Friday 27 January 2012 at 09:10 am
Development commands
cc This will run whatever C compiler is installed on the system. On most Linux installations, this will run the GNU C compiler (GCC), which can also be run by typing gcc.
lint Syntax: lint filename.c lint is a C code checker, meaning it scans C code for coding problems. These do not necessarily have to be errors; It also scans for inefficient or non-portable coding techniques. XWindows commands xf86config This runs the configuration utility for XFree86. You want to do this before you run XFree86, so you can set it up (particularly the parts relating to your monitor). xf86config modifies a file called XF86Config, which is the actual X configuration file. (Note that the filename differs from the command only by the capital X, F, and C.)
xf86config is the standard Linux command for configuring XWindows. It's text-based and it asks a lot of questions, but it is the tool that's supposed to be available on every Linux installation. Depending on your distribution, there may be other tools available. In particular, Red Hat has a menu-based XWindows configuration utility called Xconfigurator, which can be run directly from the command line, and is also available as an option from Red Hat's own setup utility. Other distributions may have their own special X configuration programs. xorgconfig Same as xf86config, except this command applies if you're using the X.Org version of X instead of XFree86. xorgconfig configures your /etc/X11/xorg.conf file.
SuperProbe SuperProbe is an uncharacteristically boastful Linux command which simply probes for your video hardware. This is important since XWindows tends to be so dependant on knowing the details of your particular model of video card and monitor. SuperProbe will tell you (or attempt to tell you) the manufacturer of your video card, what kind of video chipset it has, and how much RAM it has. This information is certainly helpful if you don't know it, and it tends to be useful when you are setting up XWindows. xwmconfig Short for X window manager configuration, this command lets you select your window manager for XWindows. XWin comes with Tab Window Manager (TWM), a rather basic WM. Another popular WM is Sawfish.
xwmconfig creates a file in the /etc/X11/xinit directory called xinitrc. This file is actually just a link to another file, and that other file is the X Windows initialization script. For example, the rc file for TWM is xinitrc.twm, and if you choose TWM with xwmconfig, then you will find that the xinitrc file is a link to xinitrc.twm. switchdesk switchdesk lets you select your desktop for XWindows. This is, for example, how you switch from GNOME to KDE, or vice-versa. Do not confuse this with your window manager; twm and Sawfish are examples of window managers. GNOME and KDE are desktops; they are NOT window managers. startx This starts X. (startx is actually just a shell script that calls xinit, the real X initializer. However, startx passes a couple of variables to xinit, so you should use startx instead of typing "xinit" directly.) xhost xhost is the security access control utility for XWindows. It simply sets what clients are allowed to connect to your X system, and which are not. If you don't care about security too much and just want to allow everybody access to your X system, simply type the following command to allow all access: xhost + Text editors ed This is the "basic" text editor which comes with Linux by default. It's a line-based editor, like the old edlin which used to come with MS-DOS before Microsoft realized everybody wanted a full-screen editor. Hardly anybody who does much text editing with Linux uses ed. vi Short for "visual", this is a full-screen editor which is fairly simple to use, and does exactly what you want it to do without any frills. Most people like vi the best.
Note that in Linux, vi is usually implemented as elvis, a new-age text editor that works like the classical Unix vi but is intended to replace it. However, the "vi" command is usually linked to elvis, meaning that typing either "vi" or "elvis" in Linux should work. emacs A big program, EMACS (short for Editing MACroS) is famous for being a highly feature-laden text editor. It has more features than any program needs, and indeed, most people find EMACS too sophisticated for their tastes. EMACS doesn't usually come with a basic Linux installation and must be installed as a separate package. (For some quick info on EMACS keystrokes, check "EMACS Keystrokes", below.) pico pico is a relatively new text editor. Obviously it is not as well-known as vi or emacs, but it has become quite popular in its own right. It's supposed to be easier to use. It uses several basic keystrokes which are displayed on-screen (instead of requiring you to remember them). Newbies may want to try pico first (and last). Debian-specific commands (Debian is a distro of Linux, in case you wondered.) dpkg dpkg is Debian's package manager. It'll unpack Debian binary files (which have a .deb extension.) dselect dselect is Debian's user-friendly package manager. It has a full-screen interface, unlike dpkg, which is a command-line utility.
