The Linux Letter for
December 27, 1999
After a three week hiatus,
it's time to get back to work! The last time we met, I told you
all about the projects that were on the front burner here at the
computer ranch. Almost everything is well underway. So now we
can look ahead to what's coming for Linux next year!
Linux 2.4 is just around the
corner, coming very soon into 2000. If you remember the
ballyhooed introduction of Linux 2.2, you know that there were
some huge improvements over the old 2.0 kernel. Don't expect the
same sort of advances from 2.2 to 2.4. According to Joe
Pranevich's Wonderful World of Linux 2.4, new kernels will come
at a greater clip than before and that means fewer significant
improvements, but more rapid incremental changes.
Most of the changes won't be
visible to the average user. High end systems that run many
processes will benefit by an increase in the number of
simultaneous threads...from 1024 to a potential of 16,000. Intel
systems will be able to support up to 4GB of physical memory.
Linux 2.2 supported the Intel
memory type range registers (MTRR) and the support will be
improved in 2.4. AMD K7 processors have two of them and Cyrix
processors implement a variation called MCR. Linux 2.4 will
support them. If your system has multiple processors, you know
that Linux 2.2 improved the support for the advanced
programmable interrupt controller (IO-APIC) that spreads
interrupts across processors. Kernel 2.4 takes this a step
further and supports high-end system that have multiple IO-APICs,
which means that Linux will scale even better on systems with
If you're like me, you
probably have a system with the Universal Serial Bus. USB
support will be available in Linux 2.4. While individual device
support is slowly growing, many hardworking programmers are
readying drivers for popular devices right now. PnP for ISA
devices will be included in the kernel, so no external utilities
or drivers will be necessary. Just don't count on installing
that Winmodem anytime soon.
IDE device support will also
improve. The total number of IDE controllers allowed will be 10
in Linux 2.4, up from a maximum of 4 in 2.2. That allows for a
potential of 20 IDE devices in a single system. UDMA support
will be a new feature.
The same array of file systems
in Linux 2.2 will be present in 2.4. OS/2 users will be able to
write as well as read from their partitions. Also, those of us
who mount Windows drives using SMB won't have to enable the
workaround for the broken Windows 9x systems. The kernel will be
able to detect the system and implement the fixes on the fly. An
even more anticipated improvement is the upgrade of the network
file system (NFS) to be NFS3 compatible.
USB keyboards and mice will
work! They behave just like their standard serial or PS/2
counterparts that we're used to.
Parallel port performance has
been improved to allow for Plug and Play devices and DMA
support. Printers and other parallel devices that support them
will show a noticeable speed increase.
The networking layer has been
completely rewritten to scale much better than before. It has
been optimized to allow it to work with odd networking stacks
(including Windows). Linux 2.4 will be the first operating
system to be fully compatible with Ipv4.
PPP has been rewritten to
modularize the code which combines the PPP layers from ISDN with
those of serial devices.
If you can't wait for Linux
2.4 to be released, you can sample much of it by downloading and
installing the latest development kernel (2.3.33 as of this
writing). The usual warnings about running developmental beta
Wonderful World of Linux 2.4: http://linuxtoday.com/stories/10698.html
Linux Kernels: http://www.kernel.org
So you're done using your CD-ROM drive and
you've tried to unmount it, but mount tells you that it's busy.
Don't give up...find out what process is using it! Just issue
fuser -l /dev/cdrom
The command will list the processes using
the CD-ROM's file system. Or, if you're feeling adventurous and
don't care what processes are using the CD-ROM, try:
fuser -k /dev/cdrom
This will kill all of the processes that
are using the CD-ROM.