the Linux, therefore causes the Linux to start again the leap, has appeared many Linux distributions, like Slackware, Redhat , Suse, Turbolinux, OpenLinux and more than 10 kinds, and are also increasing, and some companies on Linux to develop commercial software or other UNIX platform software porting to Linux, many of the IT industry today, such as IBM, Intel, Oracle, Infomix, Sysbase, Corel, Netscape, CA, Novell and so on all announced support linux! Merchants to join to make up for the lack of pure free software and development barriers, Linux can be quickly popularized.

3. Why use Linux?

Using Linux allows you to achieve the performance of high-end systems on a relatively low-cost Intel X86 hardware platform, and many users use benchmarks to test on X86 machines running Linux and find that they can match the performance of the midsize workstations of sun and digital companies. In fact, not only many enthusiasts and programmers in the use of Linux, many business users such as Internet service Providers (ISPs) also use Linux as a server to replace expensive workstations, these server system stability is the highest record of 600 consecutive days did not encounter a system crash!

★ If you can not stand the frequent crashes of windows, want to change the system platform, choose Linux, you will be surprised to find Linux is fairly stable, performance is also very good.

★ If you want to learn about operating systems, such as UNIX, you can start with Linux, because people who are crazy about Linux are quick to learn about UNIX, Linux is open source OS, follow the public Copyright license (GPL), but also promising, completely free, You don't have to spend time and again buying a software license.

★ If you are it enterprise, Linux is so hot, potential business opportunities immeasurable, study it as early as possible in order to seize the commanding heights for future development.

★linux is ideal for developing internet/intranet, using its open source code, you can develop Web servers, routers, embedded systems, network computers, personal digital assistants, Oracle,infomix,sysbase, IBM supports Linux, and it's good to use it as a database platform, and using Linux can greatly reduce the total cost of development.

★ Open the original code of Linux allows you to have full control of the system, the original code open, you can according to their own needs to add or remove certain functions, at will create their own operating system, the development of independent copyright operating system, Linux is a way.

4, what can Linux do?

Linux now surpasses commercial UNIX systems in many ways, and it supports multi-user, multiple processes, multithreading, real-time, powerful, and stable, and can run on Intel processors, Dec Alphas, Motorola's m68k processors, Sun Sparc, PowerPC, MIPS and other platforms, can run the hardware platform is currently the most. Like a modern Unix operating system, it also has virtual memory, shared libraries, command mounts, copy-execution-write-disk operations, proper memory management, and TCP/IP networks that are shared between executing code.

Linux network function is very powerful, such as you can FTP, NFS, etc. to install Linux, use it to do Web servers, gateways, etc., with the development of Linux, its derived from the application I am afraid even Linus himself is very difficult to think of. The largest single application of Linux is the Internet and intranet servers, covering the specific applications from firewalls to Web servers. According to analysts, Linux has become the second most common operating system on the Web. Other Linux applications 

Even as a desktop operating system, it has a better performance than UNIX, which many users are familiar with. A Linux server that supports 100 to 300 users is no problem, and a Linux print server that supports 200 to 300 network printers is a piece of cake. And it does not care about the speed of the CPU, it can put the performance of each processor to the limit, for Linux, the impact of the performance of the system can improve the main constraints of its bus and disk I/O properties.

In addition Linux and general software is very different, because it belongs to free software, so you can share Linux with friends, you can copy, use it arbitrarily.

5, what is the Linux release? What are the Linux releases?

Vendors like Redhat typically integrate Linux kernel and peripherals, and then release their Linux-based Linux-core packages: typically include a C language and C + + compiler, Perl script interpreter, Shell Shell, The graphical user interface X Window System, as well as the X server and numerous applications, is a complete Linux system known as Linux Publishing (distribution).

Currently the most widely used Linux release is the Redhat company's Redhat Linux, now Netscape, Intel and other large companies to support it, the outlook is good, according to the general view Redhat is also the most easy to use Linux release. There used to be a wide range of Slackware, and now many people are using it, Slackware is slightly more complicated than Redhat, which is mainly in Software installation: Because Redhat use the RPM packaging system, the installation of new software is simple as long as one line of command, And Slackware often to recompile from the source code, a little trouble some. SuSE also uses the RPM packaging system, SUSE is special in its support for the X Window System is very good, Debian is entirely developed by volunteers, based on its own Deb packaging system, but it can also install the RPM package.