Directories and files of interest /home/username Every user on a Linux system has a "home directory", their own directory where they're supposed to keep their stuff. This directory is normally in /home/username. For example, if your username is JimmyTheHand, your home directory would probably be /home/JimmyTheHand. (Before somebody asks, the reference to "Jimmy The Hand" is from Betrayal At Krondor. It just came to me as I was trying to think of a random name.) /etc/motd This is the MOTD, or "Message Of The Day". This is the message which users see immediately after they log into the system. (From the name, apparently this is supposed to change daily, but it usually doesn't.) /etc/issue This file gets shown immediately before a login prompt. This is different from motd in that motd gets shown right after anyone logs in, while issue gets shown just before. /etc/inetd.conf This file lists all servers running on the system (that is, all ports which it will receive connections on, and what it will do on them). By default, for example, FTP (port 21) and Telnet (port 23) servers are set up, so people can log in through those. /etc/fstab is your file system table. It lists all the default installed file systems, and the partitions and directories they're on. /etc/inittab stores information on the different runlevels available. /etc/hosts is your system's host table. It stores the names of computers on the LAN. This works sort of like DNS, except that instead of running a dedicated name server, it's just a table of addresses and corresponding names stored in one file. Once you put a system and its address in here, you can use that system's name in place of its address. For example, if you named a computer joe, you could just type "ping joe" or "telnet joe". /var/log is generally where log files go. Yes, all of them. /var/spool/mail This is the directory where everyone's mail on the system gets stored. The person's mail is stored as a file with their username. For example, someone with a username of DogDoo would have his/her mail in a file called DogDoo in this directory. .profile This file, if you have it, exists in your home directory, and is basically equivalent to DOS' autoexec.bat file.
Anything in .profile will be executed when you log in. Each user has their own commands which they might want to run automatically when they log in, so everybody gets to set up their own .profile file. (See also rc.S under "rc.d files", below.) /etc/lilo.conf This file, as you might guess, is your LILO (LInux LOader) configuration. LILO is the program which runs when you boot up your computer and lets you choose between booting into Linux or Windows. (Apparently, however, even if Linux is your *ONLY* operating system, you still need to install LILO to load it. Or so I've heard.) lilo.conf specifies what partitions exist and what operating systems are installed on them, as well as what message to display on bootup and how long to wait for an answer before defaulting to one OS. /etc/isapnp.conf This is the isapnp configuration file. /vmlinuz This file is your kernel. The kernel is the heart of the operating system, the main part of it which loads before anything else. /lib/modules stores your system's modules. /etc/ppp This directory holds your PPP configuration info, including the file pppscript, which is the script used when connecting to your ISP. /etc/resolv.conf lists the IP addresses of the DNS servers to use when resolving hostnames while a PPP connection is active.
/etc/HOSTNAME contains your system's hostname. See the hostname command for more info. /usr/src/linux/Documentation/Configure.help You'll only have this file if you've installed the Linux kernel source code. It lists all the options available during kernel configuration, along with explanations. I *highly* recommend reading this file and using it as a reference if you're re-compiling your kernel, because the re-compilation process asks you a *lot* of questions about what you do and don't want included in the kernel, and most people probably aren't sure about what half of the options mean. /etc/XF86Config contains XWindows configuration information (including what frequencies/resolutions your video hardware can support), assuming you have X installed, of course. /etc/passwd is where all the system's user accounts are stored, along with their (encrypted) passwords. /etc/shadow is usually where the system's "shadowed" passwords are kept. (Shadowed passwords are those stored separately from the main /etc/passwd file for security.) /etc/localtime is not actually a file, but a link to a TZif (Time Zone info) file in the /usr/share/zoneinfo directory, which configures what time zone you're in. /etc/syslog.conf controls what kind of logging is done by the system, and where the log files are kept. /etc/mail/sendmail.cf is your Sendmail configuration file. /etc/group contains a list of all the user groups on this system, along with their identifying numbers. /etc/httpd/conf/httpd.conf is the configuration file for the HTTP daemon (a.k.a. the web server). rc.d files The directory /etc/rc.d contains several scripts which do stuff. The functions of a few of them are listed here. rc.S This is the System Initialization Script. It's run every time you boot up Linux. Like .profile, then, it's akin to DOS' AUTOEXEC.BAT. (NOTE: Don't fool around with this if you don't know what you're doing. Basically, stay away from it entirely, because it runs before any login prompt is displayed, and many programs won't like trying to run without someone logging in first. If you want to make a program run automatically after you log in, it's much safer to use .profile.) rc.modules This lets you specify what modules are loaded on bootup. (Modules might be device drivers or other things which you want to load automatically.) rc.font This lets you choose what font is used for your console. rc.gpm This is the gpm initialization script. gpm (General Purpose Mouse) is the mouse driver for Linux. ~/. files
