Back to Newsletters DAVROM CONSULTING Newsletter - Issue # 10 - Dated: Sun May 12 22:33:52 EST 2002 From the desk of David Clark Well here we are with issue 10 of our newsletter and I would like to extend a warm welcome to those who have just started to receive copies of the newsletter. We have taken on quite a few new readers since our last issue. The past month's support has been a mixed bag of issues and we have also recently been speaking with IBM concerning our supporting AIX (IBM's UNIX platform). DAVROM is able to assist in supplying customers with IBM RS6000 systems as well as AIX support. This coupled with our existing focus on IBM Intel servers for Caldera OpenServer, OPEN UNIX8 (and Unixware7) and Linux (Caldera and RedHat), will help us provide customers with high availability, robust systems. Once again in this issue, we have provided a link at the top of the newsletter if you prefer to read the HTML version. I would like to thank the reader for their time in reading this newsletter. David.M.Clark UNIX is UNIX I often have been asked over the years what the difference between the various UNIX platforms actually is, how hard is it to swing between different versions, and is Linux different to UNIX. Over the years if you stay in the UNIX field you are bound to work on a variety of UNIX platforms. My background is SCO with Xenix (SCO's first UNIX) through to OpenServer and Unixware, but I have also worked on and supported: Dec Ultrix & OSF, SUN Solaris, Dynix, HP-UX, Interactive UNIX, NEC Astrix, AIX, Free BSD, Linux (various mainstream versions). From this list you see that Linux "is" UNIX - if you know a UNIX platform, coming to grips with Linux is not too difficult and as I did, you will find bits that you love over your preferred UNIX, and bits you don't particularly like. For me, I prefer SystemV printing but Linux uses LPD (BSD printing) so .... I adjusted. The fundamental commands are the same (cp, mv, ls, cat, more, sed, awk, tar) and are located in directories such as /bin, /usr/bin. Depending on what packages you include in your installation, files also populate directories such as /etc and /usr/local. Other than some location differences (such as where the "rc" startup scripts live and where the kernel building files are stored) most UNIX systems are not hard to navigate around. That being said the /dev device names are often different between UNIX systems and there are several different names for the default tape device for example: rct0, rStp0, rmt0, mt0 This coupled with different administration utilities and some different filesystem layouts does make UNIX versions different enough to warrant caution when attempting to do major changes on a UNIX system. For run of the mill administration, there is not too much to worry about except to be aware that as mentioned earlier, there are different system admin utilities that help you create users, printers, setup ports, modify network and system parameters - some examples of these are: scoadmin for SCO, linuxconf for some Linux, Webmin for Linux, Smit for AIX, SAM for HP-UX. The fundamental elements are mostly the same and UNIX systems design ranges from AT&T SystemV to BSD (Berkley) and over the years you see a merging of both. Some of the differences between the AT&T and BSD (aside from the West and East coast of the USA) is the location of where they put their files other than /bin, /usr/bin and /etc. Printing, as mentioned earlier is one example of quite different locations of files/directories: BSD uses a configuration file called /etc/printcap and spooling to /var/spool/lpd, AT&T SystemV uses interface scripts and spools files located under /var/spool/lp. The unifying factors of UNIX (that which has given us the Internet we know and use today) lie in networking with such protocols such as TCP/IP and its many overlaying network protocols and standards such as SMTP, POP, PPP, Slip, Arp, Rarp, Telnet, Ftp. The use of Apache, Squid and Samba are commonly shared programs which aside from which directories they actually live in, are standard across the UNIX platforms. It is at this point I would quote what I say to people when asked the various UNIX platform question - "Yes, they are fundamentally the same, but there are some distinctive differences and this is due to the multitude of vendors who have embraced this robust and stable operating system." Lone-Tar - how good are your backup scripts An awesome product that I had the pleasure of being introduced to quite some years back is Lone-Tar from Cactus International. Lone-Tar offers a simple to install and manage automated tape backup and recovery system that protects your system in the event of the unspeakable..... While we write and install scripts in UNIX/Linux, there can be no real guarantee given that these scripts may be affected by some condition that affects the shell environment executing the script. I have lived to see systems that should have been backing up - actually aren't or at least aren't backing up that very file/directory that you need to restore. Lone-Tar offers a great verification process that allows you to keep a finger on the pulse of how your nightly backups are faring and has a supoerset of products that cater for network backups and enhanced crash recovery tools. Lone-Tar is supported on all of the mainstream UNIX platforms including Caldera/SCO OpenServer, Caldera/SCO Unixware, AIX, HP-UX, SUN Solaris, OpenLinux and DG-UX - and many more. Please contact DAVROM CONSULTING if you would like to find out more about Lone-Tar for your backup solution. Some quick bits Caldera has announced its roadmap for Caldera Volution Manager to be expanded to support remote management of Windows, AIX, HP-UX and Solaris systems and beta testing is currently under way for IBM and SUN. RedHat 7.3 has now been released and offers progressive updates to the kernel, KDE, Gnome, Apache and have integrated Evolution client (e-mail, calendar, contacts). Tech Tip Telnet testing ports: There are times when telnet can help you determine if a particular TCP/IP network port is open for network communication. One example that you can test quite easily is to see if port 25, the SMTP port, is communicating on your mail server (or even your local UNIX server). This can be done by: telnet 192.168.1.1 25 where 192.168.1.1 is the IP address of your UNIX/Linux/E-mail server. You should see dialogue similar to: Trying 192.168.1.1... Connected to 192.168.1.1. Escape character is '^]'. 220 davrom.com ESMTP Sendmail 8.8.8/SCO5 ready at Sun, 12 May 2002 21:36:25 +1000 (EST) Here you can simply use the Ctrl-] (control-]) to close the connection. This is an example output showing that the server 192.168.1.1 is able to exchange e-mail and if you know the actual input expected by SMTP, you can send e-mail through this server (conditionally). Another handy use of telnet-ing to ports is to see if terminal server or network printer ports are working (Stallion ePipe or HP JetDirect for example). Back to Newsletters 
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