6, Linux kernel version and distribution version what is the difference?

Linux version refers to its kernel version, Linus and other people in the ongoing introduction of new kernel, the use of a relatively wide range of 1.2 8, 1.2.13, 2.0, 2.2.x and other versions, the corresponding utilities and application software is mostly GNU or free software.

Beginners often confuse Kernel with distribution. For the kernel version, the current version of the serial number is about 2.4.0. (An even number as a second ordinal indicates that this is a stable version that can be used, such as 2.2.30, while odd numbers are second, there are generally some new things to join, not necessarily very stable such as 2.1.37); compared to the kernel version, the distribution version varies from one type to another, Where Slackware Linux is from 1.0.41 until the most recent 4.0,redhat version is the 7.1,debian is 2.2.x.

The development of Linux kernel is independent of the development of the distribution version, for example Slackware Linux usually has a kernel Source code, as well as kernel Image for many different hardware devices, The most common user needs to master is to update the system kernel technology: the first to obtain the latest version (and must be determined to be stable version) of the kernel source, and then replace with Slackware Linux with the old version of source code, recompile into kernel Binary, New and old updates so that the system core can be updated without reinstalling the system.

7. What Linux releases are on Intel platforms (distribution)?

Mainly red Hat, Slackware, Debian, SuSE, OpenLinux, Turbolinux.

(1) Red Hat

Easy to install is known, the beginner installs this version, encounters the setback the opportunity to be almost zero, if you have been very adept to installs the Win9x, the Red Hat Linux installation must be difficult not to pour you.

Another advantage of Red Hat is its rpm (Red Hat Package Manager); In the past when installing software, the most annoying thing for users is: the software to unlock the compression before the first to create a directory, and then move the software into the decompression, after decompression, some parts may need to move to another directory, When you have to move a project for a long time, it is a chore to do the work. and rpm"Package Manager" On this point, can all the paths to be installed all arranged, when the user untied there. " rpm"the file with the extension, the path file that was set up when the file was packaged is checked first, then, according to the settings in the file, untie the files and send them where they should be; not only that, it also makes installation records, and when the user wants to remove any of the RPM files, the system will reverse install the file according to the installation record, which Absolutely accurate and will not remove something that should not be taken away like Windows.

Red Hat Linux can be said to be quite a success of a product, Red Hat Company has " The official version "(official) for users to purchase, but also provides a free FTP station for the public to download directly, the official version and free download version of the difference is that the official version of the more provide some commercial software and beautifully printed instructions.

(2) Slackware

This is an old-school door Pie, a few years ago, the people who play Linux, almost all with this system. It can be completely "hand-built" the characteristics of personal needs, so many are now the master level of the players are still obsessed with, slackware in the domestic use a lot, may be used to do the server, performance will be better. The latest version 4.0, the installation process has improved a lot, you want to "fully control" the situation of friends can try.

(3) Debian

You will usually see the words "GNU Linux" after the Debian word, which is now recognized as the most structured and well-organized organization, and it also has a package management system called "dpk" (Debian Package), done and Red Hat's " rpm"the same, make the overall document management more convenient. Debian's original code was open to GNU, so it was completely compliant with the open source code, unlike other Linux, which kept a bit of the program code open (Red hat was not open until version 6.0). At present version 2.1, and there is a part of the program designer, the Debian porting to other platforms, so can also be seen on other platforms.

(4) SuSE

This is a very popular version in Europe, and it works with XFREE86 to develop the X Server on x86. SuSE installation can choose to display German or English, it also has its own set of procedures called "sax", can make users more convenient settings, its installation kit also uses RPM mode, so to install, upgrade and remove the program is very convenient, the current version 6.1.

(5) OpenLinux

This is a version of the caldera company, not a very "open" version, the online can download its lite version, but the official version is Money, because the entire suite has many commercial software, so did not provide network download services.