The ~ symbol represents your home directory in Linux. Thus, these are files which go in your home directory, and which have filenames that begin with a period. (In Linux/Unix, a filename which begins with a period is supposed to be a "hidden" file, which is not meant to show up in normal directory listings and which you are not supposed to mess around with.) .bashrc This is the rc (resource configuration) file for the bash shell. Commands in this file will be automatically run when bash starts. .cshrc This file works just like .bashrc, except it's for csh (the C shell). .login Regardless of what shell you are using, the commands in this file execute when you log in. .rhosts (Again, I wish to remind you that this file goes into your home directory). This lists accounts which you own on other computers. It lets you log into the account (on the machine which stores the .rhosts file) without using a password. It is to be used for your accounts only; Since it is in your home directory, each user has his or her own .rhosts file. This file works with the "r" commands, like rlogin and rsh. Device files Linux refers to all the system devices as file-like pointers in the /dev directory. Here are some of the more important ones: /dev/ttyS0 = COM1 serial port /dev/ttyS1 = COM2 serial port /dev/ttyS2 = COM3 serial port /dev/ttyS3 = COM4 serial port /dev/console = currently selected console /dev/ttyx = virtual console (where x = number of console) /dev/null = data sink (anything sent to here disappears) /dev/fd0 = first floppy drive /dev/fd1 = second floppy drive /dev/hda = first IDE drive /dev/hdb = second IDE drive /dev/hda1 = first IDE hard drive, first partition /dev/hda2 = first IDE hard drive, second partition /dev/hdb1 = second IDE hard drive, first partition /dev/hdb2 = second IDE hard drive, second partition /dev/sda = first SCSI drive /dev/sdb = second SCSI drive /dev/sda1 = first SCSI hard drive, first partition /dev/sda2 = first SCSI hard drive, second partition /dev/sdb1 = second SCSI hard drive, first partition /dev/sdb2 = second SCSI hard drive, second partition /dev/st0 = first rewinding SCSI tape drive /dev/st1 = second rewinding SCSI tape drive /dev/nst0 = first non-rewinding SCSI tape drive /dev/nst1 = second non-rewinding SCSI tape drive /dev/ht0 = first rewinding IDE tape drive /dev/ht1 = second rewinding IDE tape drive /dev/nht0 = first non-rewinding IDE tape drive /dev/nht1 = second non-rewinding IDE tape drive /dev/mouse = mouse /dev/audio = sound card /dev/eth0 = first Ethernet device (usually a NIC) /dev/eth1 = second Ethernet device /dev/tr0 = first Token Ring device /dev/tr1 = second Token Ring device /dev/fddi0 = first FDDI device /dev/fddi1 = second FDDI device /dev/loop1 (and so on) are "loop devices" (see the losetup command) A note on hard drives and IDE devices: The /dev/hd devices are actually IDE devices, not specifically hard drives. If you have an IDE CD-ROM drive, it'll also have an "hd" device name. In this case, don't use a number on the end for a partition (since CDs don't have partitions). Instead, the drive will just use the letter.
For example, usually your first CD-ROM drive is /dev/hdc and you second one (if you have one) is /dev/hdd. Actually, here's a little note on how Linux numbers hard disk partitions... The *partitions* will be numbered from hda1 to hda4 (on hda), while logical drives within the *extended* partition will be numbered from hda5 onward. For example, on my hard disk, my first primary partition is FAT16, the second is my primary Linux partition, and the third is my Linux swap partition. These partitions are labels hda1, hda3, and hda4, respectively, in Linux. What's hda2, then? It's my extended DOS partition. The extended DOS partition has two logical FAT16 drives in it. These drives are hda5 and hda6 in Linux. Confusing? Yes. Also, here's an explanation of the /dev/random and /dev/urandom devices. (The following text was ripped from the comments in the Linux kernel source.) This routine gathers environmental noise from device drivers, etc., and returns good random numbers, suitable for cryptographic use. Besides the obvious cryptographic uses, these numbers are also good for seeding TCP sequence numbers, and other places where it is desirable to have numbers which are not only random, but hard to predict by an attacker. /dev/random is suitable for use when very high quality randomness is desired (for example, for key generation or one-time pads), as it will only return a maximum of the number of bits of randomness (as estimated by the random number generator) contained in the entropy pool. The /dev/urandom device does not have this limit, and will return as many bytes as are requested. As more and more random bytes are requested without giving time for the entropy pool to recharge, this will result in random numbers that are merely cryptographically strong. For many applications, however, this is acceptable. A brief tutorial on using ipchains
The first ipchains command you should know is ipchains -L. This will list all the current rules. (Yes, the L has to be capitalized.) Next, experiment with ipchains -N. This is the command to make a new user-defined chain. For example, typing ipchains -N newchain will make a chain called newchain. After typing it, use ipchains -L to confirm it and see your new chain in the list. ipchains -X is the opposite of -N. Type ipchains -X newchain to delete newchain. Now it's time to do some rule editing. First of all, type ipfwadm. This appears to be some kind of command built into Linux which sets you up with a basic ruleset. After you type it, use ipchains -L once again and notice that your ruleset has gone from three lines to about a screenful. Take a look at the rules that you have; Most of them probably look like gibberish right now, but you'll learn what everything means later. Now let's try learning how to change those rules. The command syntax for changing a rule with ipchains is: ipchains -R chainname rulenum Where chainname is the chain name, and rulenum is the number of the rule you want to change. Note that this command, on its own, does absolutely nothing; It specifies what rule you want to modify, but does not mention what modifications you want to make to it. For now, let's try turning logging on for some rules, so you can see logs of some IP traffic. (Logging is what ipchains is probably used most for anyway.) To turn on logging for a rule, you need to specify the -l switch to ipchains (that's a hyphen and a lowercase letter L, as in log).
