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What is a distribution?
When you buy a Linux system, you are actually buying a distribution. That's because Linux itself isn't usable -- it's an operating system kernel, a piece of software that talks to the bare metal of your PC. To make it usable, it's necessary to add other bits of free software; command-line utilities, a graphics system (X11), compilers and libraries (gcc and glibc), and applications.
In the old days (1992-1994) Linux users had to build their own systems the hard way, compiling everything by hand. This was a difficult job requiring considerable UNIX expertise; many components could only be installed if other components were already present. Around 1994, some very small companies and groups of enthusiasts began working on the problem of how to install Linux automatically: the results were the first distributions.
A distribution consists of a collection of software components, usually packaged in the Redhat or Debian package formats, and software that can install them in the correct sequence to produce an operational UNIX- like system. Distribution software includes tools to manage dependencies between packages, so that if you want to upgrade a program that relies on other software, you'll be given the option of upgrading the other necessary items. And, as often as not, distributions are commercially supported -- by the biggest names in the Linux business: SuSE, Redhat, Corel, Caldera, and a host of others.
Redhat Linux 7
Redhat started up as a two man show in 1994; since then they've grown into a multinational software corporation. The basis of this growth is simple -- the Redhat Linux distribution (with a little input from support services based on it).
Since release 6.0 in early 1999, Redhat's distributions have been stratified into the Standard, Deluxe, and Professional editions. The Deluxe edition adds telephone installation support plus the powertools and workstation applications CD's (available separately), while the Professional addition also adds a bunch of server applications (including secure web servers), Apache configuration tools, and a discount off a Verisign certificate (necessary if you want to run a commercial secure web server). Everything in the standard edition is available for free download, but the download consists of at least four CDROM images that occupy 2.4Gb of disk space.
We examined the Deluxe edition of Redhat 7. The box contained a variety of items: a printed installation guide, a 400-page getting started guide, printed release notes, a Redhat resource guide (basically adverts for commercial products available for Redhat), and some Redhat stickers and a keyboard mountable linux commands quick reference. There's also a license booklet that basically says "read the license terms in the documentation for each program". It also contains some CDROM's and a single boot floppy (for use on older machines that can't boot from CD).
The CD's came in a number of packages. First, there was the standard Redhat CD kit; a booklet containing two installation CD's, a source code CD to accompany them (not useful unless you intend to recompile chunks of your system), and a documentation CD. On top of this, there's an errata CD which contains updates to the RPM package management tools -- an absolutely essential component of the Redhat system. (Most bugfixes and updates are provided via Redhat's update page, but these were deemed critical enough to require an update disk.)
If you bought the deluxe or professional edition you'll have Powertools and Applications Library (workstation edition) CD's. The applications library consists of demo versions of a number of commercial items (including the VMWare windows co-execution environment, OpenMail mail server, and ApplixWare) and full versions of some others (such as StarOffice 5.2 and Adobe Acrobat reader). The powertools disk is more useful (unless you specifically want office tools); it contains a load of extra Linux utilities, applications, and tools. Some of the stuff here used to be part of the main Redhat distribution -- for example, the xwpe integrated development tool.
To install, you boot off the floppy disk, with the first CD in the drive; hit return and a boot environment loads then starts trying to detect hardware on your system. You'll need 32Mb or more memory for the graphical installation, but the old character mode installation system is still available. The boot system asks you a number of questions up front (including ones about your local area network's setup for TCP/IP -- if you've got a network card) and takes a stab at configuring the X11 windowing system automatically. Then it offers you a choice of configurations (with the option to choose individual packages to install), and goes and installs everything. As long as all your equipment is in the hardware compatability list you shouldn't have any problems; even if your hardware isn't in the list, it may be possible to get Redhat working with it.
It's difficult to comment on installation managers these days; they're all so slick that they make Windows 98 look clumsy and difficult. Redhat 7's installation wasn't really harder or easier than any of the others -- the usual caveats (autoconfiguration of X11 can be tricky if you've got an unusual video card, autodetection of your sound card may fail if you've got an odd one, WinModems not supported) apply.