(6) Turbolinux

The kit, developed by Pacific HiTech, has a place in the Japanese market, from installing to using interfaces in Japanese, and at home it has developed a Chinese version in collaboration with Tsinghua and research institutions, creating a Linux trend in the country, 3.0.2 is now available in the simplified version, 3.6 in English version.

8, the Mac platform on which Linux publishing (distribution)?

The main mklinux, Red Hat, LINUXPPC, Turbo Linux, Yellow Dog Linux, in addition to the MkLinux is the official version of Apple, the others are " People in opposition "; However, we have adopted the Redhat company development of the original code packaging, plus some of their own suites, and then launched its own version; This means that everyone's installation is almost the same, for users, this is good, you can save a lot of time to explore.

(1) Red Hat

See the previous article

(2) MkLinux

MkLinux is the development of Apple's version, can be said to be "old", the current version is DR3 version.

(3) LINUXPPC

The current version is 5.0, with the Linux2.2 version core (kernel) and GLIBC 2.1, which supports USB and some new devices that can be installed on the new power Mac G3 model, and LINUXPPC perform more efficiently than mklinux. Compared to MkLinux, LINUXPPC can only be used on the Power Mac of the PCI interface, and MkLinux can be used on all models, the two systems look too much alike, except for the difference between the applicable model and the execution efficiency, the other parts are almost the same, all the executable software is the same.

(4) Turbo Linux

Turbo Linux on the Mac can be seen in version 2.1, it will be installed when the selection window, so that users choose to install MkLinux or LINUXPPC, and then start installing the system, so this version of the installation process is somewhat different, the other content is similar; Turbo The Mac version of Linux is not in culture, and the speed of development is much slower than the PC version, the estimated Mac version has been temporarily "put" on one side, Pacific HiTech Company in full development PC version.

(5) Yellow Dog Linux

It is recommended to be installed on the Mac, IMac, blue and white G3 Power Mac series machine. It has two versions, the server version called "champion", and the version called "black lab", "champion" is the version of the generic user installation, and the "black lab" version has "Parallel Processing" (Parallel Computing Ability: The user can install the system on many Macs, and then let all Macs "work together" things, which can make processing speed very fast. Companies that develop yellow Dog Linux focus on the PowerPC Mac platform, and there is no "Intel platform" Yellow Dog Linux version.

9, RedHat, Slackware and Debian, who choose the home?

There are a lot of Linux versions available on the Internet, and more CD-ROM versions, RedHat Linux, Slackware Linux and Debian Linux are among the most famous of the three releases.

RedHat Linux for Linux beginners, is absolutely the best choice, its perfect system configuration, pre-installed with a wealth of applications, powerful system management procedures, so that users spend a considerable amount of time and energy to obtain a perfect Linux environment, its unique RPM packaging procedures, It also allows users to upgrade the entire system without having to reinstall the Linux system. But its directory structure is complex, system configuration files messy, for advanced users, is not a good choice, at this point Slackware will slightly.

Slackware is not recommended for Debian compared to Debian because Debian differs greatly from the newer Slackware compared to the software version.

So for beginners It is recommended to choose Redhat Linux, while the advanced user to use Slackware seems more appropriate.

10. What are the Chinese Linux releases (distribution)?

The current Chinese Linux distribution mainly includes: Teng map Linux Storm one of the series Redhat Linux6.1, Red Flag Linux, Blue Dot Linux, turbolinux Chinese Version (GB), Xteam Linux (GB)

11, how to get Linux?

Linux source code is public, each version of Linux, including from the kernel to many applications source code, execution files, can be downloaded from the Internet free of charge. You can also get a Linux system by buying a CD or a D CD, and unlike the general software, you can legally share your Linux CDs with your friends, and it's clear that the price for Linux is not high. Linux has many distributions and vendors.

12. What are the famous websites and newsgroups of Linux?

The famous website and Linux online, there are a lot of news about Linux, new software, documentation, links and other information.

Comp.os.linux.announce is a well-known Linux newsgroup that can find many questions and answers about Linux, and the following newsgroups in comp.os.linux.* are also worth looking at:

Comp.os.linux.setup

Comp.os.linux.hardware

Comp.os.linux.networking

comp.os.linux.x

Comp.os.linux.development.apps

Comp.os.linux.development.system

Comp.os.linux.advocacy

Comp.os.linux.misc

If you are slow to access comp.os.linux.*, you can also access local newsgroups, such as the comp.os.linux.* newsgroup in China, which is cn.comp.os.linux.