Now, you should know that ipchains doesn't actually provide you with a way to modify a rule; Technically, you replace rules, you don't change them. (The R in -R stands for replace.) This means that when you change a rule, you have to specify the *entire* rule's information, or anything that's already there will be lost. You can't just add one part to a rule. Check out the first rule in your ipchains -L output. It should look like this: ACCEPT all ---f-- anywhere anywhere n/a The leftmost column is the rule's target; As you can see, the target in this case is ACCEPT. So, let's suppose you want to turn on logging for this rule. You would use the -R command to replace it with a new one, you'd use the -l flag to turn on logging for it, and you'd also need to specify the target name again, or else it would just be set to nothing. To specify a target name, use the -j flag. So, the complete command that you'd use to turn on logging for this rule is: ipchains -R input 1 -l -j ACCEPT Did you get all that? The -R tells ipchains to replace the rule, "input" is the name of the chain, 1 is the rule number (the first rule in the input chain), -l switches logging on, and the -j ACCEPT part makes sure the target remains as ACCEPT. ipchains logs to /var/log/messages. If you want to check the data it logs, look there. There's more to ipchains than this, but that's the basics; If you want more you can always check the manpage for ipchains (by typing man ipchains of course). Have fun. ipchains' successor, iptables, seems to be remarkably switch-compatible with ipchains. The -L, -N, -X, and -R commands work almost in an identical fashion. Use the -A switch to add new rules to existing chains. (For example, type iptables -A newchain to add a new rule to the chain called "newchain".) The only significant difference, as far as this brief introduction goes, is that iptables does not support the -l switch to turn on kernel logging; Instead, you must specify a targetname of LOG. So to turn on logging in the first rule of the INPUT chain, you'd type: iptables -R INPUT 1 -j LOG Of course, you can type man iptables to get more info on iptables. Again, have fun.
Installing programs in Linux When you get a Linux program, it's usually in a .tar.gz (or .tgz) file, which is a TAR archive that has been further made into a GZIP archive. Before anything else, you must uncompress these archives, just like you need to uncompress a ZIP in DOS before you can use the files in it. The usual way of handling .tar.gz files in Linux is with this command: gzip -cd filename | tar xfv - (Where filename is the filename of the .tar.gz file.) The x option tells tar to extract the archive (it must be the first option). The v option tells tar to be verbose (so it provides more info). Note that newer versions of tar have a "z" option which lets you filter the file through GZIP first, which allows you to just use a plain tar command instead of having to pipe gzip output through tar. So, the new method for extracting .tar.gz files in Linux is with this command: tar xfvz filename Much simpler, isn't it? Again, filename is the filename of the .tar.gz file. Because of all the varieties of different Linux kernels and configurations, rarely do you just download a program and run it, as you would do with DOS. Rather, Linux programs, once you unzip them into some directory, are usually installed using three commands. In the order you should run them, they are: ./configure make make install The "configure" command configures the program to your system in preparation for building it. It creates makefiles in preparation for the make command, and custom-creates those makefiles for your system. Although the configure command can potentially take several parameters (depending on what program you're configuring), you can usually run it with no parameters. The most common parameter used with configure is --prefix, which allows you to specify a directory into which the program should be installed. For example, if you wanted to install the program into /usr/bin, you would type: ./configure --prefix=/usr/bin Often, you might want to install a program into your home directory, and you can simply use the tilde for a --prefix parameter to indicate this: ./configure --prefix=~ The "make" command builds the program, compiling the source code into binary executables. Finally, "make install" actually installs those executables. This is the standard procedure for installing any Linux program which comes in source code form. A final, fourth command is optional: "make clean". This command usually removes any temporary files created during the previous three commands. This is not necessary for the program to function, but it gets rid of the files you don't need anymore and saves some disk space, so it's good practice to run it when you're done.
Tuesday 10 January 2012 at 12:09 pm
Differences between LAN and LAN-to-peer client / server
market participation requirements
expert recommendations of the professionalization of organization costs
NOS Interoperability Requirements
Hardware Differences between LAN and LAN-to-peer client / server
The peer networks or point to point, are based on equality and independence of all workstations connected to the network. Each workstation operating system is installed locally and all the software needed for access to the network. In this type of LAN's servers are not. Therefore, the users of each workstation makers share the resources of your PC (directories, disk drives, printers, etc..) Completely independently.
These networks are often present in areas where the cost factor is very important, the budget is limited and the number of workstations is moderate households (SOHO = "Small Office, Home Office"), small offices, etc.. Virtually all modern operating systems include the software necessary to implement such networks: Windows 3.11, 95 and NT Workstation, Mac OS and OS / 2. The main advantage of point to point networks is cost. No need to purchase an additional computer to perform the functions of the server, nor a network operating system (read Novell NetWare, NT Server or IBM OS / 2). Without a server, it can not fail and undermine the work of the stations connected to it.
But peer networks present some important drawbacks, both in terms of security as in the administration and integrity of information. The comfort that provides centralized management in all aspects (security, resources, etc..) Is simply not possible. From a central server can control access to the network and the resources of any workstation. In the case of point to point network each user is responsible for the administration and security of your computer resources. In to-peer networks, users can unconfigure the operating system on your hard drive (either accidentally or maliciously) so that the workstation can not access network resources can not even boot the local system .