In use, Redhat 7 feels like Redhat 6.x; it's a solid, stable Linux system, administered via the linuxconf administration tool and the older Red Hat control-panel tool, both of which are introduced in the getting started guide. Left to its own devices, a workstation install will set up the gdm login manager, which gives you a graphical login prompt and a choice of desktops (with GNOME being Redhat's preferred one, and KDE 1.2 an option).
Under the hood there's a new version of the RPM package database system. Due to relaxations of the ITAR export control regime, Redhat now includes the OpenSSL encryption library with 128-bit encryption enabled; the OpenSSH secure remote login system, and the Kerberos authentication system. All packages have been upgraded so that when the 2.4 kernel is released, Redhat 7 will support it. The hardware management system can now support USB mice and keyboards, and the X Window system has been updated to XFree86 4.01, (including new drivers and support for multiple monitors). There are some additional graphics drivers (including support for the Matrox G200 and ATI Rage 128), and 3DFX support for other chipsets using the GLIDE library. There are also tools for monitoring and configuring the kernel, firewall setup, IDE disk drive tuning, and the USB system.
Redhat are trying to harmonize their distribution with the requirements of the Filesystem Hierarchy Standard -- a standardized layout for Linux systems that a variety of distributors are trying to converge on. FHS is important; it fosters application portability and makes it easier for administrators to move between distributions.
On the minus side, Redhat upgraded the gcc compiler to release 2.96. This is a non-standard development version of the compiler; it breaks compatability with the kernel source, so that a different version of gcc (2.95) is required to rebuild the kernel.
SuSE Linux 7.0 comes in two editions; the personal edition and the professional edition. The personal edition comes with 3 CD's, a quick install guide, applications manual, configuration manual, and boot floppy, and includes 600 applications. The professional edition occupies 6 CD's (or a single DVD), and adds a reference manual and roughly 1300 additional programs.
Installation requirements are similar to Redhat 7; 32Mb for the graphical installer. SuSE 7.0 also requires a minimum 486DX processor, in contrast to earlier releases that could run on 386-grade processors.
The graphical installation kit for SuSE 7.0 has a similar user interface to Redhat, but the similarities stop once you've partitioned your disk, selected a system configuration to install, dinked with the packages, and finished swapping CDROMs. At this stage, both distributions ask some pointed questions about hardware and network configuration, and the differences show up. SuSE has options to configure printing and sound during installation and does a fairly good job of detecting sound cards; in Redhat you need to run the control panel post-install to set up these subsystems. SuSE and Redhat both use different tools to configure X11; my impression is that SuSE's hardware compatability database is more extensive, certainly with respect to monitors. On the other hand, SuSE doesn't offer to set up support for Kerberos (a security protocol used for authentication of user logins on large networks).
Like Redhat 7, SuSE 7.0 uses the Linux 2.2.16 kernel version -- the most recent stable release of 2.2 -- although it's ready for 2.4 when it is released (due December 2000). Unlike Redhat, SuSE have been a little adventurous with filesystems. The /boot directory (where Linux distributions keep their boot kernel image and associated boot-time kit) is a separate filesystem. SuSE provide support for the new (experimental) ReiserFS filesystem type, including putting the root ("/") filesystem on ReiserFS. Normal Linux distributions use the ext2 filesystem; ReiserFS is a replacement for ext2 that is more efficient at storing lots of very small files, and that can recover especially rapidly after a crash.
There's also a /usb filesystem -- this is a virtual hierarchy of devices that lets you see USB hardware plugged into your machine, ready for the 2.4 kernel's improved universal serial bus support. This is particularly useful for removable USB media (such as Zip drives or floppies).
Both Redhat and SuSE support use of LVM, the logical volume manager -- LVM lets you concatenate multiple physical volumes (hard disks) into a volume group; you can expand an ext2 filesystem on one disk by adding volumes to its volume group and using the resize2fs program to grow it into the newly added space.
