An Evaluation of SCO Unix Open Server 5.0

by Paul Gampe

When Computing Japan asked if I would be interested in evaluating a copy of SCO's "Open Server 5.0" Unix release, I leaped at the opportunity. My previous employer used SCO Unix exclusively, and that was why I became an SCO ACE (Advanced Certified Engineer). Since coming to Japan, however, I've been working with nothing but HPUX, Linux, and Solaris (various flavors of Unix produced by different vendors).

To write a review, I decided to pick a real-world application for which a customer of ours (TWICS) would be likely to use SCO Unix, such as building a firewall. While this application does not give SCO Unix the opportunity to show off its strengths in NetWare and Microsoft Server interoperability, it does allow SCO Unix to compete as an operating system (OS) by itself. For a firewall, that's exactly what you want from an OS: one that's as secure as possible.

As a test, I chose to build a multi-homed, two NIC (network interface card), application layer gateway firewall, using SCO Open Server 5.0 and the TIS Firewall Toolkit. In retrospect, each step of the installation and construction presented (to me, and I hopey to the reader) a good perspective for evaluating the various components one should look at when deciding on an OS.

Installation
With any PC-based OS, the initial installation can be most enlightening as to just how varied and incompatible the Intel-based PC world can be. I used a 90-MHz Pentium system with 16MB of RAM and a 2GB hard disk as a test machine. The all-Intel chipset motherboard presented no problems, and after about 5 minutes searching the SCO Web Site, I found an updated set of instructions to get the ADPTI CD-ROM driver loaded.

To SCO's credit, the installation (from one boot floppy disk and CD-ROM) then proceeded without a hitch, and was done in 30 minutes. Although I choose a minimal feature set and loaded little more than the OS and some file utilities, included on the CD-ROM were NetWare file and print server packages, the WABI interface for running MS-Windows software under Unix, and Japanese-language runtime environment and utilities.

While searching for the ADAPTI driver instructions, I came across a reference to a series of 3Com network cards that had compatibility problems. Since I had not bought any network card, I noted the serial numbers to ensure not buying a problem card. No such luck! I choose the 3Com 100/10MB 3C590 Combo for its versatile interfaces, but despite having checked the serial numbers on the packages, I ended up with two of the 3Com cards that had driver problems.

Stuck with a small investment in hardware, I e-mailed SCO to ask if they had any plans to release a driver for this particular card. After an exchange of e-mail, with both the US and Japan SCO offices, a working driver was e-mailed to me within a week. My compliments to SCO. Compared with the service I'd grown used to from other Unix vendors, I was amazed to even receive a reply.

Once software has been put on CD-ROM, it's quickly out of date. One of the best things about SCO is that they offer online documentation, and links to the latest patches are quickly available from both SCO's FTP and Web sites.

With SCO Unix, almost every aspect of administering a server is covered in a menu-driven interface that runs under both terminal and X-Windows displays, using SCO's own Visual Tcl scripting language. I've worked with SCO for several years now, and it has been a pleasure to watch a series of disjointed, incompatible programs and interfaces being melded into the unified front-end that SCO Administrator presents.

When running Unix on a PC, it is critical that version control and software compatibility be managed properly. Unlike Sun or HP Unix, where the hardware is manufactured by the same vendor who writes the software, a PC-based Unix has to stay abreast of a huge range of hardware devices.

This is one thing that puts SCO Unix head and shoulders above any other PC-based Unix. SCO Unix has used its long history of PC-based implementations to build a solid, user-friendly software management package. Since the custom Software Management package runs under the SCO Administrator front-end, there is no learning curve to familiarize yourself with the interface. A comprehensive menu set lets you load, install, or rollback patches, choose feature sets, install licenses, and much more.

Building software
The TIS Firewall Toolkit (worthy of a review itself) is one of the best free packages available on the Net. It is a series of small proxy programs for most of the common Internet applications HTTP, Telnet, etc. that can be downloaded off the Internet and built from source.

I realized that I did not have a compiler for SCO. The company sells the development kit as a separate, feature-rich (but expensive) product. In searching the Net, though, I soon found a set of GNU compiler binaries and SCO headers and libraries, all downloadable from the SCO FTP Archive.

The TIS Firewall Toolkit, one of the better source distributions, has good support for most flavors of Unix, and will compile on most platforms. My suspicions were confirmed when I found no special support for SCO; the source had been ported to HPUX, Sun, Solaris, AIX and Linux but not SCO. In general, this is what I find with most packages I download off the net. While it has an impressive stronghold on the PC-based Unix Server market, SCO has a hard road ahead if it wants to penetrate into the Internet Server market.

Porting all the proxies took me about a day. Unless you are familiar with Unix System V, and the ins and outs of PC-based kernels, I would not recommend it. This is a big drawback if you are used to building software from source, which I would certainly advise for a firewall if you have the opportunity. Also there are fewer Internet applications released for SCO (though this is changing).

Linux, SCO, and other PC alternatives
When people talk about PC-based Unix these days, Linux is bound to be mentioned. Given the choice, I personally use Linux, and I consider it one of the great fruits of the cooperative Internet. Linux can be a serious server platform, although you have to be dedicated to the OS to achieve this. You can either subscribe to every Linux security mailing list and newsgroup, and hope nothing occurs when you're asleep, or let a vendor share the responsibility of securing and maintaining your operating system.

In conclusion, if you are an IT manager looking for a midrange server, it would be worth your while to take a good look at SCO Unix. SCO offers the security and reliability of a mature Unix distribution, and the ability to integrate it into your existing NT/NetWare (even Solaris) commitments.

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