Applications must be installed locally on each hard disk workstations, so when you upgrade, repeat the tedious process. Another serious security problem is that virus infections are much easier to access workstations to-peer networks. The opposite case is networking with one or more servers. On servers you install a network operating system such as Novell NetWare, Microsoft Windows NT Server, IBM OS / 2 or one of the many versions of UNIX.Workstations require a software that allows them to act as a client of the server. Through the server, and passwords are validated in accordance with it, will allow access to particular network resources. The main advantage of this type of network is centralized. The network administrator can control everything from the server: access, install and update applications, perform backups, etc.. Centralization, can reach the point that the workstations do not have a local hard disk to store your operating system.
The greatest exponent of centralization is represented by the Network Computers (NC). These stations, lacking any hard disk and other storage in any case require a server. In this position both the operating system and other applications. Therefore, a CN can not function without resorting to a server. On the contrary, this centralization is also the weakness of this type of network: dependence on the server and the problems associated with a drop of it. However, progress is being made increasingly more on the reliability of the servers, both from the standpoint of the software (network operating system software, automatic recovery, cluster architecture, etc.). And from the point of view hardware (UPS, support for multiple processors, etc.).. Another major drawback is cost, not only for the acquisition of a license from the NOS (network operating system), but a client license for each station to connect to the server.
Regarding the hardware, you should always keep in mind that the minimum requirements of a server will always be higher than a traditional PC, both drives (high capacity and speed, usually SCSI) as in main memory (minimum 64 Mbytes) and processor. Whenever the server power will depend on the number of workstations that served. Summary of differences between client / server networks and point to point network client / server.
Participation in the market for network operating systems
These days of globalization of the economy, the figures presented by renowned companies in charge of the investigation, analysis, evaluation and presentation of data, corresponding to the performance of various market segments, providing an indispensable tool in the decisions that firms make, when making an investment of any kind. Because there are multiple network operating systems on the market, each from different companies, it is necessary to observe the way they are positioned on the buyer's taste. To decide which one is the best for the present and future business, consider their current numbers, as well as a forecast of trends in the years to come.
The representative figures of the involvement of NOS in the market, are taken from research conducted by two of the most prestigious companies in the field of data analysis for computer and information: International Data Corporation (IDC) and Computer Intelligence, who continually polls conducted around the world to know the behavior of the leading products that set the standard in technological development of our society. Figures represent the client / server model has become a standard in the institutions that want a robust and secure, so market research to find the network operating system with these characteristics most required, have increased in recent years.
Novell has been a major player in the networking field since the early 80's with different versions of NetWare, and still dominates more than half the market, where it has great presence. Microsoft had a slow start with Windows NT system, but recently has had a great topping that led him to be in second place behind the giant Novell. With less force comprises the remainder of the market the OS / 2 from IBM, the solution to client / server networks and Apple AppleShare different variants of UNIX such as Solaris, UnixWare and Linux clone. The survival of these network operating systems will depend on the renewal of both productive strategies in marketing in the years to come, as the battle between Microsoft and Novell for supremacy in the market, it seems not wanting to let a third option. Below is the NOS market client / server 1997 (EUA) The networking requirements have resulted in very high demand in the area of the NOS, and the torque requirements of various users have made market trends vary dramatically in a short time. The companies that dominate the industry widely NOS until recently, have suffered the onslaught of competition from other powerful software, like Microsoft, who has been the big winners in the latest polls.Greatly surprised at the Novell and IBM crashes, although the latter had already shown signs of slow growth with passive marketing strategy. The resurgence of UNIX has been a pleasant surprise and has made predictions about the future very unstable for manufacturers of NOS, but on the other hand, the competition to be the best in the industry will greatly benefit the consumer. The following graph shows the percentage growth of NOS client / server worldwide in 1997. The trends towards the year 2000, seems to be going toward a solution with Windows NT client / server systems, surpassing Novell NetWare and UNIX variants, although it is possible a change in the outcome depends on how they go to the new versions of both NT and NetWare, where both claim to be the complete system for the 21st century.
In the market-to-peer NOS, Microsoft with its recent WFW and Windows 95/98, had an extensive domain in this field. The network system of Windows 95 revolutionized the market by coming also included free, has an excellent performance. LANtastic NOS has been the most popular point to point in recent years, but has suffered, like others, competition with Microsoft. Point to Point System 7.5 and later of the Macintosh, is strictly limited to run on platforms of the same type. Here you can see the NOS market point to point in 1997 (EUA). Back to topics in this section expert recommendations order to make a proper selection of NOS, it is important to have an objective opinion of people who have experienced or are somehow involved in the operation of these systems, since when have faced person to one or more of them, have a slightly broader perspective of their pros and cons.