13. How many users can the Linux server take at the same time access?

There is no limit to the number of users. If it's just for a file server, there's basically no wait time. Network bandwidth is a limitation, and if you use 100BASE-TX, you should feel almost the same as your local disk.

14, what kind of PC can run Linux?

Linux supports Intel's X86, PIII CPUs, and multiprocessor systems that support the Intel MP architecture (and can now be run on Sparc, Alpha, PowerPC, and other CPU machines, even in the Entertainment gaming console Nintendo 64. To be a simple operating system like WINDOWSCE, requires at least 4 m of memory, a single soft drive, the PC's bus: It can be traditional ISA buses, EISA, VESA Local, MCA (all IBM buses), or Intel PCI, Supports most ESDI, IDE, ata33/66/100 hard drives.

Linux can run on Dec's alpha machine, or it can run on Sun's SPARC machines and, of course, run on more than 386 of Intel's machines, and written source code can be compiled and installed directly on a variety of Linux platforms without modification.

The minimum configuration for Linux installation is:

More than 80386 CPU

More than 4M of memory

Hard drive above 80M

Linux can not run on the 80286 CPU machine, less than 4MB of memory machine, if the memory is less than 4MB, can not install, want to run X window, 8MB is the minimum requirements. If you use Linux as a server, you need at least 16MB of RAM, and software like Netscape requires 64M of memory. As for hard drives, from zero to a few GB, preferably more than 500MB space.

15, Linux can support the hardware?

Linux supports the largest number of UNIX systems, supporting virtually all types of display cards and monitors, a wide variety of mouse, almost all types of SCSI devices, most IDE-access hardware, and all SCSI tape drives and QIC-02 tape drives, SCSI CDROM drives and part Eide (ATAPI) CDROM, all SCSI-attached external drives, and Zip drives for the Kou.

Linux supported CPUs are: Intel/amd/cyrix produced x86 series CPU

386SX/DX/SL/DXL/SLC,

486SX/DX/SL/SX2/DX2/DX4,

Pentium.

Pentium MMX

Pentium Pro

K6,m2,k7,cyrix 6x86, etc.

Since the Linux kernel supports the mock FPU, even if the cpu,linux of the FPU coprocessor is supported, only the system speed will drop, especially in the areas of compiling and graphics processing, but now that the Pentium series CPUs have become mainstream, the problem is no longer there.

In addition, Linux2.0 core support for multiple CPUs (SMP), no matter which release version, as long as the core after 2.0, support multiple CPUs.

The method is: before compiling the core, change the/usr/src/linux/makefile beginning smp=1 to Smp=n, n is your CPU number, then make DEP; Make clean; make install; Make modules made Modules_install started, and it worked!

16, what software on Linux? How do I run DOS and Windows programs under Linux? Can you run office2000 on it?

Linux has c program compiler GCC, editing software emacs, graphical interface x-windows, all standard UNIX System Tools (utilities), TCP/IP networks (including SLIP/PPP) and hundreds of applications developed or ported.

Linux has a DOS emulator called DOSEMU, which can simulate DOS and run some DOS applications. Accurate Dosemu is not a DOS simulator, it provides a virtual x86 machine to run DOS, can run Dos6.22 and pure Dos7. It also provides support for VCPI and Dmpi. Dosemu can run the standard mode and the 386 enhanced mode Win98, but the configuration is very difficult, performance is not good, not stable.

Linux can also run some Windows programs, the development of this simulator has progressed, supporting the SVR4 ELF and SVR3.2 coff binary iBCS2 (Intel Binary compatibility Standard) simulation code, can be included as a compilation of the Linux kernel, and, in addition, Some companies offer commercial software (paid, copyrighted), such as Motif,aplixware,wordperfect.

Office2000 does not have a for Linux version and does not work on Windows emulators, and Linux can use for Linux office software such as StarOffice and Applixware office, but they are commercial software.