– By Dylan Griffiths –

The Linux kernel is the center of every Linux distribution. It is the foundation upon which the userland (the programs and environment you use to interact with the system) is built. The source code which goes into it is very special — any bugs it has will affect every part of the system, perhaps even destroying the work of the user. How do changes happen inside of it? How are decisions made about the direction that the kernel will take?The Linux kernel is split into many parts. The largest division is that of the core kernel code and the device drivers. The core kernel code is divided further into subsystems. Some subsystems contain architecture-specific code, whereas most device drivers are not architecture specific. By the kernel being divided in this way, many people can share the work of maintaining the kernel by watching over specific parts. Each device driver has a person who is responsible for it; each subsystem of the kernel core has a maintainer which monitors its development.

The various programmers working to maintain the kernel are in a loose hierarchy. More experienced programmers, who have contributed more and have volunteered for this responsibility, are assigned more important jobs. The ultimate authority over all of these programmers is the official tree maintainer. As of this writing, they are: Linus Torvalds for 2.4.x, Alan Cox for 2.2.x, and David Weinehall for 2.0.x. The official tree maintainer is like the director of a play — they assign tasks to the other programmers, sometimes giving examples of the direction they wish the code to go. They work to make the kernel match their vision of what it should be.

You may be wondering how a tree maintainer decides on a direction for the kernel; where their vision comes from. It comes from the users. The users ask for features, report bugs that interfere with their work, and generally provide feedback about what the kernel is doing for them. Based on this, and personal motivation, the tree maintainer decides on a set of concrete goals for the kernel. This is their vision.

The direction of kernel development is not static throughout the life of a specific branch of the code. As the needs of the users change, the goals for the tree change. The discussion of these changes takes place on the Linux-kernel mailing list. The list receives almost all of the public discussion between the various developers, as well as general bug reports, feature requests, and patches. Averaging 200 messages a day, it’s not for the faint of heart.

The vision for the 2.4.x tree involved fixes and improvements to the VM subsystem, expanded scalability in enterprise environments, increased portability, and better efficiency. These changes were motivated by the humiliating mindcraft benchmarks of 1999, as well as a desire to give enterprise Linux users the ability to use all their big iron with Linux. Over the course of the tree’s development (the 2.3.x series of kernels), changes not directly related to Linus’ goals for the tree were accepted because they cleaned up code, addressed misbehaviour of code, or paved the way for future code cleanups.

Over the course of the development series, some conflicts arose as well. Andrea Arcangeli and Rik van Riel both had ideas about how the virtual memory subsystem should be designed. Alan wanted to see whose approach to improving the VM was more effective in his AC branch of the 2.4.0-test series. The solution was to have both men submit their patches, and release two versions of the next AC test kernel. The most stable patch was then selected and included in the next release. This process was repeated a few times to give a fair chance for competition between the programmers. The eventual winner was Rik’s algorithm. Linus merged in the patch from Alan’s AC tree, and it became the official VM patch going into 2.4.x’s stable release.

The Linux kernel is one of the larger Open Source projects around. The 2.4.1 kernel is a 24 megabyte tarball; expanded, the source is over 100 megabytes in size. This is quite a growth over the original source released onto usenet in 1991 by Linus — that kernel was half a megabyte in size uncompressed!

By harnessing the ideas of the developers and users, the development process of the Linux kernel has allowed it to eclipse many traditional operating systems in performance and reliability. This process, which emphasizes reliable code and correctness over the feelings and politics of individuals, is an essential part of the success of Linux.

Catherine Whitten writes “LEAD
TECHNOLOGIES ANNOUNCES LINUX SUPPORT
Charlotte,
NC (December 8, 2000) – – LEAD Technologies, Inc., a LEADing
provider of imaging developer toolkits worldwide, announces the
release of LEADTOOLS Imaging for Linux, an imaging developer toolkit
for the Linux operating system. LEADTOOLS Imaging for Linux is built
directly upon Xlib, which offers developers more flexibility, greater
speed and ease in development, and independence of graphical interface.”
LEAD’s years of experience in imaging development have translated
to a Linux imaging toolkit that provides developers with better
imaging solutions. LEAD has specifically included unique viewing
and painting options in their paint bitmap functions for Linux,
solving painting (displaying the image) problems inherent to the
Linux operating system. Off-Screen image manipulation (on images
which reside in memory or files) is also supported. Developers can
choose to let the LEAD paint function map the image palette to the
Linux system palette avoiding unwanted color shifts in other applications.
Using the LEAD dithering and converting functions, developers can
paint any image with any bits/pixel in any screen depth, with no
change to the image.
The toolkit includes functionality
for performing image processing, from simple routines (rotate, flip
and invert, etc.) to more advanced (gamma correct, hue and saturation,
histogram equalize, emboss, etc.), in addition to document clean-up,
file format conversion (support for more than 40 formats), and more.
And, LEADTOOLS Imaging for Linux provides the ability to access
all of the included functionalities over a TCP/IP Network, through
the X Windows communication model. LEAD has tested the imaging toolkit
with various Linux distributions such as RedHat, Corel, SuSE, Linux
Mandrake, Caldera Linux and VA Linux, and has included installation
tips in the toolkit’s documentation.
Rich Little President of
LEAD states, “LEAD is excited to bring our powerful and market-leading
imaging technology to the Linux developer. We believe that Linux
programmers will greatly benefit from the more than 10 years of
experience LEAD has in the imaging toolkit business. LEADTOOLS is
the most comprehensive imaging toolkit on the market, so Linux programmers
will have a significant head start when integrating imaging into
their application.”
Some of the more than
40 LEADTOOLS for Linux supported file formats include:

• Tagged Image File Format support (including
  TIFF, TIFLZW, and CCITT) (TIF)
• MacPict file support (PCT)
• Adobe Photoshop 3.0 file support (PSD)
• Sun Raster file support (RAS)
• TARGA file support (TGA)
• ZSoft PCX file support (PCX)
• WinFax file support (WFX)
• Windows and OS/2 BMP file support
  (BMP)
• CALS raster file support (CAL)
• JPEG and LEAD CMP file support (CMP)
• Encapsulated PostScript file support
  (EPS)
• Raw FAX file support (FAX)
• GIF file support (GIF)
• IOCA file support (ICA)
• GEM Image file support (IMG)
• JBIG file support (JBG)

Image Processing options
include support for:

• High and Low Level Geometric Transformations
  (Resize, Trim, Flip, Reverse, Rotate, Rotate, etc.)
• Color Conversion (Color Separate,
  Color Merge, Convert from one Color Space to another)
• Color Expansion or Reduction (Dithering
  for custom palette, Grayscale, Halftone, etc.)
• Geometric Transformations (high level
  and low level)
• Modification of Intensity Values (Change
  Intensity, Gamma Correct, Change Contrast, etc.)
• Image Filtering (Add Noise, Despeckle,
  Emboss, Sharpen, Posterize, etc.)
• Histograms (Histo contrast, Histo
  Equalize, etc.)
• Image combine (Combine Underlay, Picturize)
• Interpretation of bitmap coordinates
  (Get/Set point, View perspective, etc.)
• Getting and setting pixel values (high
  level and low level)

-###-

About LEADTOOLS
LEADTOOLS is a family of comprehensive
toolkits designed to help programmers integrate raster, document,
medical, multimedia and vector imaging into their applications quickly
and easily. LEADTOOLS gives developers the most flexible and powerful
imaging technology available offering imaging technology for scanning,
color conversion, display/special effects, annotations, image processing,
compression, image format import/export filters, Internet imaging,
medical imaging, database imaging, printing, multimedia, Imaging
Common Dialogs, OCR, FlashPix format, screen capture and more. The
result of ten years of development, the toolkit literally puts millions
of lines of code at the fingertips of application developers.

About LEAD Technologies, Inc.
Founded in 1990, LEAD grew out of
years of research headed by Moe Daher to find a comprehensive compression
standard for digital images. LEAD is now the world-leading supplier
of imaging development toolkits, providing technology of the future,
today. LEAD brings to the market the most innovative and technically
superior products that provide the greatest possible value for its
customers. LEAD’s award winning imaging technology is chosen by
Microsoft, Hewlett Packard, Intel, Boeing, Xerox and thousands of
other companies for use in their high volume applications and internal
systems.

LEAD and LEADTOOLS are registered trademarks
of LEAD Technologies, Inc. All other product names are trademarks
of their respective owners.

“

The Dallas Morning News carries an AP report on the flurry of Napster user activity; a record number of MP3 files are being swapped in anticipation of a possible shutdown of the service. The 9th U.S. Circuit Court of Appeals is expected to rule on an injunction issued last year by a lower court.

In a guest editorial at LinuxDevices, Jerry Epplin takes a look at the RTLinux real time Linux modification patent. The main question: Is the patent enforceable? At this point, the answer is still one of uncertainty.

Opera 5 beta 6 is now available for i386 and PowerPC hardware in TGZ, RPM, and Debian package formats. This release fixes a previous CPU load issue and corrects a propblem with external mail client associations. For the uninitiated, Opera is a full-featured but very lightweight graphical Web browser. Links to download sites can be found in a post at LinuxToday.

From Unix Insider: “Why are there so many GUI toolkits? Who’s using all of those non-mainstream libraries? Last year,
Cameron Laird and Kathryn Soraiz profiled the leading GUI toolkits for general Unix development: Motif,
Tk, Qt, GTK+, and wxWindows. Now they round up the alternatives and summarize the state of their art.”

IBM has posted a transcript of the keynote speech delivered by company CEO Sam Palmisano at LinuxWorld Expo in New York.

jd142 writes “I went to http://www.dejanews.com/home_ps.shtml and found that they are now handled by Google. The complete press release can be found at the Google basic site. The Advanced Search looks very different from Deja’s advanced search page.”

ZDNET: “Of the myriad challenges Microsoft will face over the next few months, none will be as pressing as
persuading Windows and Office users to upgrade to the company’s XP versions.”

ZDNET: “Working in the press room of LinuxWorld
in New York this month, I found myself
checking e-mail on, of all things, a desktop
PC running Windows 98. Actually, there
were a couple of Linux stations in there.
But most of the desktops ran Windows,
and the Linux machines were always occupied. And I was
so looking forward to Red Hat.”