Below is a series of lists that provide the advantages and disadvantages of the three NOS client / server and point to point most popular, based on an arduous collection of opinions, comments and suggestions, professionals from both the commercial and business area, and the academic environment.Advantages and disadvantages of NOS NOVELL NETWARE Advantages: - NDS (Network Directory Service) provides a scalable, global directory, which can be designed for centralized or decentralized. - Excellent management of large-scale networks. - A network operating system hardware independent. - Provides the best print and file system. - Excellent level of security. - Supports applications via NetWare Loadable Modules (NLM). - The vast infrastructure is capable of Novell technical support and assistance for long. - When you discover an error in the recent version of NetWare, Novell makes public the possible solutions for new and existing users. - The larger the network is reduced cost.Disadvantages: - NDS is quite complex to install and manage. - NetWare is losing market share because of the complexity of NetWare 4.1 and NDS. - NetWare platform is somewhat limited in providing services beyond file and print server. - Services such as FTP or HTTP required to purchase additional software from Novell. - The upgrade from one version to another is slow and complex. - Can be expensive for small networks.
WINDOWS NT SERVER Advantages: - Provides a superior general purpose platform. - Supports multiple processors. - Excellent safety. - There are a variety of applications designed exclusively for NT, including freeware and shareware. - Easy to install and operate. - Has a very user friendly interface. - NT is GUI (Graphical User Interface) and OS (Operating System) at a time. - NT is supported by Microsoft, the most powerful software company in the world. - NT is about to enter full support for UNIX. - Has good technical support. - NT is economical to medium environments. Disadvantages: - It's a bit slow as file and print server. - Does not support disc levels. - When you discover an error in the recent version of the system, Microsoft is expected to launch the next version to fix it. - Presents serious problems in very large environments. - As infrastructure grows, the cost of NT increases. - Needs lots of computing resources to run correctly.
UNIX Advantages: - real multiuser system, you can run any application on the server. - It is scalable, with support for 64-bit architecture.- The cost of the different variants of Unix is very small and some are free, such as FreeBSD and Linux. - You can enable and disable drivers or devices without rebooting the system. - UNIX can work with CLI (Command Line Interface). - The Unix kernels are made as needed. - The standards are different suppliers (POSIX). - Provides the ability to perform computer remotely. - This is the best solution for large databases. Disadvantages: - The user interface is not very friendly in some versions. - Requires training because of their complexity, not everyone can use. - Suffers from the lack of commercial applications with important names. - Effectiveness as file and print server is not as efficient as other NOS. - There are discrepancies between different designers and vendors of UNIX.
MACINTOSH Benefits: - Use the Power PC microprocessor, which by its speed and efficiency has a promising future. - User-friendly environment. NOS is the easiest to use. - Powerful capabilities in management and graphic design. - Compatibility with himself. When purchasing new hardware or software, is much less prone to faulty installation. - Security for Internet server. - Plug and Play features. - Longevity. In Macintosh drastic changes to discontinue application architectures, not given. - Easy network management. Cons: - very small market share. - Not compatible with PCs and other architectures. - There are no clones. - Sometimes there are problems with multitasking. An application can prevent other work.
WINDOWS 95 Advantages: - Runs on Intel and compatible. It is the most common. - Very user friendly interface. - Knowledge of the market. - Plug and Play features. - Support everywhere. - Compatible with NT to some extent. - Many applications are available. - Ease of networking. Cons: - The old MS-DOS is still behind Windows 95. - Contains some errors in the factory. - Limitations on file names. - Incompatibilities in filenames Windows 3.1 - is slower than other NOS tasking environments (Macintosh). - Incompatible with scalable versions of application software.LANtastic Advantages: - Handles very good safety levels. (Better than any other to-peer NOS). - It is economical. - Supports more than 500 users. - Easy installation and operation. - Easy interface with Microsoft and Novell.Disadvantages: - You must make an extra expense to acquire it. (Windows 95 and Macintosh software including free-to-peer network). - No support for LANtastic everywhere. - Market share reduced. Back to topics in this section of the organization Requirements When selecting the operating system to a LAN network, the organization needs to have information on certain topics, which may influence directly or indirectly in the successful implementation of the NOS the network. Some of these requirements are: professional staff, knowledge of costs of each NOS, hardware requirements and interoperability of systems installed with similar inside and outside the organization. Professionalization of staff When installing a local area network, one of the things that matter most to the organization, who will take over the management and maintenance of the network. Perhaps there is already a network and trained personnel to handle the current NOS, but it is the first time you install a LAN, it will upgrade the NOS, or will change the current system by a completely different is then required to invest in hiring new staff or train that is already in the company, as each NOS has its own degree of difficulty. We all know that Microsoft operating systems such as Windows for Workgroups, Windows 95 and Windows NT, have the characteristic of being easy to use and learning. The Windows GUI is almost identical in all systems, which facilitates the adaptation of a person who has always worked on Windows and now must be networked. Generally, a person who has used both Windows 3.1 and Windows 95 for single-user tasks effectively, is able to manage with a bit of advice, one-to-peer network based on WFW or Windows 95. To manage a Windows NT network, you need a little more knowledge on what corresponds to networks, but the training is not as strong as in other systems.