A number of things have changed since SuSE 6.3, the previous release. Earlier versions of SuSE relied on the commercial Open Sound System drivers for sound support. SuSE 7.0 now has support for ALSA, the Advanced Linux Sound Architecture, a set of open source drivers intended to replace the old open-source version of OSS. There've been other changes, too. SuSE 7.0 comes with XFree86 4.0; this is configured using the SaX configuration tool, which has been updated to cope with the new X server (and to cope with multiheaded operation -- one desktop with multiple monitors). SuSE have also added TrueType font support to this release; in conjunction with StarOffice 5.2 (included) and KDE 2.0 beta (also included) it makes for a spiffy office desktop system.
SuSE is the first linux distribution to make a point of support for blind users. In addition to shipping with a demo version of IBM ViaVoice speech recognition software, SuSE 7.0 includes a blinux daemon designed to provide support for braile terminals. Blinux is a whole host of tools for working with Linux for the visually impaired; this is the first time braile support has shown up in a mainstream linux distribution, and in conjunction with a speech synthesizer, the EmacsSpeak extensions, and possibly speech recognition tools makes SuSE the preferred current distribution for the blind.
The YaST administration tool has also been updated, with the addition of the YaST2 graphical version. As with Redhat, SuSE attempts to follow the FHS specification for filesystem layout. However, YaST throws some surprises into the mixture. Normal Linux systems with SysV-style init scripts execute a series of scripts stored in the directory /etc/rc.d/init.d each time the system changes "run level", in accordance with an elaborate set of symbolic links (stored in various directories corresponding to each run level -- for example /etc/rc.d/rc3.d/ for run level three). SuSE leaves these scripts in place (for conformance with FHS), but doesn't run them! Instead, the scripts are executed from /sbin/init.d, the links that trigger then are stored in /etc/rc.d, and the whole thing is configured by a script that YaST manages. (This is how YaST controls every aspect of a Linux system's startup.) Everything is configured from /etc/rc.config, and if you want to disable YaST and control SuSE Linux the traditional way you can switch it off by setting the flag ENABLE_SUSECONFIG in here.
SuSE Linux 7.0 Professional includes a number of commercial application demos including VMWare, Adabas D (database), the VShop e-commerce server, Open Motif, and IBM ViaVoice speech recognition.
Support for SuSE Linux 7.0 Professional seems marginally better than for the equivalent Redhat product; 90 days of installation support is provided, but SuSE offer support via telephone as well as email and fax. There's also a support database.
There's not a whole lot to choose between SuSE and Redhat flavours of Linux. Both are robust, complete, RPM-based distributions. SuSE seems to include more packages in their "professional" release, until you count the powertools and applications CD's that Redhat bundle as extras. However, SuSE has the edge with release 7 -- Redhat's shipping version of gcc is unable to compile the kernel, while SuSE is more standardized. The differences will fade as Redhat release updates, but for now SuSE has the edge. About the only point where SuSE isn't in front of Redhat is that there's no equivalent of the Red Hat Network or the up2date utility yet.
Storm Linux 2000
Storm Linux is a newish commercial distribution based on Debian Linux, the distribution formerly put together under the auspices of the Free Software Foundation. As such, it uses the Debian packaging system instead of RPM, and Storm's own SAS administration framework.
The box contents of Storm Linux 2000 Deluxe Edition are eerily similar to those of Redhat or SuSE. The user's guide is a trifle thinner, and there are less silly stickers to apply to your PC's case, but the rest of it consists of the same gatefold packet of four CDROMs (with a voucher to send off if you want the source disks), a boot floppy and a driver floppy, details of the support deal. (Which is sixty days of telephone support and ninety days of email support for installation.)
Debian has often been seen as unapproachably difficult to install -- but very easy to maintain afterwards. It's less often used as a platform for metadistributions, although other companies have done so (most notably Corel). Storm Linux is based on Debian Potato (release 2.2) with various extensions. The installer starts up in text mode and unlike SuSE and Redhat forces you to accede to a license on screen before it will proceed. (However, the license terms given are unalarming.) Storm then attempts to identify your mouse and keyboard, select hard drive type and installation media (hard disk, CDROM, or network via NFS or FTP), and start a graphical installer similar to those of SuSE or Redhat (unless you specifically want to stick to the text mode installation).