NetWare NOS is the most widely used, so most people involved with network management is aware of its operation. For someone who is just beginning, can be somewhat complicated to empathize with NetWare in the first instance, and must undergo training. NetWare version is installed on most medium and large businesses, universities and institutions of all kinds, is the version 3.x. The update to version 4.x is underway in most of them and should be taken into consideration that 4.x includes powerful new features in its operation, such as NDS, which can cause some headaches poorly trained staff on NetWare . It usually requires a network administrator full time. No doubt when they hear the word complexity in networks, immediately comes to mind of many professionals the UNIX system. This thought about that not everyone can use this system, there is some truth and a lot of myth.
Originally, UNIX was not created with simplicity in mind for the user operation, but the need to address several limitations that had other commercial operating systems. It is true that if you want to install a network based on the UNIX system, you must have personnel trained for such work, since they may present problems for those without prior knowledge, to venture with a network of this type. There are many enthusiastic challenges motivate them and work with UNIX can be, but when you have the right staff to manage this kind of network, the results can be surprising. After seeing these cases, the best thing for an organization that wants to reduce costs is to use the staff you already have, enabling NOS in the management of choice, but considering that it may take some time and some mistakes at the beginning , until you have enough experience. If you are looking for efficiency from the NOS is installed, then the hiring of experienced staff is the most viable alternative, except that usually these people apply for relatively high wages. NOS Costs When starting a project, the economic factor plays a key role in the decision to take, and the selection of a NOS is no exception. The cost varies between each NOS, starting from fairly high price to free distribution systems. The pay more for a NOS does not mean it will be more productive for the organization than a low cost, so we must seek that which meets the expectations of the company, trying, of course, that the payment is always the small as possible. Then it presents recent information on the costs of various NOS analyzed in this work.
Windows NT 4.0 (Microsoft)
5 users = $ 809 USD
10 users = $ 1.129 USD
50 users = $ 4.799
USD NetWare 4.11 (Novell)
5 users = $
users = $ 1.095
$ 2.095 10 $
50 = $ 4.995 USD users NetWare 5 ( Novell) 5 users = $ 1.195 USD 10 users = $ 2.190 USD 50 users = $ 5.320 USD Linux Free or $ 49.95 USD (CD-ROM). Unrestricted licenses.
Macintosh (Apple) Update the system 8.5, UnixWare $ 99 (Santa Cruz Operation, SCO) $ 69 USD per unit LANtastic (Artisoft) 1 user = $ 119 USD 10 users = $ 499 USD X users = $ 999 USD LAN Server ( IBM) 1st server = $ 795 USD Each additional license = $ 715 USD
Hardware Requirements
Each network operating system has different hardware requirements to run correctly, if they are not satisfied, the system may not operate or work at a level well lower than expected, causing serious problems in the network. It should then meet the requirements of each NOS to see if it satisfies the current team or need to invest in new hardware. Windows NT 4.0 - 33 MHz 486 processor or higher, Pentium or Pentium Pro, Intel and compatible systems, RISC processor compatible with Windows NT Server 4.0 for RISC-based systems. - 16 MB of memory. - Minimum 125 MB hard disk space Intel and compatible systems, 160 MB for RISC-based systems. - CD-ROM. - Graphics adapter VGA, SVGA or compatible with Windows NT Server 4.0. NetWare 4.11 server: - PC with 386 processor or higher. - 16 MB of RAM (more memory is required depending on number of users, which is loaded on the server, open application number and size of hard disks on the network). - A hard disk with enough free space for the size of the network. (NetWare 4.11 uses at least 55 MB of hard drive). - At least one network adapter. - Cable network. - A CD-ROM for installation. Workstations: - For each workstation must have a network adapter and a computer running the client operating system required. NetWare 5 Server: - PC with Pentium processor or higher. - 64 MB of RAM. - 1 GB hard disk. - At least one network adapter. - Cable network. - A CD-ROM for installation.Workstations: - For each workstation must have a network adapter and a computer running the client operating system required. Solaris 7 - SPARC or Intel Platform 486 (100 MHz) the Pentium. - From 600 MB to 1 GB hard disk. - Minimum 32 MB. UnixWare - Supports PCI systems, I2O, EISA, ISA, MCA Intel Pentium, Pentium Pro, Pentium II and 80486DX. - Requires floppy 3.5 "CD-ROM. - Needs 500 MB to 1GB of hard disk space. - At least 32 MB of memory. 64 MB are recommended. - SuperVGA adapter and monitor with at least 800x600. Linux - Processor Intel 386 and later, SPARC, Alpha, PowerPC, etc. - At least 4 MB of memory. - 150 to 200 MB hard disk space. VINES - PC or SMP (Super-Minicomputer Program) based on Intel. - 16 MB of memory . adapter - Ethernet, Token Ring or FDDI. LANtastic for Windows 95/98 - 486 processor or higher. - 8 MB of RAM (16 MB recommended). - 12 MB hard disk space. For Windows 3.x - 386SX processor or higher. - 4 MB of RAM. - 10 MB hard disk space. For DOS - PC XT or higher. - 640 KB of RAM. - 7 MB of hard disk space. Windows 95 - PC with 486-25 MHz or higher. - At least 8 MB of memory. - 40 to 45 MB of hard disk space. - Display VGA or higher resolution. Interoperability is the ability of different computer systems, networks, operating systems and applications to work together and share information. In an organization, computer resources are often located in departments or separate working groups, often using various network topologies and communication protocols. At higher levels, these systems often use different operating systems and applications .
It is thus necessary to integrate these systems so that everyone in the organization to communicate and share information and resources. All systems of an organization must be integrated, whether DOS-based computers, Apple Macintosh, UNIX workstations, minicomputers , or large computer systems. The network should be seen as a platform of "plug and play ', which connects multiple systems. For this you must use operating systems, applications and hardware products that support multiple networking protocols; also create a network platform underlying communication standards that allow hardware and software work together. Back to topics in this section Back to Home Page Access since December 3, 2000 Find more information on the Internet with this excellent search engine Search the Web. Any comments to: Mr. Manuel Espinoza Curiel me_techpage@yahoo.com Ciudad Obregon, Sonora, Mexico this centralization is also the weakness of this type of network: dependence on the server and the problems associated with a drop of it. However, progress is being made increasingly more on the reliability of the servers, both from the standpoint of the software (network operating system software, automatic recovery, cluster architecture, etc.). And from the point of view hardware (UPS, support for multiple processors, etc.).. Another major drawback is cost, not only for the acquisition of a license from the NOS (network operating system), but a client license for each station to connect to the server. Regarding the hardware, you should always keep in mind that the minimum requirements of a server will always be higher than a traditional PC, both drives (high capacity and speed, usually SCSI) as in main memory (minimum 64 Mbytes) and processor.
Whenever the server power will depend on the number of workstations that served. Summary of differences between client / server networks and point to point network client / servidorRed CostoAlto * Point to Point Economic grandePequeño usuariosMuy SeguridadExcelenteLimitada Number DesempeñoMuy buenoLimitado usoComplejoSencillo Facility * With the exception of Linux and FreeBSD are free.
Saturday 10 September 2011 at 3:27 pm
About ADempiere
The ADempiere project began in in September 2006 as a solution to ongoing philosipical differences with the delvelopment team at ComPiere. Frustrated with commercial aspects and goals at the Compiere project, the developers behind aDempiere sought a more robust and impassioned technology sharing and leveraging effort, rather than concentrating on the freezing of the standards and building of the installed base which may well have been the more important focus at Compiere.
ADempiere is based on JBOSS and the JVM client platforms interacting with databases such as PostgresSql. Sourceforge hosts a client download for Windows which is a package of the ADempiere java based business logic, the JDK and a PostgresSql installation. The ADempiere client can be configured to interface with Linux servers running the Oracle database, so scalability is wide ranging. Instructions for installing the client on Mac, Ubuntu or Fedora are available here.
ADempiere boasts modules for Quotations, Proposals, Sales Orders, Work Orders, Invoicing and Shipping. Also Purchasing, Requistions, Receiving, Vouchering. Also Bills of Materials, Warehouse, Physical Inventory, forecasting, discrete manufacturing, maintenance and costing.
Adempiere also contains General Ledger, Accounts Receivable, Accounts Payable, Human Resources and even boasts of CRM, POS and ecommerce. Likely these are more of restful capabilities to meet other solutions.
Sunday 08 May 2011 at 09:24 am
LAMP is an acronym for an arrangement of Open-Source technologies that fit together with great synergy to provide working database driven systems and database maintaining systems. By definition, wordpress and most shopping cart packages that you can install on a web-server are a LAMP application. Because of the inclusion of Apache in the recipe, LAMP is by definition, internet or intranet related, and these applications would use a browser for GUI purposes.
Modern ERP and CRM applications, even those with heavy internal firewalling and proprietary GUI software have worked for years developing a seperation between the business logic layer and the client interface. For example, the complex liturgy of calculated taxes and deductions related to the gross and net amount of a New York paycheck are the business logic segment of an ERP or accounting program. The pretty looking check on the screen of your Quickbooks program is a graphical representation of the underlying data and calculations. Once upon a time, a programming language shouldered the burden of both tasks.
In the LAMP philosophy, the PHP layer, sometimes also called the Perl layer, can be subdivided again to achieve this result. The Smarty Template system is a convenient way to do this. In the Smarty Template framework, visual elements are written in a high level html with css using only a tag to invoke business logic elements where needed. For example, the gross calculation from payroll hours, which may be the product of regular time, overtime, holiday time, vacation pay, etc. and the series of tax deductions, retirement contrbutions and health plan participation costs may be embedded in the very display of the paycheck with a single tag that instructs a web-page, before formatting the html, to invokde the gross to net.
For Example;
<head><title>Paycheck for employee {{dv_emp_id}} - {{dv_emp_name}}</title></head>
<body>{{bl_pr_gross_to_net dv_emp_id}}
Would start creating a web page (I forget to define the source for the css) but invoke business logic from the payroll modules called gross_to_net for the employee number contained in the dynamic variable dv_emp_id before creating the body of the web browser document.