Storm Linux, like Caldera OpenLinux, incorporates a version of Partition Magic. This runs under Windows and allows you to dynamically downsize a Windows partition, creating room to install Linux side-by-side with Windows. This is a sensible idea, and although experienced users can do the same job using a Windows disk defragmenter and FIPS, it really makes the job of installing Storm Linux easier for a casual user.
Package selection is interesting; unlike the other distributions, Storm's installer explicitly distinguishes between X-based and non-graphical applications, and between client and server network packages. On the other hand, modern distributions have hundreds to thousands of packages; the traditional two-level selection dialog that Storm uses is a little inadequate at selecting these, and even with the brief descriptions included it's possible to miss something essential out or to screw up by adding utilities you don't need. (To be fair, this shortcoming is common to all the distributions in this review, and Storm, being Debian-based, is better at resolving this sort of tangle after it's happened.)
Towards the end of the install process, you'll be asked which desktop environments and window managers to install. As with Redhat, Storm uses the gdm graphical login manager to start your session. On the desktop, everything is slightly more standardized than on Redhat or SuSE -- for example, there's a default background wallpaper in Storm's copy of KDE, along with icons to fire up the SAS administration tool, and the K menu has an option to hierarchically launch any Debian application installed on the system. In use, SAS looks fairly similar to YaST 2, and provides a similar range of setup options; Storm configures sound support using the standard OSS modules. The major difference from YaST is that SAS explicitly prompts for a login and password and a destination machine -- unlike YaST, it's a distributed management tool that can allow you to remotely configure other Storm Linux systems. It's still embryonic when compared to enterprise management tools like CA UniCenter, but it's moving in the right direction.
Control of installed packages is carried out via the Storm Package Manager, another graphical front end to apt-get. This has the nice feature of being able to install packages (and their dependencies) directly via ftp as well as from CDROM media; it's a bit like gnome-rpm with better dependency tracking. While this sort of tool takes a bit of getting used to, it's extremely powerful -- tell SPM to install a package, and it will ensure that any programs or libraries it depends on are brought up to date, and will download the necessary updates from CDROM or over the net as necessary. In addition, there are a number of commercial demos and optional packages on the fourth CD; interestingly, some of these (notably StarOffice) have had their installation routines customised so that they appear as entries in the Debian package database and install desktop icons under KDE. There's also a bonus CD in the box -- a copy of "Heroes of Myth and Magic III", ported to Linux by Loki.
Storm is Debian-based; there are certain differences in layout from an RPM- based distribution. For one thing, virtually all configuration files go in /etc; this means that /etc seems somewhat more crowded. The init script layout is different (less hierarchical than Redhat's SysV-style system) but still recognizable. The system logfiles are still stored in /var/log, but their layout is radically different. Meanwhile some software packages are different. Debian places an emphasis on stability and reliability; maybe that's part of the reason that Storm uses XFree86 3.3.6 as it's X server rather than the newer (but less stable) version 4.0.
There's just one area where Storm is markedly inferior to Redhat or SuSE: bugfixes and updates. There is virtually nothing on Stormix.com about security alerts and update patches -- however, this isn't quite as bad as it sounds. Because Storm Linux is basically a dressed-up Debian metadistribution, any problems with Storm are either their own software (the installer, SAS admin utility, or SPM package manager), or part of Debian Potato. You can find extensive updates and alerts for Potato along with details of software upgrades to fix them. By using SPM to grab new packages from ftp.debian.org or a similar up-to-date Debian archive, you can keep your system secure.
The usual question any reviewer has to answer is, "would I want to buy this?" Storm Linux 2000 is a minority distribution that nevertheless compares favourably with the big guys (both Redhat and SuSE are multinationals who've been in the business for more than five years and employ more than five hundred people). It uses the Debian packaging system instead of the Redhat RPM mechanism. Its system administration tools are different from, but very similar to those of Redhat and SuSE. But is there anything to commend it over and above the others? Anything that makes it unequivocally better?
I'd have to say no -- but the negative answer runs both ways. Storm Linux 2000 is certainly the equal of the other distributions, and as long as they keep to the straight-and-narrow path of producing a value-added Debian distribution with installation support and a few extras it's going to leverage the big advantage of Debian: superb upgradability. If you're blind or speak German as a first language, SuSE is your distribution of choice: if you've been running Redhat since the Mother's Day (2.02) release, Redhat is the one true Linux. And if you want to play with Linux on a Windows machine and need to dink with your partition table without erasing Windows, the bundled Partition Magic tool may tip the scales for you.
Otherwise, if asked to choose between these three distributions in the absence of overriding special needs, I'd have to flip a three-sided coin. They're so close that there's not a lot to choose between them: even the relative page count of the user's guide doesn't amount to much when you consider that all these distributions come with a couple of hundred megabytes of online documentation. Any one of these distributions will make a fine server platform and a good desktop system, and it's a credit to the Linux distributors that they're all so even in quality.
Caldera Technology Preview 2.4
Caldera Systems' distributions have targeted the corporate market from the start, and they've been notably conservative in their integration of new technology; their current eServer 2.3 release lags behind Redhat, SuSE and Debian for example, in using an older version of glibc.
However, the Caldera Linux Technology Preview release is a different species of animal. This distribution is aimed squarely at the bleeding edge enthusiasts who want to evaluate or hack on new technology. It says on the box, "product is for developer testing and to preview this upcoming open source technology: not recommended for use in a production environment". They're not kidding. The current LTP repease came out in September 2000 and is based on Caldera Open Linux 2.3 -- but upgraded with a whole raft of new technologies.
Like SuSE and Redhat, Caldera Open Linux is an RPM-based distribution. It follows the FHS standard fairly well, and is in fact so compatible with Redhat that it is possible to stick an Open Linux 2.3 CDROM into a system running Redhat 6.0, boot from the install disk, select the "upgrade" option, and end up with a Redhat box that's been upgraded and turned into an Caldera system. This doesn't make Caldera a flavour of Redhat, though. Caldera have spent time and energy on integration, ensuring that everything that ships on their distribution is rock solid, because that's what their target customers expect. Caldera have traditionally used KDE as their desktop, and they've put a lot of work into developing the Lizard graphical installer (which is rather nicer to work with than any of the others in this review) and the COAS administration system. However, Open Linux isn't a kitchen sink distribution; it contains fewer pre-packaged applications in a typical installation. In use, Caldera Open Linux 2.3 (in either of its flavours -- the eServer server edition or eDesktop workstartion version) feels like a polished, solid version of Redhat 5.3 with KDE 1.1 as a desktop.
The LTP release takes Caldera into new territory. Glibc has been updated to 2.1.91, XFree86 to version 4.0.1, an early beta of KDE 2 is included, and the kernel is a test prerelease on version 2.4. Given that it had a three month lead over the other distributions in this review, this is fairly impressive: it's the Caldera equivalent of a Redhat rawhide development release, only boxed with binary and source CD's, a boot floppy, and a slim installation guide.
As you'd expect some things were touchy -- very touchy. Unlike the other distributions in this review, X11 seemed to have difficulty with the video card in my test machine: the Lizard installer detected it correctly, but the X server provided didn't want to know. (If you experience this problem, one way out is to install an earlier Caldera release (say, 2.3) and upgrade using the LTP disks.) Once installed, the system worked pretty much as expected (albeit without X), providing an early development snapshot of the 2.4 kernel and the tools necessary to recompile and develop it.
Caldera LTP comes with exactly as much support as you'd expect, i.e. none at all: however, if it's anything to go by, the production release of Caldera 2.4 (early in 2001) will be a solid, reliable kernel-2.4 distribution based on RPM, comparable to a stable installation of Redhat 7 with the new kernel in place. With their eServer offering Caldera are clearly targeting the server market, and if LTP finds its way to stability they deserve to be taken very seriously.
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